Are you still using the Comet
CHA-250B Carl and Kevan are absolutely right as to where to
spent your efforts. An antenna other than the CHA-250B aka
"antenna dummy load" would do wonders. Even Comet, in there
advertise, recognizes the CHA as mostly a radiating dummy load.
"Yes, some of the RF that enters the
power feeding section is turned into heat rather than
transmitted as RF, but that is one of the compromises needed to
create a broad-band, low SWR, multi-band HF antenna with minimal
The way they are able to create a broadband vertical is with a
lossy transformer. In their "matching transformer" a very wide
range impedance on the secondary is NOT accurately transformed to
the primary thus maintaining the 50 ohm load.
One possible solution would be a
Hustler 6BTV vertical. At Schofield middle school for SCR we used
a Huster 6BTV with good success. Even with a very modest temporary
ground system it did well. As a single aluminum pole the visual
impact is minimal. If necessary the Hustler can tilt mounted to
hide it when not operating. DX Engineering sells the 6BTV for
On 6/30/2021 7:19 AM, Kevan Nason
likely have a good reason for wanting 250 watts maximum, but
I'm having a hard time understanding why you are willing to
spend so much money for such little power increase. That is
assuming you are using 100 watts now. Carl's suggestion of
improving your antena seems a much better route -- whether it
is to get a hex beam OR improving your vertical's performance.
Especially since a hex beam would give you improvements on
both transmit AND receive.
the risk of stating the obvious... Going from 100 watts to 250
watts is basically a 3 dB improvement in your transmitted
signal. That helps, but mostly only if you are chasing weaker
signals like the DXers and Contesters do. Many newer rigs have
S meter calibrations of 3 dB per S unit. Older rigs have 6 dB
per S unit. Your desired amp will only give a 1/2 to 1 S unit
increase in signal for the other guy. You won't make a lot
more contacts with that little of an increase. Think of how
little difference you see when someone calls you with an S5
signal and while they are talking you see the meter "jump" all
the way up to S6. It just doesn't make much of a difference.
Is that worth the money? Not for me. And it's my experience
from attending dozens of Field Days that most people just skip
over those very weak signals where that one S unit improvement
would make the difference. They just don't want to make
the effort to dig the other station out of the noise. I'm not
an FT8 guy, but I doubt it will mean a ton more contacts in
that mode either. You'd likely get much better performance
from a Hex due to its directionality. True, a Hex doesn't do
40 or 80 meters, but the high bands are rapidly coming back.
If you're looking at 40/80 then I would focus more on better
low band antennas. In fact, that is the route I took here at
my own station. By improving my 40/80/160 meter antennas I've
seen a dramatic improvement in my ability to work stations --
without buying an amplifier.
8BDXCC, 314 countries confirmed (mixed current)
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