Tom,
It sounds like you have an impedance mismatch when the preamp is out of the
circuit. If your audio is good with the preamp on, why not just leave it
that way?
Steve
----- Original Message -----
From: "T Behler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, October 18, 2008 21:05
Subject: status update on MC60 problem with TS480
> Hi, all.
>
> Well, this evening, I made the ground connection that has been discussed
> as
> a way to solve the RFI problem with the MC60 mic, when used with the
> TS480.
> I screwed one end of a 14-gauge piece of wire to the base of the mic, and
> the other to the ground screw on the TS480 using spade lugs.
>
> I did a test on 75 meters, which seemed to be the band where the problem
> had
> been most apparent, and it looks like I might have solved the problem.
>
> However, the people I talked to said my audio needed more base, so I may
> still have to work with the TX equalization settings on the 480 to see
> which
> setting might sound best. Right now, I have the TX equalization set to
> "off".
>
> I did notice one interesting thing, though.
>
> Even with the new ground connection, my audio gets much worse when I
> switch
> the pre-amp to "out". If it is "in", I get good audio reports. Wouldn't
> the "in" setting mean the pre-amp is in the circuit? Why would my signal
> get worse with the pre-amp "out"?
>
> Still learning here, obviously.
>
> 73 from Tom Behler: KB8TYJ
>
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