Ok, thanks to the dozen who have responded.
Results:
Leave AGC on Fast all the time: 8 out of 12
Always leave AGC OFF, use "old" way: 3
No response to AGC question: 1
Do use RF gain to adjust signal level: 9 of 12
Leave RF gain on full all the time: 1, no comment about AGC
Most interesting input, for me, was a quote from a Collins
Radio S-line manual, not sure if each of you saw it, so here
is the quote:
"To copy CW with AGC, set R.F.GAIN to maximum and
adjust A.F.GAIN for desired level. If AGC action is not
desired, reduce R.F.GAIN setting until S-meter does not
kick with signals, and leave A.F.GAIN set as above. This
method of operating results in optimum signal- to- noise
ratio as well as more pleasing sidetone level. The practice
of operating with A.F.GAIN at maximum and adjusting
R.F.GAIN will degrade signal- to- noise performance of the
receiver."
Note: I do not know if the above is the exact text from the
Collins manual; and, I changed "avc" which was in the text
I rcv'd to AGC, just for consistency in our discussion.
Now, I find the above Collins bit to be unclear!! In the
second sentence, they do not say to turn OFF the AGC,
just to turn down the RF gain until the S-meter does not
"kick". Does that "defeat" the Collins AGC action? And,
"leave AF Gain set as above", does that mean set to
comfotable listening level, or set someplace in particular,
such as exactly where it was when the AGC was on, and
the RF GAIN was at full on?
Whatever is meant, Collins engineers seem to say this
arrainges things for "optimum" signal to noise, and
most pleasing sidetone level (sound volume, I guess).
Really does seem to be saying to leave the audio gain
right where it was set when the AGC was on, and the
RF gain was full up.
Anybody able to offer clarification on how the S-line
actually was used by those in the know back then??
Thanks again, and 73, Jim, KH7M
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