[Elecraft] K3 RF Gain control reduced range after RF gaincalibration

[Al Lorona]

Fred, are you expecting the AGC OFF curves to always produce higher output than 
the ON curves? I'm not sure that's a correct assumption. I think the purpose of 
OFF is that you have control over the curve, that is, where you place the linear 
part of the dynamic range. It's like a variable attenuator in a spectrum 
analyzer.

There are two truths regarding AGC OFF:

As you reduce the RF Gain you should see a drop in audio output.

AGC ON is always going to give you a more compressed input-output 
characteristic, compared to AGC OFF. That's what AGC does; it wants to make 
signals equal to a greater or lesser extent depending on your AGC parameters.

It looks like your measurements have proven these two truths.

A sudden 10 dB jump at the 9 o'clock or any position is an issue. This brings 
up a good point... all those who have been experiencing 'pileup mush' should 
make sure that their RF calibration is correct. I bet you that's half of the 
problem.

Al  W6LX




________________________________
There does seem to be something strange in the way the RF gain works.
I also see the 10 dB change in audio level at the 9 o'clock position. 
In addition, the RF gain position seems to affect the way the AGC on and
off works as shown on 
http://www.ke7x.com/home/miscellaneous-k3-information/unexpected-agc-behavior