Russ,
The balun on the TH7 often fails (shorts between the wires). They
have a higher power balun. In the mean time, I'd coil up some RG8
Coax, perhaps 6 or 8 turns on a 6" diameter for a substitute balun.
Measurements without the balun could be meaningless.
The most common problem with HyGain traps is bees or bugs building
nests inside the traps. Sometimes it can be spotted by material
sticking out of the drain holes.....which I hope are facing downward!
They maybe cleansed out and reassembled. Since 20 meters is working,
the continuity of the trap inductors seems to be OK It's the bees or
bugs are not there, the capacitor aluminum cover or the plastic end
caps that maybe the problem. Also, sometimes the ground on the trap
can breaks loose. A close inspection of all traps is necessary!
73,
Joe, W1JR
At 08:47 PM 8/29/2005, Rnlamm@cs.com wrote:
>I first noticed that my TH7DX was not hearing as well as my other 15m
>antennas. The TH7DX does not resonant on 10/15m but works fine on
>20m. SWR at the ant
>is >3/1 from 21.0 to 21.9mhz, then decreases to 1.7/1@22.3mhz and back to 3/1
>at 22.9 mhz. On 28mhz: SWR is 2/1 from 28.0 to 29.0mhz. The balum was removed
>to collect this data. Does anyone have a systematic approach to determining
>which trap or etc is the source of the problem. Hygain tech support was of
>little assistance. Thanks in advance for your reply.
>
>Russ - NN3Q
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