Bill:
Vertical antennas at low heights are usually noisy, and have
a low (average) angle of of radiation. The latter is great for
DX not not so much for shorter skips. Better conditions will
help all antenna issues to some extent. End feds operating at
a full wave length have terrible radiation pattern, e.g. zero
at zero elevation (not height above ground). End feds work
best at 1/2 wave, I guess 40 mtrs. in your case. The successful
end fed verticals work best at odd multiples of 1/2 wave. So
you see a lot of end fed J-poles for 2m. and 75cm. The fed
point impedance is usually set for the 1/2 wave case so the
SWR may be lowest there.
73, Gary
On 4/9/2021 4:49 PM, Bill Hornbeak via BVARC wrote:
I sadly purchased the above antenna, hoping to be able to have a
little better reception/transmission than I currently have. My area is
restricted, with only a backyard (20'x50') available. There's a huge
live oak situated in the center and two feet from the fence which
doesn't help with deployment. Ground radials are not feasible.
The antenna as per spec provides a very low SWR across all bands
without a tuner. There are background noises from 160m to 20m at
which point it goes deaf and mute 17m to 6m. On the Monday night 10m
net I can barely hear or be heard by a HAM about 5 miles away.
So if any of you adventurous souls have a hankering to try something
new as soon as I've replaced it (very soon) it will be available to
try out. Just contact me.
Notes:
1. Recommended height is 35' and I have it at 20', manufacturer's
email (available) told me that even at 20' it should respond better.
2. Same email from the manufacturer indicated it uses the coax shield
and recommended 50' to 100'. So I added length and found no changes.
3. Decided to try 4 radials 12' to 15' long attached just below the
coax termination and stretched out (angled down), also resulted in no
changes.
Bill - K5GJQ
--
vs: Habakkuk 3:17-18
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