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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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at



but without supporting images.

It's a NO SPAM voluntary "opt" in email type group hosted by contesting on line (COL), so you have to sign up by using an existing email address and creating a password.

And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at




#80 Issued Wednesday March 21, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 69.0 68.8 69.3

There had been 1 day in a row with a 2000 UTC daily solar flux index number (DSFI) below 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 43 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 to unsettled geomagnetic condition of 2 3 0 0 1 1 2 1.

The 24 hour period maximum and minimum solar wind speed ranged between 463 & 347 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 21, 2018- steady state

HF radio wave propagation condition trend March 22, 2018- deteriorating

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary. And last but not least I check data from ionsonde's scattered around the planet.

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).

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 storms (Kp-5 & >) 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 geomagnetic storms of Kp-5 & >. Also D layer RF signal absorption due to elevated (>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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at

/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.

And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at




#81 Issued Thursday March 22, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.7 69.3 68.3

There had been 2 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 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 44 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 0 0 0 0 2 1.

The 24 hour period maximum and minimum solar wind speed ranged between 382 & 306 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 22, 2018- deteriorating

HF radio wave propagation condition trend March 23, 2018- deteriorating

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary. And last but not least I check data from ionsonde's scattered around the planet.

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).

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 storms (Kp-5 & >) 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 geomagnetic storms of Kp-5 & >. Also D layer RF signal absorption due to elevated (>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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at

/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.

And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at

.


#82 Issued Friday March 23, 2018 at 1315 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.1 68.5 67.9

There had been 3 days in a row 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 45 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 to unsettled geomagnetic condition of
1 2 1 1 1 2 3 3.

The 24 hour period maximum and minimum solar wind speed ranged between
467 & 320 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 23, 2018- deteriorating

HF radio wave propagation condition trend March 24, 2018- deteriorating

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary. And last but not least I check data from ionsonde's scattered around the planet.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page

/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.

And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at

.


#83 Issued Saturday March 24, 2018 at 1330 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.7 68.1 67.9

There had been 4 days in a row 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 46 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 to active geomagnetic condition of
4 3 1 2 2 1 3 4.

The 24 hour period maximum and minimum solar wind speed ranged between
531 & 372 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 24, 2018- deteriorating

HF radio wave propagation condition trend March 25, 2018- deteriorating

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary. And last but not least I check data from ionsonde's scattered around the planet.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page

/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.

And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at

.


#84 Issued Sunday March 25, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 67.1 67.6 68.3

There had been 5 days in a row 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 47 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 to unsettled geomagnetic condition of 2 2 1 2 2 2 2 3.

The 24 hour period maximum and minimum solar wind speed ranged between 533 & 381 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 25, 2018- deteriorating

HF radio wave propagation condition trend March 26, 2018- deteriorating

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary. And last but not least I check data from ionsonde's scattered around the planet.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page

/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.

And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at

.


#85 Issued Monday March 26, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.3 68.3 68.6

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

The official daily sunspot number (DSSN) was 0.

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

In 2018 there had been 48 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 to active geomagnetic condition of 3 4 3 3 2 2 2 4.

The 24 hour period maximum and minimum solar wind speed ranged between 479 & 435 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 26, 2018- steady state

HF radio wave propagation condition trend March 27, 2018- steady state

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now entering 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary. And last but not least I check data from ionsonde's scattered around the planet.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page

/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.


And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at




#86 Issued Tuesday March 27, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.0 67.8 67.6

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 0.

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

In 2018 there had been 49 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 to unsettled geomagnetic condition of 3 3 3 2 2 2 2 3.

The 24 hour period maximum and minimum solar wind speed ranged between 556 & 446 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 27, 2018- improving

HF radio wave propagation condition trend March 28, 2018- steady state

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page

/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.


And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at




#87 Issued Wednesday March 28, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 67.5 68.3 67.7

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

The official daily sunspot number (DSSN) was 0.

There had been 9 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 50 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 to unsettled geomagnetic condition of 3 3 2 2 2 1 0 1.

The 24 hour period maximum and minimum solar wind speed ranged between 556 & 418 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 28, 2018- improving

HF radio wave propagation condition trend March 29, 2018- steady state

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page at

/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.


And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at




#88 Issued Thursday March 29, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.7 68.6 68.5

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

The official daily sunspot number (DSSN) was 0.

There had been 10 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 51 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 1 1 0 0 0 0 0.

The 24 hour period maximum and minimum solar wind speed ranged between 445 & 345 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 29, 2018- steady state

HF radio wave propagation condition trend March 30, 2018- deteriorating

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page at

/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.


And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at




#89 Issued Thursday March 30, 2018 at 1400 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.5 69.0 68.6

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 0.

But this Friday March 30, 2018 a newly numbered sunspot group is rising around the east limb of the sun located near S09E68 with a simple alpha magnetic signature. It remains to be seen how long it lasts.

There had been 11 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 52 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 2 1 1 1 1.

The 24 hour period maximum and minimum solar wind speed ranged between 450 & 342 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 30, 2018- steady state

HF radio wave propagation condition trend March 31, 2018- deteriorating

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page at

/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.


And last but not least I also post solar, space and geomagnetic weather goings on and some images in my Twitter account at




#90 Issued Saturday March 31, 2018 at 1400 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.4 68.8 68.7

There had been 11 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 11.

On Friday March 30, 2018 a newly risen sunspot group #12703 was located near S09E61 with a simple alpha magnetic signature capable of producing very small B class solar flares.

It remains to be seen how long it lasts.

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

In 2018 there had been 52 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 2 1 1 1 1.

The 24 hour period maximum and minimum solar wind speed ranged between 464 & 356 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend March 31, 2018- steady state

HF radio wave propagation condition trend April 1, 2018- steady state

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page of

/g/w4hmradiowavepropagationforecast

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.


#93 Issued Tuesday April 3, 2018 at 1500 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.3 68.4 68.0

There had been 14 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 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 54 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 2 1 0 1 1 1 1 1.

The 24 hour period maximum and minimum solar wind speed ranged between 449 & 369 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend April 3, 2018- steady state

HF radio wave propagation condition trend April 4, 2018- steady state

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page of

/g/w4hmradiowavepropagationforecast

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.


#94 Issued Wednesday April 4, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.0 67.8 67.4

There had been 15 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 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 55 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 0 0 0 0 0.
The 24 hour period maximum and minimum solar wind speed ranged between
416 & 334 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend April 4, 2018- steady state

HF radio wave propagation condition trend April 5, 2018- steady state

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page of

/g/w4hmradiowavepropagationforecast

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.


#95 Issued Thursday April 5, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 67.2 68.5

There had been 16 days in a row 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 56 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 2 2 2 1 2.

The 24 hour period maximum and minimum solar wind speed ranged between 387 & 319 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend April 5, 2018- steady state

HF radio wave propagation condition trend April 6, 2018- steady state

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

?

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 other 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 at my new web page of

?

/g/w4hmradiowavepropagationforecast

?

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.

?

?

#96 Issued Friday April 6, 2018 at 1400 UTC

?

Important Solar, Space & Geomagnetic Weather Indices-

?

The daily solar flux index numbers (DSFI) were 66.7 66.4 66.8

?

The 2000 UTC daily solar flux number (DSFI) of 66.4 was the lowest so far in waning solar cycle 24.

?

There had been 17 days in a row 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 57 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 to unsettled geomagnetic condition of

3 2 1 0 1 2 3 2.

The 24 hour period maximum and minimum solar wind speed ranged between

445 & 343 km/s.

?

Global Daily HF Radio Wave Propagation Forecast-

?

HF radio wave propagation condition trend April 6, 2018- steady state

?

HF radio wave propagation condition trend April 7, 2018- steady state

?

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

?

Northern Hemisphere Radio Wave Propagation Forecast g-

?

We are now 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- very good at night and poor to fair at day,

?

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

?

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

?

21000-21850 kHz- very poor at night and fair to good at day,

?

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

?

28000-29700 kHz- very poor at night and poor at day.

?

Excellent- S9+10 or >

Very Good- S9 +1-9

Good- S8-9

Fair- S4-7

Poor- S1-3

Very Poor- S0

?

Southern Hemisphere Radio Wave Propagation Forecast g-

?

We are now 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- very good at night and poor to fair at day,

?

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

?

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

?

21000-21850 kHz- very poor at night and fair to good at day,

?

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

?

28000-29700 kHz- very poor at night and poor at day.

?

Excellent- S9+10 or >

Very Good- S9 +1-9

Good- S8-9

Fair- S4-7

Poor- S1-3

Very Poor- S0

?

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.

?

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

?

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).

?

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

?

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 other 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 at my new web page of

?

/g/w4hmradiowavepropagationforecast

?

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.

?

?

#97 Issued Saturday April 7, 2018 at 1400 UTC

?

Important Solar, Space & Geomagnetic Weather Indices-

?

The daily solar flux index numbers (DSFI) were 66.4 67.3 67.7

There had been 18 days in a row 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 58 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 1 0 1 1 1.

The 24 hour period maximum and minimum solar wind speed ranged between?451 & 345 km/s.

?

Global Daily HF Radio Wave Propagation Forecast-

?

HF radio wave propagation condition trend April 7, 2018- steady state

?

HF radio wave propagation condition trend April 8, 2018- steady state

?

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

?

Northern Hemisphere Radio Wave Propagation Forecast g-

?

We are now 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- very good at night and poor to fair at day,

?

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

?

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

?

21000-21850 kHz- very poor at night and fair to good at day,

?

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

?

28000-29700 kHz- very poor at night and poor at day.

?

Excellent- S9+10 or >

Very Good- S9 +1-9

Good- S8-9

Fair- S4-7

Poor- S1-3

Very Poor- S0

?

Southern Hemisphere Radio Wave Propagation Forecast g-

?

We are now 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- very good at night and poor to fair at day,

?

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

?

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

?

21000-21850 kHz- very poor at night and fair to good at day,

?

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

?

28000-29700 kHz- very poor at night and poor at day.

?

Excellent- S9+10 or >

Very Good- S9 +1-9

Good- S8-9

Fair- S4-7

Poor- S1-3

Very Poor- S0

?

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.

?

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

?

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).

?

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

?

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 other 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 at my new web page of

?

/g/w4hmradiowavepropagationforecast

?

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.

?

?

#98 Issued Sunday April 8, 2018 at 1700 UTC

?

Important Solar, Space & Geomagnetic Weather Indices-

?

The daily solar flux index numbers (DSFI) were 67.1 66.8 67.4

There had been 19 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

?

The official daily sunspot number (DSSN) was 0.

?

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

?

In 2018 there had been 59 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 1 1 1 1 1 0 2.

The 24 hour period maximum and minimum solar wind speed ranged between?380 & 342 km/s.

?

Global Daily HF Radio Wave Propagation Forecast-

?

HF radio wave propagation condition trend April 8, 2018- steady state

?

HF radio wave propagation condition trend April 9, 2018- steady state

?

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

?

Northern Hemisphere Radio Wave Propagation Forecast g-

?

We are now 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- very good at night and poor to fair at day,

?

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

?

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

?

21000-21850 kHz- very poor at night and fair to good at day,

?

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

?

28000-29700 kHz- very poor at night and poor at day.

?

Excellent- S9+10 or >

Very Good- S9 +1-9

Good- S8-9

Fair- S4-7

Poor- S1-3

Very Poor- S0

?

Southern Hemisphere Radio Wave Propagation Forecast g-

?

We are now 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- very good at night and poor to fair at day,

?

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

?

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

?

21000-21850 kHz- very poor at night and fair to good at day,

?

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

?

28000-29700 kHz- very poor at night and poor at day.

?

Excellent- S9+10 or >

Very Good- S9 +1-9

Good- S8-9

Fair- S4-7

Poor- S1-3

Very Poor- S0

?

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.

?

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

?

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).

?

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 at my new web page of

/g/w4hmradiowavepropagationforecast

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.


#99 Issued Monday April 9, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 67.8 67.9 68.4

There had been 20 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 0.

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

In 2018 there had been 60 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 1 0 1 0 1 2 2.

The 24 hour period maximum and minimum solar wind speed ranged between 361 & 344 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend April 9, 2018- steady state

HF radio wave propagation condition trend April 10, 2018- deteriorating

HF radio wave propagation condition trend April 11, 2018- deteriorating

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast g-

We are now 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- very good at night and poor to fair at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and good at day,

21000-21850 kHz- very poor at night and fair to good at day,

24890-24990, 25600-26100 kHz- very poor at night and fair at day,

28000-29700 kHz- very poor at night and poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 the realm of plasma 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.

/g/w4hmradiowavepropagationforecast

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.



#100 Issued Tuesday April 10, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 69.0 68.7 69.0


There had been 21 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 0.

There had been 9 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 61 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 to active geomagnetic condition of 2 1 3 2 2 2 2 4.

The 24 hour period maximum and minimum solar wind speed ranged between 572 & 470 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend April 10, 2018- deteriorating

HF radio wave propagation condition trend April 11, 2018- deteriorating

HF radio wave propagation condition trend April 12, 2018- deteriorating

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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 heliophysicist, terrestrial meteorologist/climatologist and one of the few on the planet with advanced education & 44 years of forecasting experience in both disciplines.

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 other 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 the realm of plasma 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.

/g/w4hmradiowavepropagationforecast

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.



#101 Issued Wednesday April 11, 2018 at 1430 UTC

Important Solar, Space & Geomagnetic Weather Indices-

The daily solar flux index numbers (DSFI) were 68.1 68.5 67.7


There had been 22 days in a row with a 2000 UTC daily solar flux index number (DSFI) below 70.

The official daily sunspot number (DSSN) was 0.

There had been 10 days in a row with a daily sunspot number (DSSN) of 0.

In 2018 there had been 62 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 to active geomagnetic condition of 2 4 4 3 3 3 2 3.

Today Wednesday April 11, 2018 the 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition to minor geomagnetic storming condition of 5 4 4 2.

The 24 hour period maximum and minimum solar wind speed ranged between 579 & 467 km/s.

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation condition trend April 11, 2018- deteriorated

HF radio wave propagation condition trend April 12, 2018- deteriorated

HF radio wave propagation condition trend April 13, 2018- steady state

Steady state means that HF radio wave propagation conditions are not improving or deteriorating.

Northern Hemisphere Radio Wave Propagation Forecast b-

We are now 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

Southern Hemisphere Radio Wave Propagation Forecast b-

We are now 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- fair to good at night and poor at day,

6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair at day,

13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at night and fair at day,

21000-21850 kHz- very poor at night and fair at day,

24890-24990, 25600-26100 kHz- very poor at night and poor at day,

28000-29700 kHz- very poor at night and very poor at day.

Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0

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.

And though this HF radio wave propagation forecast is produced based on the SIGINT_CAP, 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 around on every continent of the globe and tweak the forecast manually if and when necessary.

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).

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. 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.