Generally
coils are used to make an element electrically longer than the physical
length.? Several designs are physically tuned to 10 meters.? coils make
them resonate on 12, 15, ...?
Generally
transformers are used to convert impedance. An electrically short
antenna usually has a low input impedance at resonance.? A transformer
might be used to increase that to 50 Ohms.
A clever person could design an antenna that combines both functions into one unit.
On Thursday, September 19, 2024 at 10:36:05 PM PDT, David via groups.io <dkvarn@...> wrote:
Nice article, IMO well-written with nice pix. One aspect I would like to better understand is the distinction between loading coils (e.g., Ranger 80, Super Antenna, Wolf River) and transformer (e.g., Chameleon MPAS Lite). Opinions? Pros/cons? Use with antenna tuners?
Nice article, IMO well-written with nice pix. One aspect I would like to better understand is the distinction between loading coils (e.g., Ranger 80, Super Antenna, Wolf River) and transformer (e.g., Chameleon MPAS Lite). Opinions? Pros/cons? Use with antenna tuners?
As a few of you know I am in Yellowstone National Park for a week. We arrived Tuesday night and had two flights that were memorable, and not in a good way.?
?
The flight to Salt Lake City started out fine until I heard someone yelling ¡°Larry Larry, Larry, Wake Up Wake Up!¡± I couldn¡¯t tell where the shouting was coming from but soon a woman pressed the flight attendant button and someone came to assist her. The man, I¡¯m guessing Larry, was sitting in his seat and unresponsive to the yelling and punching of him. Either the wife or the flight attendant said ¡°Is he dead?¡± Well, I guess Larry heard that and suddenly woke up. His wife said he had taken a dramaminebefore the flight and it had made him sleepy. So everything turned out find for Larry.
On the second leg of the flight to Billings we were warned of a bumpy ride so we had our seat belts on for almost the entire flight. About 20 mins before landing the captain made an announcement that there might see more turbulence and asked the flight crew to take their seats. I didn¡¯t really think anything of it until we hit a huge pocket of air and suddenly there was a tremendous boom and the plane made a steep dive down and a roll to the left¡¡kind of like a roller coaster that I never wanted to ride. The passengers were all strapped in, some more tightly than others and I could see people coming up out of their seats as the plane did it¡¯s ¡°dive and roll¡± motion. No-one was thrown out of their seats, thankfully. This happened twice. We landed safely and everything was good. I think Larry would have woken up with the dive and roll on this flight.
?
On a better note. The friend¡¯s house I am staying at is in Gardiner, MT just outside of Yellowstone park. It¡¯s up on a hill looking? the town and the altitude is about 5700 ft. I was able to park the car on a roll up mast holder my husband built and operate right from the driveway very close to the down slope of the mountain their house is on. I think today may be the only day I will be able to operate so I did it even though it rained, no thunder, all day.? I was able to chase a lot of parks on the air activators in PA, NM, CO, TN, AZ, MN,MA,WI,I,CT,MI,MS. Tomorrow the weather is supposed to be much better for the remainder of our stay. I hope to go to the Bear Tooth Highway which is just a few miles from the other house I will be staying at outside of Yellowstone. We had a winter weather warning last night and the Bear Tooth highway was closed but it should be opened soon. I plan to use the drive on mast board again on a pullout. The altitude is 9,947 ft and I have a tee shirt I brought to prove it. I did not bring oxygen with me, but I will have bear spay¡..But it¡¯s so high the bears don¡¯t even go there.?
?
PS. I was able to get a few more POTA stations when I operated this morning, NY, NC, FL AZ,OH, and Ontario Canada. Not sure I¡¯ll be able to operate much more.? Here is a couple of photos of where I was operating from.?
Whether you¡¯re a seasoned
ham or buying your first
antenna, choosing the right
one is more about how you
operate as an individual and
less about the antenna¡¯s
capabilities. ,
I¡¯ve explored field antennas
and the decision-making
process behind choosing the
right one. I believe that a
practical understanding of
your operating style is key
to making the best choice.
This article is about
vertical
antennas¡ªspecifically, those
designed to be portable and
stealthy. These antennas are
ideal for field operations
like POTA, SOTA, or IOTA,
and for those living under
HOA restrictions that
prohibit permanent antennas.
(Image/Thomas
Witherspoon, K4SWL)
There are hundreds of
vertical antennas on the
market, and it¡¯s beyond the
scope of this post to cover
them all. Instead, I¡¯ll
focus on three models I¡¯ve
personally used, each
representing different
concepts and reasons why you
might choose one over
another.
All of these antennas are
multi-band, and while some
can be installed permanently
with proper sealing, they
are primarily designed with
portability and ease of
setup in mind.
Before diving into the
specifics, consider these
questions as you search for
your next antenna:
What modes and
power levels do you
intend to operate?
Ensure your antenna can
handle the wattage and
duty cycle of your chosen
mode (SSB, CW, Digital).
For example, an antenna
that handles 100 watts SSB
may not be suitable for
100 watts FT8.
What bands do
you plan to operate?
Confirm that the antenna
covers your preferred
bands. Portable verticals
are effective on 20 meters
and above but become less
efficient at lower
frequencies due to the
need for loading coils to
electrically lengthen the
radiating element. This
compromises performance
and decreases operating
bandwidth. However, I¡¯ve
had great success on 80
meters with some portable
verticals, though they are
less efficient compared to
longer wire antennas.
How far do you
plan to hike with this
antenna? Check
the specifications for
weight and element
lengths, as these factors
will impact your comfort
and the feasibility of
carrying it in your pack.
How important is
frequency agility?
If you primarily operate
FT8 and stay on one
frequency for extended
periods, any antenna will
likely suffice. If you
frequently move across
bands to chase activators
or DX, consider an antenna
that doesn¡¯t require
manual tuning.
***
Three Types of
Portable Verticals
Here are three vertical
antennas I¡¯ve used in the
field, along with their pros
and cons:
***
1.
Quarter Wave Verticals
One of the simplest
vertical antennas is the
quarter wave. My first
quarter wave antenna was a
5-meter radiator wire
(one-quarter the length of
20 meters) with four
counterpoise wires on the
ground. I attached the
radiator to the center of my
coax and the counterpoises
to the shield. I¡¯ve deployed
the radiator vertically in a
tree (great for permanent
setups) and supported it
with a fiberglass
telescoping fishing pole
(ideal for portable use).
While these antennas are
simple to build, I prefer an
antenna that works on
multiple bands and is easy
to deploy and pack. This is
why I¡¯m a big fan of the .
The MC-750 is a portable
vertical deployed using
either a stainless ground
spike or a tripod. The
vertical element is a
stainless steel whip with
silk-screen markings that
help you deploy the antenna
for resonance on multiple
bands.
(Image/Thomas
Witherspoon, K4SWL)
When I follow the
silk-screen markings and all
four counterpoise wires
(attached to the base), I
consistently achieve a near
1:1 SWR. Thus, no ATU is
needed. The SWR remains
consistent across various
topographies.
The
Chelegance MC-750 comes
with jacks to install four
included preassembled
counterpoise radials.
(Image/Thomas Witherspoon,
K4SWL)Chelegance
MC-750 carrying case
(Image/Thomas Witherspoon,
K4SWL)
The MC-750 ships with a
coil for 40 meters.
Chelegance also offers an
optional
as well.
Pros:
Easy deployment, high
quality, efficient,
multi-band use with no ATU
needed, resonates on 20-10
meters and 40/80 meters
with coils, comes with a
custom padded carrying
case.
Cons:
Not truly a con, but you
must adjust the whip
length when changing bands
if not using an ATU.
***
2.
Verticals with
Transformers
Chameleon
CHA MPAS Lite Modular
Portable Antenna
(Image/Thomas Witherspoon,
K4SWL)
If you regularly use an
antenna tuner in the field,
you might prefer a
high-quality multi-band
vertical antenna equipped
with a transformer to reduce
potentially high impedances
to a level manageable by
most tuners. I think of this
type of antenna as the
vertical equivalent of a
random wire antenna. Many of
my QRP transceivers have
internal ATUs, making this
type of antenna very
appealing. The one I have
the most experience with is
the .
Like the MC-750, the MPAS
Lite uses a stainless steel
whip but includes a
transformer at the base,
making it easier to match
the antenna across multiple
bands with virtually any
ATU. Additionally, it can
operate on lower bands,
including 80 meters, without
needing a loading coil
attached. While not as
efficient below 30 meters,
it remains highly effective
for both POTA and SOTA where
you are often the DX.
The MPAS Lite offers
excellent frequency agility,
which is a major advantage
if you frequently hunt or
chase other stations in the
field. Just change the
frequency, activate the ATU,
and you¡¯re set.
(Image/Thomas
Witherspoon, K4SWL)
The MPAS antenna can also
be configured as an end-fed
random wire using the
counterpoise wire. Consult
the MPAS Lite manual for
multiple configurations.
Pros:
Easy deployment, high
quality, multi-band use,
frequency agility, only
one counterpoise,
versatile platform for
multiple antenna
configurations.
Cons:
Pricier than the MC-750.
***
3.
Loading Coil Verticals
I¡¯ve used several antennas
with helically wound coils
and a sliding tuning coupler
at the base to match the
antenna across multiple
bands. The coil at the base
shortens the antenna
electrically, making it
portable and low
profile¡ªideal for stealthy
use or in neighborhoods with
aggressive HOA restrictions.
Among the many coil
antennas available, the new
stands out for its
robustness. I was impressed
with its ease of setup, high
quality, and smooth tuning
coupler. The REZ Ranger 80
antenna also handles higher
power than other coil
systems¡ª100 watts CW/digital
and 200 watts SSB.
REZ
Antenna Systems Ranger 80
HF Portable Antenna System
(Image/Thomas Witherspoon,
K4SWL)(Image/Thomas
Witherspoon, K4SWL)
The Ranger 80 is quick to
deploy and incredibly
durable. While I¡¯ve never
been a big fan of verticals
with loading coils and
sliding tuning couplers, as
they can be finicky to tune,
I found the REZ Ranger 80 to
be the best of the bunch and
more forgiving than others
I¡¯ve used.
(Image/Thomas
Witherspoon, K4SWL)
Pros:
Easy deployment, superb
quality, higher power
handling capacity,
multi-band resonance, no
ATU required.
Cons:
Heavier than other
options, tuning coupler
needs adjustment for each
band change, pricey.
***
Summary
Choosing
is more about matching your
equipment to your specific
operating style than simply
selecting the most capable
model. Whether you
prioritize ease of
deployment, frequency
agility, or power handling,
the antennas discussed¡ªlike
the Chelegance MC-750,
Chameleon CHA MPAS Lite, and
the REZ Ranger 80¡ªoffer
distinct advantages that
cater to different needs.
Before making your
decision, consider the
nature of your operations.
Are you regularly chasing
signals across multiple
bands, or do you prefer to
set up and stay on one
frequency? Do you need a
lightweight, portable
solution for long hikes, or
are you more concerned with
stealth and ease of use in
restricted environments?
Your answers will guide you
to the right antenna.
Ultimately, the best
antenna is the one that
enhances your enjoyment of
the hobby, allowing you to
operate confidently and
efficiently in your chosen
environment. If possible,
try before you buy¡ªborrowing
from friends or club members
can provide valuable
insights that specs alone
can¡¯t offer.
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Hey folks, Saw this today.? Wish the writer had cited the study.? So, informal poll:? does this match your experience,?
> We also know that hotter temperatures impair our productivity. A naval officer makes an average of 11 or 12 mistakes per hour in translating Morse code when the temperature is between 85 and 90 degrees, a British study found, but 95 mistakes per hour when the temperature rises to 105 degrees.
()
I had fun today with ARRL VHF contest.? Over a dozen QSOs on all bands 2m to 23cm, in an hour.
Tomorrow, we're running radio telegrams from the SS ROV, for Pancake Breakfast event.? 40m.
Over lunch, David was talking about a trip he will take soon.? He also was disappointed that the trip has been re-routed away from crazy people with missiles, so he won't go the Red sea or the Suez Canal.? In particular he will miss Luxor.
I'm booked for a trip to Egypt in 2027.? The "main event" will be a solar eclipse amongst the Pyramids.? Most of the trip will be on a cruise on the Nile, with good hotels before and after.
Insight Cruises is the same travel agent that did my eclipse trip this April. For that one, they booked with Holland America.? They also had a series of lectures by astronauts and astronomy professors. Also head staff from Sky and Telescope.? There will be a similar option for the Egypt trip.
Here is a recent email, in case you want to see Luxor, the Pyramids, etc.
Dear Paul,
I wanted you to know that we have recently added a new OPTION nearly
identical to your current booking -- but in the reverse order.
OPTION 11, on the very luxurious AMA Dahlia, sails from Cairo to Aswan.
Here's the AMA Dahlia itinerary:
Here's info on the ship:
Here is your current itinerary:
If you would like to move, there are no penalties or fees; all of your
payments would be moved over to your new booking.
WE ALSO recently added OPTION 10, which is a 9-night Nile River cruise
from Aswan to Luxor. This OPTION is also on a luxury ship.
I enjoyed reading last evening Hiroki's article about creative antenna design in the September issue.? My only complaint is that he doesn't claim to repurpose the contents of those coffee cans like he does potatoes.
David
David W Crocker
Cliff Sojourner K6CLS