[Elecraft] An AGC Story

[Geoffrey Mackenzie-Kennedy]

Bob,

Yes I did see your post thanks, but have not yet had the opportunity to 
digest your results - but I will.

When you made these measurements, what settings did you use for the 'audio' 
Hi-cut and Lo-cut?

My thinking was that I would first look at the SA612's output wile injecting 
multiple signals, and then do the same at suitable points along the signal 
path as it made its way to the audio output. By doing this it should be 
possible to find the weakest link in the chain (in terms of IMD), and then 
attempt to do something to improve the 'weak link's' performance.

May I take this opportunity to stress that my comments were not intended to 
be any kind of criticism of the K3.

73,
Geoff
GM4ESD

 .
"Bob Henderson" <bob at 5b4agn.net> wrote on Sunday, December 12, 2010 4:11 AM:

<snip>

> I made within DSP b/w IMD measurements on my K3 and comparable
> measurements on my K2. These were included in a post dated 5 December
> but you may have missed it.
>
> The following measurements relate to K3 S/N 4904 on 7MHz with 2.7kHz
> roofing filter and 2.7kHz DSP b/w.  Default slow AGC was selected.
> The table shows input level at the K3 antenna connector for
> each of two carriers spaced 500Hz.  At each input level, the level of
> the strongest IMD product observed at the AF output using an HP8568B is 
> recorded
> alongside.

<snip>