[Elecraft] K2 AGC

[Bill Coleman]

On 4/3/03 8:07 PM, k6se@juno.com at k6se@juno.com wrote:

>A question for the experts on the K2:
>
>The S-meter on my K2 (#2622) has always been very stingy.  Long ago I was
>told by Gary Surrency of Elecraft that if I reduced R1 on the control
>board to 33k, it would increase the S-meter sensitivity.  I left it
>unchanged until today (although I did change the diode he mentioned to a
>more "sensitive" one, which helped the S-meter slightly).

I had a problem with the AGC that eventually turned out that Q12 was bad. 
I replaced it with a 2n2222A that I had in the junkbox.

I had R1 at 33 K at Gary's suggestion, largely because of the stinginess 
and the earlier trouble I had. After the A->B mods I tried a pot at R1. I 
never could make the background change when AGC switched off entirely go 
away, but 30 K was the point it was the most subtle.

My R1 is 30.1K, and a carefully selected diode with maximum Vf. I think 
my AGC action is near perfect, not nearly as stingy as earlier.


Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901