[Kenwood] RE: TS850 micphrone problems

[Hsu, Aaron (NBC Universal)]

Hi Brian,

On both my TS-850's, "squeal" while using a mike normally means RF is
getting into the mic inputs - either the mic itself or the cabling is
picking up stray RF in your shack and causing feedback.

I had this problem, primarily on 20M.  Low power (low gain on the mike)
was OK, but once I got the power peaks past 50w, transmit audio would
distort or there would be a loud squeal that wouldn't stop until I
released the PTT (ala audio feedback).  No such problem on CW.  My
solution was to add .01uF bypass caps (small 50v monolythics are fine)
between the MIC+ to chassis ground and MIC- to chassis ground.  One
common error when wiring your own mike is to connect the microphone
leads to MIC+ and chassis ground - always led to RF problems for me, so
make sure to keep the MIC leads "balanced" (not connected to chassis
ground).

For reference, I uses the Heil ProSet with both HC-4 and HC-5 elements
with no problems after adding the bypass caps.  I also have a trusty
Shure 444D that works well.  I still have RF in my shack (due to
proximity to the antenna), but no more RF squeal during transmit.
Everything is also fairly well grounded (as best I can do), so no
problems with RF "bite".

73,

  - Aaron, NN6O


-----Original Message-----
Sent: Monday, March 27, 2006 4:36 PM
Subject: [Kenwood] TS850 micphrone problems 


Hello to the group, I discovered tonight that I'm having some sort of
problems with radio. Since I'm new to a 850, is there anything I should
look for.

I had been for the longest using a Radio shack headset with boom mic and
that finally bit the dust then I go get a Heil and all I get is a squeal
using that setup, sent the Heil back for possible repairs, now I hook my
MC-60 up and sometimes the mic works sometimes it don't.

Now I'm thinking I'm having some sort of radio problems.

Any suggestions on what to look for, etc.

73,
Brian