[Icom] Strange IC-765 40 meter problem

[Adam Farson]

Joe,

You can eliminate the IC-765 as the cause by transmitting into a dummy load,
and by checking the receiver sensitivity over a period of several hours with
an RF signal generator (if you have access to one).

I agree with Matt - a corroded or oxidised antenna component or connector
may be the cause.

Best 73,
Adam, VA7OJ/AB4OJ
North Vancouver, BC, Canada
http://www.qsl.net/ab4oj/
Note new e-mail address:
mailto:farson@shaw.ca



-----Original Message-----
From: icom-admin@mailman.qth.net [mailto:icom-admin@mailman.qth.net]On
Behalf Of Joe Stepansky
Sent: Sunday, July 28, 2002 03:44
To: icom@mailman.qth.net
Subject: [Icom] Strange IC-765 40 meter problem


For brief background, I began noticing something interesting with my
IC-765's performance on 40 meters earlier this year.  The receive level
would occasionally reduce considerably and suddenly (i.e. one second the
band sounds normal, the next it's severely attenuated).  After hitting the
keyer, even briefly, everything returned to normal.  I noticed this
happened more in windy conditions than not, so assumed it was my 40 meter
beam.  Also noticed that sometimes the SWR would go up to 3:1, then back to
a more normal 1.4:1.

Decided to replace the balun and coax on the beam.  Also checked everything
else out while we were up there.  All looked fine.  Came back down, fired
things up, had a 1.2:1 SWR.  Stations sounded fine.  Then the receive
problem kicked in again, and the SWR is now > 3:1!!

Is it possible this is something with the 765??  Has anyone seen or heard
of this happening?  It's so bad that even the antenna tuner won't knock the
SWR down.  I don't have another rig to test it with, so now I'm
stumped.  But we've replaced virtually everything that can be replaced on
the 40 meter beam, so I'm now out of ideas.

Any suggestions will be more than welcome.

73, Joe KQ3F