[Elecraft] S-Meter Sensitivity

[Ron D'Eau Claire]

> Have you tried turning the AGC off and on with no signal present?  On mine
I
> was getting a very noticeable decrease in background hiss with the AGC
> turned on and with no signals anywhere in the passband.
> Stephen
> W3SMK


I'm not sure just what this quest is all about, but if it helps, my K2 shows
a 1 dB increase in noise level when AGC is turned off and a 3 dB increase at
100 Hz bandwidth when AGC is turned off. That's the change in receiver noise
reported by Spectrogram with a dummy load connected to the antenna.  Preamp
and attenuator are off.

Some AGC systems used a "threshold", in which the AGC did not take any
action until the signal level coming through the receiver exceeded a certain
value. Clearly, the AGC in the K2 does not do this.


Ron AC7AC
K2 # 1289