[Elecraft] K2 # 2448 queries

[Bill Coleman]

On 4/2/02 4:50 PM, Ron D' Eau Claire at rondec@easystreet.com wrote:

>For SSB or AM phone, you want it to react fairly quickly so
>that it will turn down the gain quickly when a strong signal appears, and
>then it will quickly bring up the gain of the receiver if the signal fades.
>For that use, the "FAST" setting is usually best.

I generally prefer the "SLOW" setting for SSB, although I sometimes use 
the "FAST" setting when listening to weaker signals in the vicinity of 
strong QRM. (My TS-430S only uses a slow AGC setting on SSB)

>So, for CW, a "Slow" setting is provided that will cause the AGC
>to wait a brief period before it brings the gain up at the end of each dot
>or dash. That will prevent the "pumping" effect on most signals, while still
>allowing the AGC to follow slower changes in the signal levels due to QSB.

For really strong CW signals, I prefer a "SLOW" setting, because the AGC 
attack produces a harsh click-like sound at the leading edge of the CW 
elements. For other CW work, "FAST" works pretty well, especially on weak 
signals. (My TS_430S only uses a fast AGC setting on CW)

>If your read the older texts for proper receiver operation back when CW was
>the dominant mode in Ham communications, you will see that nearly everyone
>ran the audio gain up pretty high - set just below the level where the audio
>amplifier's background noise became noticeable - and used only the r-f gain
>control to adjust the volume.

That's because those old-time radios didn't have an AGC at all, and those 
that did had one that was only suitable for AM receiption -- not for CW 
or SSB!

Don't forget that the preamp and attentuator can be used to make signals 
more palatable to the AGC as well! 

But I'll agree that the RF gain is the most underused control.



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