[UK-CONTEST] RF Feedback

[Andy Cook, G4PIQ]

Stewart,

I've had enough problems with RF feedback into an MP - try adding a few
thousand pF across from mic to ground at the radio or even some of the
midway connections - fixed stuff for me.

Andy

-----Original Message-----
From: Cooper, Stewart [mailto:coopers at odl.co.uk] 
Sent: 06 October 2003 09:50
To: uk-contest-X-contesting.com-POP-1 at mail-x-change.com
Subject: [UK-CONTEST] RF Feedback


In setting up my station for this year's CQ WW SSB I have discovered
that my constantly tripping Alpha 91 is caused by RF feedback getting
into the Heil mic. It's not a problem that is immediately obvious on my
transmitted audio. In fact, no one has ever mentioned anything, and it
is worse on some bands
(10m) than others. What I need is some real world practical advice to
eliminate the problem. Perhaps that advice might help others with a
similar problem. I use a Heil ProSet headset with a DX Doubler, MFJ 432
DVK and FT1000MP. Now, the DX Doubler doesn't appear to add to the
problem and the MFJ might appear to, but I run it on internal batteries
and the problem remains even when it's out of circuit. I use a ferrite
toroid on the headset mic cable before it enters the DX Doubler. I have
tried earthing all the components in the shack to the same earth 'bus'
although this (for audio
equipment) might not be a good idea. Any other suggestions? Mail me
direct if you feel this is not contest related enough. Response may be
slow. I'm /5B4. 73

Stewart Cooper 
GM4AFF/GM0F