Steve:
I tried an RF choke on the mic cable, and, although it reduced the RFI
somewhat, it did not eliminate it completely.
As a short-term fix, I may just try your solution with the additional ground
cable between the mic and the rig.
Kevin has sent me a very informative e-mail that summarizes the floating
ground issue with the Heil mic and its associated cable, especially as far
as Kenwood TS480's are concerned. It seems that the problem is related to
which version of the rig you have, and that can be determined by the rig's
serial number.
I'll check into this as soon as I can.
I already have written to Heil about the problem, so will see what they say
too.
Thanks to everyone for bearing with me through this whole thing. I now know
the problem, so the solution becomes easier.
73 from Tom Behler: KB8TYJ
----- Original Message -----
From: "Steve Forst" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, March 10, 2011 9:09 AM
Subject: Re: KB8TYJ 20-meter RFI problem solved, I think finally!
Good news Tom,
Just like being a drunk or drug addict, admitting the problem is the
first step to getting it solved. In your case, finding the source of
the trouble out of the multitude of possibilities is a big step.
If you have the same mic as i have, it has a cord about 8 ft. long.
Try winding up the excess into a coil, along with the ferrite. I
replaced my cable years ago with a shorter one that ends in a 1/8 plug,
so I can switch between headset and Gold Line very fast.
Just for the heck of it, you may want to try a ground wire between mic
and radio and see what happens. Either a jumper with clips, or loosen
the nut at the toggle switch and slip a wire under.
Now that I think about it, i remember Heil's web site explaining the
need to ground these things better, and to jumper one of the pins on
the 8 pin connector to the shell of the connector. I think the mic has
a floating ground that needs to be brought to chassis ground.
Maybe you will have a happy ending to "How I spent My Spring Vacation".
73, Steve KW3A
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