On 3/9/2019 7:13 PM, Michael Walker wrote:
You may want to try choking the feedline at the antenna
Always a good thing.
and more importantly at the amp end
No, the FEEDPOINT is the most important place for the first choke in any
antenna system. The purpose of a second choke on an antenna like a
dipole is to prevent it from acting as a parasitic element to a nearby
vertical.
with mix 31
Yes.
or 43 chokes.
I've recently completed a year's worth of extensive lab work that has
convinced me that #43 is NOT a good material for HF chokes. Ditto for
the #52 material that G3TXQ recommended. Two characteristics combine to
make it a poor choice. First, it's a relatively high Q material, so the
resonance it produces can get very narrow. Second, like all Fair-Rite
parts, it's a wide tolerance part -- +/- 20%. A part at the low end of
the tolerance range will produce a very different choke (resonance in
the wrong place, very narrow bandwidth, wider resonance and not high
enough impedance.
That work has produced, among other things, an all new cookbook with
greatly improved designs. k9yc.com/2018Cookbook.pdf
As to Peter's problem -- I'm inclined to agree with Don that something
may be arcing in the antenna system and causing a true fault.
73, Jim K9YC
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