[Elecraft] K2 RF Gain control

[W3FPR - Don Wilhelm]

Bob,

If the RF gain control changes the number of LEDs on the S-meter reading, it 
is functioning properly.

Now, with that said, yes you MAY have the AGC Threshold set incorrectly.  As 
long as AGC action is present, the audio level should be more or less 
constant - that is its proper function.  When the AGC threshold is set too 
low (higher voltage on U2 pin 5, the K2 will produce more AGC voltage it 
should and will de-sensitize the receiver even with no signal.  The proper 
fine adjust setting for the AGC Threshold is just at the level where the K2 
internal noise does not activate the AGC - you can test that condition by 
switching from AGC on to AGC off on a quiet band or with no antenna 
connected.  If the noise rises with AGC off, the AGC Threshold is set too 
high.  I commonly find the correct setting will yield a voltage at U2 pin 5 
of 3.6 to 3.8 volts.

If you have a high noise level at your QTH, the noise alone may be 
activating the AGC and cause the conditions you describe.

73,
Don W3FPR

----- Original Message ----- 

>I have a K2 with almost all of the add-ons (everything but DSP - and the
> 100 watt amplifier has just been added) and all elecraft mods that has
> functioned well for over a year - but I recently noticed that the RF
> gain control doesn't change signal levels coming out of the speaker.
> The control has been left at max until I played with it recently, and I
> was surprised to notice that its only function seems to be changing the
> number of illuminated LEDs in the S-meter.  I tried it with various AF
> gain control levels and with the AGC both active and turned off - no
> difference.  Before I get into massive troubleshooting, is it possible
> over time and changing various internal settings several times I have
> misadjusted something?  I get signals on the bands.
>
> Bob Greenwalt
> K6VZT