[Icom] 751 AM problem

Tue, 05 Feb 2002 12:23:43 -0800

Hi Chris,

You may have the resting carrier output set too high. The RF Power control
should be set to 20W (no more than 25W) carrier output with zero modulation.

If you have access to an oscilloscope, you can take a look at the RF
envelope. The peak-to-peak amplitude at 100% modulation should be twice that
displayed with zero modulation. If you observe flat-topping on voice peaks,
you will need to turn down the Mic gain control.

AM on all the filter-type transceivers is a compromise. The newer DSP rigs
(IC-756 onwards) "do it right", by generating a mathematically-perfect
double-sideband AM signal in the DSP.

Best 73,
Adam, VA7OJ/AB4OJ
North Vancouver, BC, Canada
http://www.qsl.net/ab4oj/
Note new e-mail address:
mailto:[email protected]

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of NI4L
Sent: Tuesday, February 05, 2002 12:11
To: [email protected]
Subject: [Icom] 751 AM problem

Hi
i have a 751  it has the am filter installed. When i use am it swings
backwards.
doesn't work good at all on AM.
Sometimes i can can key it up and it swing forward then the next time i
key it up and talk into it it swings backwards.
Anybody have any suggestions?
thanks
chris NI4L

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