[TenTec] [Ten Tec] OCF Antennas - Which commercial antenna is gest?

Steve Hunt steve at karinya.net
Wed Sep 23 07:37:01 EDT 2015


A possible explanation - and from my experience the most likely one - is 
that your "antenna" was actually the braid of your coax, top-loaded by 
the OCF wire. The differential-mode impedance of a 130ft wire fed at the 
25% point is so high on 160m it's almost impossible for any choke/balun 
to prevent CM current on the braid. You'd only need about 30ft of coax 
for that system to appear as a top-loaded 160m quarter-wave.

Steve G3TXQ

On 23/09/2015 11:21, Joe Papworth via TenTec wrote:
> Maybe you can explain why an ocf antenna I once had worked on 160. I called it "My accidental 160 meter antenna."
> It was a full wave on 40, (i.e. 130 ft) and fed with coax, 1/4 wave in from one end. I intended to use it only on 40 but I discovered it was resonant on 160 also.
> Any idea why it worked? Or was it just pure luck?

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