[Elecraft] [K3] Setting RF gain & AGC correctly

[Al Lorona]

Yes, I've heard about those amazing EME guys. I guess if you can copy signals below the noise you know who you are, and you can ignore guys like me!

I have been, of course, referring not to soundcard-decoded modes but to human ear-decoded modes, using a speaker or headphones. This is the scenario my calculations were based on.

I thank GM3SEK for clarifying that his post was an attempt at helping only the "pileup mush" guys, and point taken. The issue of setting your AGC correctly, however, applies in all situations.

Modern receivers have specs that differ by only a few dB. And yet, they sound radically different. Why? Could it be that, more than anything else, it's the AGC that makes or breaks them?

All the parameters that describe an AGC system conspire to give a receiver its characteristic "sound", and that sound ends up being something we like, something leading to listener's fatigue, or something in between.
These factors determine not only how a receiver deals with signals, but how it deals with noise. A well-behaved AGC can sound incredibly smooth. Poor (or misadjusted) AGC systems have probably caused many hams to sell otherwise good radios.

I have a few receivers here in the shack, and they all sound *totally different*. Some tire me out after a few minutes and I can listen to others all day and still enjoy what I hear.

Many modern receivers expose AGC parameters to the user and allow him or her a wide range of adjustment of those parameters. I'm starting to suspect that incorrect settings have caused many people to dismiss the K3 as "bad" or "noisy" or "fatiguing".

I happen to believe that the K3's AGC system is one of the best out there. But rather than force that opinion on anyone else, I usually encourage them to put the time into understanding and then setting their AGC parameters to try and capture that sound we all strive for. If you do this-- and use only as much gain as you need-- I really believe you'll enjoy your K3 more.


Al  W6LX