Not necessarily true, Wayne.
CMC can have several sources.
Adding a choke at the feedpoint only helps if the antenna itself is causing
an imbalance - due to whatever...
If your coax is not running perfectly 90 degrees away from the antenna for a
quarter wavelength or more, it can pick up common mode current (CMC) as a
result of direct radiation into the coax. In that case - and in every case,
a choke at the house is necessary.
BEST CASE: use two, one at the feedpoint and one at the house.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of
k4elo@fastmail.fm
Sent: Sunday, June 01, 2014 6:43 PM
To: tentec@contesting.com
Subject: Re: [TenTec] Trading radios
Disagree Bob. Put the choke at the feedpoint of the antenna or your coax
will be radiating rf all the way down to the rig. If you can't move the
antenna, this is the most effective rfi fix.
73
Wayne
K4ELO
> For starters, as to RFI issues, yes antenna to radio spacing,
> increasing same, will usually improve the issue. Be sure all equipment is
each
> bonded to a common point such as the PS ground. Omit the external
> ground but keep 3rd pin ground intact. Use a common mode choke on the
> output of the radio.
>
> 73
> Bob K4TAX
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