To get to the “Prog” setting I gave previously for my 566, I disconnected the
antenna and shorted out the antenna connector. I then increased the AGC
threshold until the S meter read S9. This was 38.30 in my case. It is my
understanding from some papers I read earlier on the subject, the AGC would
then only act on signals above S9. My 566 certainly seems to operate in that
manner when I used my “Prog” setting.
Scott K4VWK
-----Original Message-----
>From: Robert Carroll <w2wg@comcast.net>
>Sent: Nov 10, 2011 10:17 AM
>To: 'Discussion of Ten-Tec Equipment' <tentec@contesting.com>
>Subject: Re: [TenTec] Orion gain setting
>
>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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