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Re: [TowerTalk] Remote Tuner with ZS66BKW or OCF Dipole

Subject: Re: [TowerTalk] Remote Tuner with ZS66BKW or OCF Dipole
From: Jim Brown <>
Date: Sun, 26 Jul 2015 22:41:16 -0700
List-post: <">>
Several thoughts. First, the open wire matching section is part of the antenna, and any noise pickup on it will be coupled to the antenna and show up in the receiver. Second, feeding any antenna off center greatly increases the common mode current and voltage, which increases the noise pickup. Third, antennas like this cannot be choked because the common mode voltage is too high AND the SWR is too high, both of which are likely to fry the common mode choke (the real name for a "current balun") if you're running much power.

These antennas were cooked up half a century ago when hams had never really run into serious RX noise and had never heard of common mode chokes. Yes, it is possible to make a dipole like this "work" on all bands, but as N6BT has shown by working all continents on a light bulb, almost anything "works." The questions are "how well does it work," and "are there other simple antennas that work better." The answer to the first is "not very well," and to the second, a well designed vertical on a roof or one or more multiband resonant fan dipoles will outperform it. The vertical may be equally noisy, but the fan dipoles will be much quieter because they can be effectively choked.

73, Jim K9YC

On Sun,7/26/2015 8:07 PM, Phil Coley wrote:
I have read a lot on these antennas from post on the web on their "pros & cons". There isa lot of 
info on the web regarding loss with certain types of coax, types of ladder lines, varyinglengths for better 
band coverage (OCF), etc.I know that many G5RV/ZS6BKW versions say that at least 70' of coax must be used for 
the antenna to workproperly. And the SWR on some of the bands with both the G5RV/ZS6BKW & OCF have an SWR 
that is toohigh and losses would make the band "non-useable" due to this.Has anyone experimented with 
using a remote Tuner (LDG, MFJ, etc.) near the antenna to reduce losses inthe coax to the rig?  What would be 
the results in say, using a remote tuner on a ZS6BKW after the ladder lineconversion to a SO239 for coax? The 
need of an balun/CMC choke would probably be helpful & maybe a shortrun of coax before connecting to the 
tuner? If a low SWR is obtained at the remote tuner, my thinking is the loss on the coax run to the shack would 
be verylow. This would be h
elpful especially on a long coax run. Am I "out in left field" on my thinking? 
Is this a workablesituation or are there factors I am not seeing?Phil K4MPE

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