Jerry,
Thanks for the reply. In previous correspondence with Gary Barbour at
TenTec, he did tell me that the SMeter reading is actually a combination of
both the analog RF and digital signal levels.
My problem wasn't receiving interference from a strong off-channel signal
(although I do notice that from time to time - when the old TenTec 20m net
was 5 kHz above the Collins net, a couple of stations on the Collins net
caused a crackling noise when I was listening to the TenTec net). I suspect
that in addition to being strong signals, they were also a tad wide.
The SMeter was following the audio of the on-channel signal. The 75m
incident I mentioned was with two stations in QSO on the same frequency. The
SMeter acted up for the stronger one, but not for the weaker one (although
the weaker one was still 10 db over S9 - because of the SMeter acting up,
I'm not really sure of the strength of the stronger one - it was as least 20
to 30 db over )
Mark
----- Original Message -----
From: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
To: "Mark Erbaugh" <mark@microenh.com>
Cc: <tentec@contesting.com>
Sent: Tuesday, January 28, 2003 22:35 PM
Subject: Re: [TenTec] Pegasus S-Meter Anomaly
> It may be that there are two AVC loops. I'd expect one working at RF to
> protect the A/D from being overdriven, and a second one working after
> detection and filtering to level the audio for the speaker. It may be
> that the simple AVC reading option reads only the RF AVC. If so, that
> could show a strong signal indication while receiving a weak signal
> adjacent to a strong signal, when the strong signal was still in the A/D
> input passband. But the combination of the strong RF AVC and weak audio
> AVC ideally should be indicated as a weak signal.
>
> 73, Jerry, K0CQ
>
> --
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
> Reproduction by permission only.
>
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