EDWARDS, EDDIE J EDWARDS, EDDIE J" <eedwards@oppd.com
Tue, 6 Jul 1999 08:49:28 -0500

Dave Jordan [SMTP:wa3gin@erols.com] wrote:
> on 75m SSB one work kills the engine.  I have not
> solved this problem.  However I did discover by accident that there is
> significant RF on the control
> cable running from the transceiver to the control head of the FT-900.
> While testing on 75 I got an
> RF burn from the ground side of the speaker output on the back of the
> FT-900 remote control head.  Somehow the control cable is picking up all
> kinds of RF. WHen I ground the control head speaker ground the receive
> audio is now unindated with alternator whine.
Does the control cable have a ferrite choke on it already?  If not, I'd try
adding one or more to see if that helps.  If the RF on the cable is common
mode, a ferrite will attenuate the common mode currents.  Any control cable
in the presence of RF should (or must) have a common mode RF choke on it.
Try adding some ferrites to the power cable also since it is such a very
long run from the battery to the radio.

If none of these help, move on to the brute force filtering in addition.

GL & 73,
de ed -K0iL

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