What does this mean: "I tuned using the gamma matches on the antennas the
best I could" Did you have trouble obtaining a 1:1 match? You can check
and adjust the impedance of a single antenna though coax that is a
multiple of 1/2 w.l. If the yagis are all good then there is something
wrong with your phasing system or you have some serious interaction with
something else on the tower. In the long run it will be much easier to
correct the problem than cover it up.
John KK9A
To: <towertalk@contesting.com>
Subject: [TowerTalk] Antenna matching values
From: "Drax Felton" <draxfelton@gmail.com>
Date: Mon, 21 Apr 2014 23:44:02 -0400
I have a phased set of four 2 meter Yagi's that I tuned using the gamma
matches on the antennas the best I could.
Now that the antennas are 90 feet in the air I have a slight SWR problem at
the input of the array and cannot load my 1kW solid state amp to full power
without it locking out.
I'd like to put a matching circuit at the input of the array on the tower
end to avoid feed line losses.
I need to know what fixed values of impedance, capacitance, and inductance
to put into two T match or other circuits to get nearer to a 1:1 SWR.
This is what my antenna analyzer says now:
When using horizontal polarization
144.100 MHz R=17 X=0 SWR 2.9
When using vertical polarization
144.100 MHz R=36 X=25 SWR 2.0
I know one of you is a good electrical engineer and can point me in the
right direction.
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