[ICOM] Receive level dropping-rig or antenna system issues?

[Larry Young]

John: It should be easy to determine if it is internal or external to the rig. When the  receive is normal, attach an external signal source to the antenna input and note its level on the S meter. When the receive level drops, reconnect the same signal source and again not the S meter level. If it is the same as before when good, then obviously you have some oxidation occurring somewhere in the antenna/feedline/balun path.
Larry  K4LXV


--- On Sun, 3/24/13, John G. <af5cc at fidmail.com> wrote:

From: John G. <af5cc at fidmail.com>
Subject: [ICOM] Receive level dropping-rig or antenna system issues?
To: "ICOM Reflector" <icom at mailman.qth.net>
Date: Sunday,
 March 24, 2013, 3:03 PM

Here is a message I posted a few months ago about the receive level dropping off at times in my Icom 706 original:

"I have noticed for the past few months that the receive seems to drop
at times on certain bands-it started on 12m and now occurs on 15m as well. If you click the key or mic to quickly put it into transmit the receive comes back. To me this sounds like a dirty relay or one that is going bad"

Now here are some additional details, it seems to be occurring on other bands as well. 17m at times, and was doing it on 30m last night. Someone suggested to me that it could be a problem in the antenna system as well. I did some checking this morning, and have determined that it isn't in the low pass filter, the MFJ tuner, or any jumper coaxes in the shack. It would have to be in the feedline going to the G5RV, or the balun there. I haven't had time to change out the coax run
 yet.

I have also noticed that on 12m and 15m the receive will come back up by itself at times. Sometimes it is a quick drop down and come back several times in succession. Would a relay problem do this?

So, with this latest information, what is the better guess as to the problem-in the rig or the antenna system?

73 John AF5CC

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