Topband: Coax Shield vs. Ground & elevated radials

Björn Mohr bm at
Tue Jan 2 11:00:33 EST 2007

>> I will try the coax choke at the next opportunity to see if I notice any
difference. <<

Update: I added the choke at the antenna base. Before doing that I created a
probe by wounding abt 15 turns of enamelled wire around the coax close and
localised a point on the coax with a maximum reading close to the shack
where I measured 2.5 volt with a 10 watts carrier before adding the choke.
After adding the choke I measured 4.4 volt at the same point. My assumption
was that the problem got worse, not better... But less TVI reported so I
guess that's at least one step in the right direction.

Resonance seems to have changed abt +4kHz, but everything else seems normal.

I am not sure if work better or worse now, but I will try the setup tonight
to get a feeling for its performance with the choke.

73 de Björn /SM0MDG

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