[TowerTalk] Fwd: Fwd: effect of two wire antennas end to end

[Hans Hammarquist via TowerTalk]

if you try to put a common mode choke at the antenna I can imagine difficulties with overheating etc as the voltage is high. I allow the unbalance current through the feeder and I stop it after the tuner.


A well design (unlike mine) Windom, or Off-Center-Fed antenna has a resistive 200 - 400 ohm impedance at the feeding point allowing for a balun at the feeding point and a reasonable SWR in a coax feeder. I will not recommend what type of balun to use but imagine that the "right' balun reduces any common mode current outside the coax.


I have not problem with overheating maybe my 100 W is one reason.


Hans - N2JFS



-----Original Message-----
From: Jim Brown <jim at audiosystemsgroup.com>
To: towertalk <towertalk at contesting.com>
Sent: Wed, Feb 25, 2015 1:27 pm
Subject: Re: [TowerTalk] Fwd:  effect of two wire antennas end to end


On Wed,2/25/2015 10:17 AM, Tom Osborne wrote:
> With both legs being different length, wouldn't there be an unbalance 
> in the feedline? 

YES!  Which makes them subject to noise pickup. And which makes them 
difficult to choke -- the high common mode voltage fries the choke.

73, Jim K9YC
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