[R-390] Lankford AGC Mod ?

[Kurt]

Roger
Check with Barry Hauser here on the list for back issues of the Hollow state
News letter, he is now the editor. There are four maybe five issues that
cover the Langford mod in its various iterations. If Barry can't help you
let me know and I will copy them and mail the info to you.
Kurt Holbrook
----- Original Message -----
From: "Roger L Ruszkowski" <rlruszkowski@west.raytheon.com>
To: <r-390@mailman.qth.net>
Sent: Friday, January 11, 2002 9:37 AM
Subject: [R-390] Lankford AGC Mod ?


>
> I understand the Lankford AGC mod to be two diodes in the AGC
> circuit and a cap change to allow more BFO insertion into the
> detector.
>
> I understand what happens when we inject more BFO
> into the mixer (detector) circuit.
>
> I do not understand how the diode mod causes the
> difference we do hear in single side bans signals.
>
> How does that circuit work?
> What is the difference in AGC action of the circuit?
> Why does SSB sound better with the change?
> What caps should we experiment with to give better time constances?
> What would be some target values for those caps?
>
> Other than exceeding the PIV or forward current load of
> the diodes does the choice of diode make a difference?
>
> Is diode linearity critical for this circuit?
>
> Is diode switching time critical for this circuit?
>
> I know this is all available some where.
> Does some one have it handy and can you
> send me some clues.
>
> Thanks
>
> Roger KC6TRU
>
>
>
>
>
>
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