[amsat-bb] Homebrew Up-Dated Eggbeater Antenna
tommypnq at centrum.cz
Wed Mar 16 08:27:53 UTC 2016
I have built this antenna both for VHF and UHF years ago, I am using now
just the UHF version for the NO-83 and NO-84 monitoring. I have mounted
the LNA on mast just below the antenna and in the shack I have splitter
for two SDRs to automatically record every pass. The sats can be seen in
the waterfall from horizon to horizon, for the decoding of beacons I
need some 5-10degs elevation. The crucial point of the setup is low
noise background = I have it deployed at home in small village. I tried
it in the city, but the SDRs AGC where pushed some 20dBs by ISM signals
and there were just overhead traces from the strongest sats.
So do the experiment and you will see.
Dne 15.3.2016 v 19:50 Robert Bruninga napsal(a):
> NO84 is only 300 mW compared to 2W for the original PCSAT and 5W for the
> ISS (currently). You need gain to hear it...
> If you want a non-moving fixed antenna to hear NO84, I'd try a 58"
> vertical whip over a large metal ground plane. This would give you up to
> 7 dBi above about 30 degrees. Then you would hear it every day, but only
> for the better passes above 25 degrees. But you would hear it then.
> And I modeled it in EZNEC and just a vertical over say 4 radials is not
> the same thing. That helps matching, but does not block the 3db part of
> the pattern into the ground. You need a real "ground plane" of a metal
> roof, or about 6 feet or more of chicken wire.
> Easy for me to say, because I have not built one yet...
> Bob, WB4APR
> -----Original Message-----
>> Bummer! I'm looking for some sort of an Omni ant to use with NO-84
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