开云体育

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

#121 Issued Wednesday May 2, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 69.9 68.4 68.0

There had been 1 day with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 0.

There had been 4 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 71 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 0 0 1 0 0 0 1 1.

The 24 hour period maximum and minimum solar wind speed ranged between 428 & 352 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 02, 2018- steady.

HF radio wave propagation condition “trend” May 03, 2018- steady.

HF radio wave propagation condition “trend” May 04, 2018- steady.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are firmly in the fall/spring equinox type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most evenly balanced across the equator during the fall and spring equinox.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

Southern Hemisphere Radio Wave Propagation Forecast g-

We are firmly in the fall/spring equinox type of HF radio wave propagation
conditions. Globally HF radio wave propagation conditions are most evenly
balanced across the equator during the fall and spring equinox.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.
This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.


Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast


but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

#122 Issued Thursday May 3, 2018 at 1415 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 67.5 67.1 67.1

There had been 2 days with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 0.

There had been 5 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 72 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 1 2 1 1 1 1 0 0.

The 24 hour period maximum and minimum solar wind speed ranged between 390 & 339 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 03, 2018- steady.

HF radio wave propagation condition “trend” May 04, 2018- steady.

HF radio wave propagation condition “trend” May 05, 2018- deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are firmly in the fall/spring equinox type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most evenly balanced across the equator during the fall and spring equinox.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

Southern Hemisphere Radio Wave Propagation Forecast g-

We are firmly in the fall/spring equinox type of HF radio wave propagation
conditions. Globally HF radio wave propagation conditions are most evenly
balanced across the equator during the fall and spring equinox.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.


Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast

but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

#123 Issued Friday May 4, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 67.3 66.5 66.9

<<<The 66.5 reading is the lowest so far in the solar cycle 24 down slide towards solar minimum. At solar minimum the daily solar flux number stays in the low to mid 60’s range for years at a time.

Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type solar minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring but isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified.

I also forecasted that solar cycle 25 would be almost non nonexistent. >>>

There had been 3 days with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 0.

There had been 6 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 73 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 1 0 0 0 1 1 1 2.

The 24 hour period maximum and minimum solar wind speed ranged between 352 & 325 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 04, 2018- steady.

HF radio wave propagation condition “trend” May 05, 2018- steady then deteriorating.

HF radio wave propagation condition “trend” May 06, 2018- deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 29700 frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-29700 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).


3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 29700 frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.


Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

On Thursday May 3, 2018 the daily solar flux index numbers (DSFI) were 67.3 66.5 66.9

The 66.5 reading is the lowest so far in the solar cycle 24 down slide
towards solar minimum. At solar minimum the daily solar flux number stays in
the low to mid 60’s range for years at a time.

Solar minimum may begin later this year and may last longer than any
previous solar cycle in the 20th century. When solar cycle 25 finally gets
going it could be the weakest since the middle of the 19th century. Another
Dalton type solar minimum may occur with a corresponding cooling of earth’s
climate. This would negate anthropogenic climate change if it were occurring
but isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest
solar cycle in the past 100 years. That forecast verified.

I also forecasted that solar cycle 25 would be almost non nonexistent.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this solar cycle 25
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this solar cycle 25 forecast that I have produced from the RAW
public domain data is my personal intellectual property. Therefore this
solar cycle 25 forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this solar cycle 25 forecast,
as long as you redistribute it in its entirety and
give me credit for it.

Solar cycle forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

73 & GUD DX,
Thomas F. Giella, W4HM
Lakeland, FL, USA

/g/w4hmradiowavepropagationforecast

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast

but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

#124 Issued Saturday May 5, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type solar grand minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))

The daily solar flux index numbers (DSFI) were 69.0 67.8 68.8

There had been 5 days with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 13.

There had been 1 day with a daily sunspot number (DSSN) greater than 0.

Newly emerged sunspot group #12708 was located near S09E52 with a relatively simple beta magnetic signature capable of releasing a very small B class solar flare and an isolated small in size C class solar flare.

In 2018 there had been 73 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 0 1 1 1 1 1 1 1.

The 24 hour period maximum and minimum solar wind speed ranged between 348 & 344 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 5, 2018- steady then deteriorating.

HF radio wave propagation condition “trend” May 6, 2018- deteriorating.

HF radio wave propagation condition “trend” May 7, 2018- deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 29700 frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-29700 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).


3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 29700 frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast


but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

#125 Issued Sunday May 6, 2018 at 1515 UTC

Important Solar, Space & Geomagnetic Weather Indices-

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type solar grand minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))

The daily solar flux index numbers (DSFI) were 68.3 67.6 68.1

There had been 6 days with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 14.

There had been 2 days in a row with a daily sunspot number (DSSN) greater than 0.

Newly emerged sunspot group #12708 was located near S09E39 with a relatively simple beta magnetic signature capable of releasing a very small B class solar flare and an isolated small in size C class solar flare.

In 2018 there had been 73 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a moderate geomagnetic storming level to quiet geomagnetic condition of 1 1 0 3 4 5 4 6.

The 24 hour period maximum and minimum solar wind speed ranged between 554 & 304 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 6, 2018- deteriorating.

HF radio wave propagation condition “trend” May 7, 2018- deteriorating.

HF radio wave propagation condition “trend” May 8, 2018- deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 29700 frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-29700 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).


3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 29700 frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.


Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast

but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

#126 Issued Monday May 7, 2018 at 1500 UTC

Important Solar, Space & Geomagnetic Weather Indices-

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type grand solar grand minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))

The daily solar flux index numbers (DSFI) were 68.1 67.2 69.0

There had been 7 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 14.

There had been 3 days in a row with a daily sunspot number (DSSN) greater than 0.

Sunspot group #12708 was located near S10E17 with a relatively simple beta magnetic signature capable of releasing a very small B class solar flare and an isolated small in size C class solar flare.

In 2018 there had been 73 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a moderate geomagnetic storming level to unsettled geomagnetic condition of 6 4 3 3 3 3 4 5.

The 24 hour period maximum and minimum solar wind speed ranged between 717 & 606 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 7, 2018- deteriorating.

HF radio wave propagation condition “trend” May 8, 2018- steady.

HF radio wave propagation condition “trend” May 9, 2018- steady.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).


3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.


Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

#127 Issued Monday May 8, 2018 at 1500 UTC

Important Solar, Space & Geomagnetic Weather Indices-

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type grand solar grand minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))

The daily solar flux index numbers (DSFI) were 68.5 69.6 68.5

There had been 8 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 14.

There had been 4 days in a row with a daily sunspot number (DSSN) greater than 0.

Sunspot group #12708 was located near S09E12 with a relatively simple beta magnetic signature capable of releasing a very small B class solar flare and an isolated small in size C class solar flare.

In 2018 there had been 73 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at an active to quiet geomagnetic condition of 4 4 3 2 3 3 2 3.

The 24 hour period maximum and minimum solar wind speed ranged between 697 & 569 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 8, 2018- steady.

HF radio wave propagation condition “trend” May 9, 2018- improving.

HF radio wave propagation condition “trend” May 10, 2018- improving.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).


3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

#128 Issued Wednesday May 9, 2018 at 1530 UTC

Important Solar, Space & Geomagnetic Weather Indices-

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type grand solar grand minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))

The daily solar flux index numbers (DSFI) were 70.2 69.6 70.1

There had been 8 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

The DSFI streak below 70 may come to an end today Wednesday May 9, 2018.

The official daily sunspot number (DSSN) was 25.

There had been 5 days in a row with a daily sunspot number (DSSN) greater than 0.

Sunspot group #12708 was located near S09E01 with a relatively simple beta magnetic signature capable of releasing a very small B class solar flare and an isolated small in size C class solar flare.

Newly emerged/risen sunspot group #12709 was located near N05E65 with a simple alpha magnetic signature capable of releasing a very, very small A class solar flare and an isolated very small in size B class solar flare.

In 2018 there had been 73 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at an active to quiet geomagnetic condition of 2 3 2 3 2 3 4 2.

The 24 hour period maximum and minimum solar wind speed ranged between 717 & 537 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 9, 2018- steady.

HF radio wave propagation condition “trend” May 10, 2018- improving.

HF radio wave propagation condition “trend” May 11, 2018- improving.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type grand solar grand minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))

#129 Issued Thursday May 10, 2018 at 1530 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 70.0 69.6 69.9

There had been 9 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

The DSFI streak below 70 may come to an end today Thursday May 10, 2018.

The official daily sunspot number (DSSN) was 22.

There had been 6 days in a row with a daily sunspot number (DSSN) greater than 0.

Sunspot group #12708 was located near S09W11 with a simple alpha magnetic signature capable of releasing a very, very small in size A class solar flare and an isolated very small in size B class solar flare.

Sunspot group #12709 was located near N05E52 with a simple alpha magnetic signature capable of releasing a very, very small in size A class solar flare and an isolated very small in size B class solar flare.

In 2018 there had been 73 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at an active to quiet geomagnetic condition of 3 2 2 2 2 2 4 4.

The 24 hour period maximum and minimum solar wind speed ranged between 699 & 553 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 10, 2018- steady.

HF radio wave propagation condition “trend” May 11, 2018- improving.

HF radio wave propagation condition “trend” May 12, 2018- improving.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).


3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast


but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type grand solar grand minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))

#130 Issued Friday May 11, 2018 at 1200 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 69.9 69.6 74.4

There had been 10 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 11.

There had been 7 days in a row with a daily sunspot number (DSSN) greater than 0.

Sunspot group #12708 was located near S10W13 with a simple alpha magnetic signature capable of releasing a very, very small in size A class solar flare and an isolated very small in size B class solar flare.

Sunspot group #12709 was located near N05E52 with a simple alpha magnetic signature capable of releasing a very, very small in size A class solar flare and an isolated very small in size B class solar flare.

In 2018 there had been 73 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at an unsettled to quiet geomagnetic condition of 3 3 3 3 2 3 1 2.

The 24 hour period maximum and minimum solar wind speed ranged between 583 &451 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 11, 2018- improving.

HF radio wave propagation condition “trend” May 12, 2018- improving.

HF radio wave propagation condition “trend” May 13, 2018- improving.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type grand solar grand minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))

#131 Issued Saturday May 12, 2018 at 1615 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 70.5 70.3 70.4

There had been 10 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

We had 1 day with a 2000 UTC daily solar flux index number (DSFI) above 70.

The official daily sunspot number (DSSN) was 11.

There had been 8 days in a row with a daily sunspot number (DSSN) greater than 0.

Sunspot group #12708 had weakened into a spotless plage.

Sunspot group #12709 was located near N05E25 with a simple alpha magnetic signature capable of releasing a very, very small in size A class solar flare and an isolated very small in size B class solar flare.

In 2018 there had been 73 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at an unsettled to quiet geomagnetic condition of 2 3 3 2 2 2 3 3.

The 24 hour period maximum and minimum solar wind speed ranged between 503 & 427 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 12, 2018- improving.

HF radio wave propagation condition “trend” May 13, 2018- improving.

HF radio wave propagation condition “trend” May 14, 2018- improving.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and 4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
MF/HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type grand solar grand minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))

#132 Issued Sunday May 13, 2018 at 1530 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 69.8 69.8 69.4

There had been 1 day with a 2000 UTC daily solar flux index number (DSFI) below 70.

We had 1 day with a 2000 UTC daily solar flux index number (DSFI) above 70.

The official daily sunspot number (DSSN) was 12.

There had been 9 days in a row with a daily sunspot number (DSSN) greater than 0.

Sunspot group #12709 was located near N05E11 with a simple alpha magnetic signature capable of releasing a very, very small in size A class solar flare and an isolated very small in size B class solar flare.

In 2018 there had been 73 days with a daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at an unsettled to quiet geomagnetic condition of 3 3 1 1 1 1 2 2.

The 24 hour period maximum and minimum solar wind speed ranged between 508 & 424 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 13, 2018- improving.

HF radio wave propagation condition “trend” May 14, 2018- improving.

HF radio wave propagation condition “trend” May 15, 2018- steady.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).


3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S0 at night and S3-4 at day,

21000-21850 kHz- S0 at night and S1-2 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1 at day,

28000-29700 kHz- S0 at night and S0 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast


but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets going it could be the weakest since the middle of the 19th century. Another Dalton type grand solar grand minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))


#133 Issued Monday May 14, 2018 at 1545 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 70.5 70.9 70.1

There had been 1 day with a 2000 UTC daily solar flux index number (DSFI) above 70.

The official daily sunspot number (DSSN) was 11.

There had been 10 days in a row with a daily sunspot number (DSSN) greater than 0.

(((But today Monday May 14, 2018 the unofficial sunspot number (DSSN) has fallen back to 0 once again.)))

In 2018 there had been 73 days with an official daily sunspot number (DSSN) of 0.

Sunspot group #12709 was located near N04W02 with a simple alpha magnetic signature capable of releasing a very, very small in size A class solar flare and an isolated very small in size B class solar flare.

(((But on Monday May 14, 2018 sunspot group #12709 has weakened into a spotless plage.)))

The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 2 2 2 2 2 2 2 2.

The 24 hour period maximum and minimum solar wind speed ranged between 456 & 389 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 14, 2018- improving.

HF radio wave propagation condition “trend” May 15, 2018- improving.

HF radio wave propagation condition “trend” May 16, 2018- steady.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).


3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast


but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

(((((Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets underway it could be the weakest since the middle of the 19th century. Another Dalton type lesser grand solar minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.)))))

#134 Issued Tuesday May 15, 2018 at 1415 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 69.9 70.3 70.1

There had been 2 days in a row with a 2000 UTC daily solar flux index number (DSFI) above 70.

The official daily sunspot number (DSSN) was 0.

There had been 1 day with a daily sunspot number (DSSN) of 0.

In 2018 there had been 74 days with an official daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 1 1 1 1 1 1 1 2.

The 24 hour period maximum and minimum solar wind speed ranged between 421 & 346 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 15, 2018- steady.

HF radio wave propagation condition “trend” May 16, 2018- steady.

HF radio wave propagation condition “trend” May 17, 2018- deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).


3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+10 at night and S4-7 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+5 at night and S5-8 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S9+1 at day,

21000-21850 kHz- S0 at night and S5-8 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S1 at day.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast


but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

W4HM Solar Cycle 25 Forecast-

Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets underway it could be the weakest since the middle of the 19th century. Another Dalton type lesser grand solar minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.


#135 Issued Wednesday May 16, 2018 at 1515 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 70.6 70.3 69.7

There had been 3 days in a row with a 2000 UTC daily solar flux index number (DSFI) above 70.

The official daily sunspot number (DSSN) was 0.

There had been 2 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 74 days with an official daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 1 1 1 1 1 1 1 2.

The 24 hour period maximum and minimum solar wind speed ranged between 380 & 307 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 16, 2018- steady.

HF radio wave propagation condition “trend” May 17, 2018- deteriorating.

HF radio wave propagation condition “trend” May 18, 2018- deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).

Southern Hemisphere Radio Wave Propagation Forecast g-

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+10 at night and S4-7 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+5 at night and S5-8 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S9+1 at day,

21000-21850 kHz- S0 at night and S5-8 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S1 at day.

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast


but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

W4HM Solar Cycle 25 Forecast- Short and to the point.

Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets underway it could be the weakest since the middle of the 19th century. Another Dalton type lesser grand solar minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.


#136 Issued Thursday May 17, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 69.8 69.9 68.8

There had been 1 day with a 2000 UTC daily solar flux index number (DSFI) of lower than 70.

The official daily sunspot number (DSSN) was 0.

There had been 3 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 76 days with an official daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 0 0 0 0 1 1 1 1.

The 24 hour period planetary A index (Ap) index maximum and minimum ranged between 5 & 2, which had been at a quiet geomagnetic level.

The 24 hour period maximum and minimum solar wind speed ranged between 330 & 274 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 17, 2018- deteriorating.

HF radio wave propagation condition “trend” May 18, 2018- steady.

HF radio wave propagation condition “trend” May 19, 2018- improving.

Northern Hemisphere Radio Wave Propagation Forecast g-

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).

Southern Hemisphere Radio Wave Propagation Forecast g-

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+10 at night and S4-7 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+5 at night and S5-8 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S9+1 at day,

21000-21850 kHz- S0 at night and S5-8 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S1 at day.

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast


but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

W4HM Solar Cycle 25 Forecast- Short and to the point.

Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets underway it could be the weakest since the middle of the 19th century. Another Dalton type lesser grand solar minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.


#137 Issued Friday May 18, 2018 at 1530 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 69.2 69.0 71.0

There had been 2 days with a 2000 UTC daily solar flux index number (DSFI) of lower than 70.

The official daily sunspot number (DSSN) was 0.

There had been 4 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 77 days with an official daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at an unsettled to quiet geomagnetic condition of 3 2 2 3 3 2 2 2.

The 24 hour period maximum and minimum solar wind speed ranged between 467 & 400 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 18, 2018- deteriorating.

HF radio wave propagation condition “trend” May 19, 2018- steady.

HF radio wave propagation condition “trend” May 20, 2018- improving.

Northern Hemisphere Radio Wave Propagation Forecast g-

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).

Southern Hemisphere Radio Wave Propagation Forecast g-

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+10 at night and S4-7 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+5 at night and S5-8 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S9+1 at day,

21000-21850 kHz- S0 at night and S5-8 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S1 at day.

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist and
one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast


but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

W4HM Solar Cycle 25 Forecast- Short and to the point.

Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets underway it could be the weakest since the middle of the 19th century. Another Dalton type lesser grand solar minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.


#138 Issued Saturday May 19, 2018 at 1445 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.9 69.4 68.7

There had been 3 days with a 2000 UTC daily solar flux index number (DSFI) of lower than 70.

The official daily sunspot number (DSSN) was 0.

There had been 5 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 78 days with an official daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 1 1 0 1 1 1 1 1.

The 24 hour period maximum and minimum solar wind speed ranged between 430 & 350 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 19, 2018- steady.

HF radio wave propagation condition “trend” May 20, 2018- steady.

HF radio wave propagation condition “trend” May 21, 2018- steady.

Northern Hemisphere Radio Wave Propagation Forecast g-

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).

Southern Hemisphere Radio Wave Propagation Forecast g-

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+10 at night and S4-7 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+5 at night and S5-8 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S9+1 at day,

21000-21850 kHz- S0 at night and S5-8 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S1 at day.

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.

Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.

Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.

It’s the only daily global HF radio wave propagation forecast produced on
the planet.

I'm a retired heliophysicist, terrestrial meteorologist/climatologist, physical
oceanographer and one of the few on the planet with advanced education and forecast
experience in both disciplines. In terrestrial weather forecasting I
have 45 years of experience and in solar, space and geomagnetic weather
forecasting 34 years.

Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ?
1988-2018.

If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at

thomasfgiella@...

I enjoy hearing from likeminded fellow radio enthusiasts.

Hams and SWLs that are interested in solar, space & geomagnetic weather as
well as radio wave propagation are a special group of people interested in
broadening their knowledge in science.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Supporting images associated with this daily HF radio wave propagation forecast can be found in my Facebook account at



and in my Twitter account at



Last but not least here is my new HF radio wave propagation web page where you can sign up to receive this daily HF radio wave propagation forecast via email. /g/w4hmradiowavepropagationforecast but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by Groups.io, so
you have to sign up by using an existing email address and creating a
password.

W4HM Solar Cycle 25 Forecast- Short and to the point.

Solar minimum may begin later this year and may last longer than any previous solar cycle in the 20th century. When solar cycle 25 finally gets underway it could be the weakest since the middle of the 19th century. Another Dalton type lesser grand solar minimum may occur with a corresponding cooling of earth’s climate. This would negate anthropogenic climate change if it were occurring which it isn’t.

On February 1, 2008 I forecasted that solar cycle 24 would be the smallest solar cycle in the past 100 years. That forecast verified. I also forecasted that solar cycle 25 would be almost non nonexistent.


#139 Issued Sunday May 20, 2018 at 1630 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 70.3 70.3 70.0

There had been 1 day with a 2000 UTC daily solar flux index number (DSFI) of 70
or higher.

Prior to that there had been 3 days with a 2000 UTC daily solar flux index number (DSFI) of lower than 70.

The official daily sunspot number (DSSN) was 0.

There had been 6 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 79 days with an official daily sunspot number (DSSN) of 0.

The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 0 0 0 0 1 1 1 1.

The 24 hour period maximum and minimum solar wind speed ranged between 356 & 327 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition “trend” May 20, 2018- steady.

HF radio wave propagation condition “trend” May 21, 2018- steady.

HF radio wave propagation condition “trend” May 22, 2018- deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9 +1 to 9 at night and S1-3 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and S4-7 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S8-9 at day,

21000-21850 kHz- S0 at night and S4-7 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S0-1 at day.

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.

Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges will open via short north-south and east-west propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds form and line up favorably much longer propagation paths open up on east-west paths. And last but not least north-south propagation paths occur across the equator via trans equatorial propagation (TEP).

Southern Hemisphere Radio Wave Propagation Forecast g-

3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- S9+10 at night and S4-7 at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- S9+5 at night and S5-8 at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at night and S9+1 at day,

21000-21850 kHz- S0 at night and S5-8 at day,

24890-24990, 25600-26100 kHz- S0 at night and S1-3 at day,

28000-29700 kHz- S0 at night and S1 at day.

We are now moving into the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.

During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.

This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public. It does outperform VOA CAP.

And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP software, I do check the actual band conditions at my location in
the USA and tweak the forecast manually where and when necessary.

I also check global HF radio wave propagation conditions via remoted radio
receivers on every continent of the globe and tweak the forecast manually if
and when necessary.

And last but not least I look at ionsonde stations on every continent of the
globe.

The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ? wave dipole up at 40 feet.

The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ? wave dipole up at 40 feet.

The hamateur radio CW mode RF signal levels received are based on 50 watts
and ? wave dipole up at 40 feet.

The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ? wave dipole up at 40 feet.

The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.

Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.

Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.

Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2). Also by propagation path.

The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.

Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.

Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.

Lower high frequency (80-30 meters) propagation conditions are impacted in a
negative manner not so much by variations in the maximum usable frequency
(MUF) along a particular propagation path and time but rather due to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5 &
greater) that increase signal absorption via the E layer (the altitude of
the radio aurora). Also increases in the lowest usable frequency (LUF) via D
layer RF signal absorption due to hard x-rays, galactic cosmic waves,
elevated background solar flux levels greater than B0 and energetic proton
flux levels at energies greater than 10 MeV (10+0).

Higher frequency (20-10 meters) propagation conditions are impacted in a
negative manner by variations in the maximum usable frequency (MUF) along a
particular propagation path and time due to the current sunspot number and
also due to elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also D layer RF signal absorption due to elevated (greater than B0)
background solar flux levels. Also to a lesser extent elevated proton flux
at energies greater than 10 MeV (10+0).

GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-

NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted ? 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.

All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.

1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.

2.) A daily sunspot number of 150 or higher, 200 or higher best.

3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.

5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.

6.) Energetic protons no greater than 10 MeV (10+0).

7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.

8.) No current STRATWARM alert.

9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.

10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.

Standard Disclaimer-

Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).

However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ?
1988-2018 by Thomas F. Giella, W4HM.

Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.

Also HF radio wave propagation forecasting is still an inexact
science and therefore also an art. The forecasts are not official but for
educational and hobby related purposes only and are subject to human error
and acts of God, therefore no guarantee or warranty implied.