Since we are on the AGC topic I'll ask a question. In days of yore when
tubes were king, there were several types of AGC, with only a few having an
AGC anywhere nearly as sophisticated as the Orion. The most common operated
by doing nothing until the RF signal exceeded a threshold. When the
threshold was exceeded, RF and maybe IF gain would be decreased. The audio
gain might be turned down as well.
I have an early 565, and there have certainly been many changes to the
details of how the AGC has worked as the various software loads have come
out. The manual which originally came with the 565 had a very vague AGC
description with some mention of RF and IF gain, but to me it indicated a
scheme very different from that of a 1950's tube set:
"The threshold value in the AGC system acts like an IF gain control for the
receiver chain--turn the value low (like to .37 uv) and the receiver gain
comes up, as do the signal levels."
I suppose it was the "up" which initially caught my attention. To me this
sounds a little like what used to be called "signal expander" operation.
Can anyone comment on whether this description is correct and how it relates
to the "compress a lot when the signal gets hot" operation of the SX28s
causing shelf sag in my basement?
73
Bob W2WG
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Rsoifer@aol.com
Sent: Thursday, November 10, 2011 9:25 AM
To: scotthsr@earthlink.net; tentec@contesting.com
Subject: Re: [TenTec] Orion gain setting
Right on Scott. Not only that, but this thread seems to be confusing the
565 and the 566. They're similar, but not identical as to settings.
73 Ray W2RS
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