All the AGC schemes for the uBitx I've seen thus far have audio derived detection of the signal level.
to create a control voltage, that control voltage is then used to attenuate the signal at some point prior to detection.
Measuring the control voltage tells us the signal strength.
Scaling that measurement to accurately show 6dB steps per S-unit across a large range
is generally more bother than it's worth.? Signal strength on any meter
will also be dependent on things like your antenna design and local geography.
S-meters usually aren't very accurate, even on commercial gear.
An accurately calibrated S-meter might be used as a tool for evaluating antennas.
But most of us just use S-meter readings when reporting the other guy's signal strength.
For that, you may as well just pick a number based on what it sounds like.
My advice:? Pick high, let the other guy feel good about his signal.
Jerry, KE7ER
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On Fri, Apr 2, 2021 at 02:27 AM, Vic WA4THR wrote:
You may have something there, Kobus. I wondered if the AGC operating back in the IF stages would limit things such that an S-meter reading audio level would always drop back to something lower, especially on strong signals. In my case I used an audio AGC that followed the high-side volume control tap and it and the S-meter read the same voltage such that the input voltage is not reduced by the AGC action. I bet that's it!
=Vic=
