[UK-CONTEST] Rf in 'mp audio

[Don Beattie]

John,

I've had this with both the FT1000D & the MP range.

What I found was that it was one of the rear plug-in leads (can't remember
which) bringing rf into the rig. Suggest you try a clip-on ferrite choke on
each in turn (key, band data etc etc) It fixed mine, but since being here
(with antennas 100m away) the problem has gone away.

But from your description is does sound as it it's the headphone lead in
your case - again a clip-on choke may help

Good luck

Don, G3BJ



-----Original Message-----
From: uk-contest-bounces at contesting.com
[mailto:uk-contest-bounces at contesting.com] On Behalf Of John Wayman
Sent: 20 October 2010 21:39
To: UK contest list
Subject: [UK-CONTEST] Rf in 'mp audio

Hello,
I am hearing a huge thump in the headphones on the first character when I
send CW on my old-school 'mp. It seems as if it kills the AGC, which then
recovers after the first dash, or thereabouts. Funny thing is, it does it
the same whether I use the sidetone or the monitor.
No such problems if I use the built-in speaker, or if I connect an external
speaker to the rear panel. Just the headphone socket.
Have you seen anything similar, and, if so, how did you cure it?
I am not aware that I have changed anything, or done anything I can point to
as having made a difference.

I wonder whether it could be related to the well-known intolerance of RF
with a key plugged into the front panel key jack (I just never use it these
days), although I don't see how.

What I want is for someone to say 'You just solder a 0.01 across these
points and it will be fine.' I don't think life is like that, though, is it?

Any advice gratefully received (except trading it in against an FT2000, or
5000, or whatever!)

In the meantime, I'll have a look at that part of the circuit diagram.

73,

John
G4DRS
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