Wow, Don, the effect of setting the AGC THR is dramatic!

I live in a very rural location that seems relatively free of man-made
noise. With antenna connected, the K3 S-meter shows about S-5 background
noise. (S-0 with no antenna!)

Surprising to me, turning *down* the AGC THR to 002 (was set to 008) really
quieted things down and made signals "pop" out of the noise the way you
describe. (Note: NF and NB are OFF) I could hear the background noise level
rise monotonically as I increased the THR setting and fall as I decreased
it.

With seven AGC variables to adjust -- DCY, HLD, PLS, SLP, THR, -F and -S  --
setting AGC up for a given operating scenario in a given location seems like
a very complex topic. Is there any way this could be reduced to a tutorial
for the K3 Wiki (like K3NA's entry at
http://www.zerobeat.net/mediawiki/index.php/K3_Receiver_Gain_Configurations,
which addresses the "no AGC" case)?

This might create a run on N-GENs...

-- 
73 -- Brian -- K1LI

On Tue, Feb 2, 2010 at 4:50 PM, Don Wilhelm <w3...@embarqmail.com> wrote:

> I just thought of something that might help those confused by the AGC
> Threshold setting. One other way to look at the required AGC Threshold level
> is to think of it as an S-meter level If your noise is S-1 or lower (on the
> K3's S-meter), you can set the Threshold to 002 or higher and all may be
> well OTOH, if you have an S-7 noise level indicated, the AGC Threshold
> should be set to 008 or higher.
>
> This is not an exact science number - the AGC Threshold menu parameter
> values are not tied to the S-meter, but hopefully the relative scale can
> give you an indication of which way to move the setting to avoid activating
> the AGC on the ambient noise coming in on your feedline.
>
> As I have said before I believe the default setting of 005 is even too low
> - mine normally is set at 008 even though I have a relatively quiet
> location.
>
> 73,
> Don W3FPR
>
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