[Elecraft] K3 AGC Mush

[David Gilbert]

This has been a very real problem for serious contesters and is the 
number one dissatisfaction I have with the K3 ... and with Elecraft.

Multiple low level CW signals within a narrow passband simply turn to 
mush and are very difficult to distinguish.  I use the bare minimum AGC 
settings in an attempt to cope since turning AGC completely off during a 
contest can be painful to both the ears and the K3 itself (as those who 
have had to replace their audio ICs can attest) but that often does not 
adequately deal with the problem.  I have had little doubt that the 
culprit is some kind of low end nonlinearity and it is nice to know that 
your measurements tend to confirm that, but what I simply don't 
understand is why we have heard so little from Elecraft on this topic.  
On just about every other issue (even mind-blowingly trivial ones) 
Elecraft has responded quickly and effectively with both an explanation 
and a solution, but on this very important one we have heard virtually 
nothing and there seems to be no viable solution on the horizon.  I 
don't know if Elecraft doesn't believe the problem actually exists 
(possible, since I don't think any of the principle players consider 
themselves contesters first and foremost) or if they don't believe it is 
important or if they simply don't have a solution.  The silence has been 
deafening, though.

I personally know at least two top-tier contesters that are seriously 
considering replacing their K3s with a different rig because of this 
single issue, and I personally know two others who did not buy a K3 
because of it.  If I knew then what I know now I would not have bought 
my K3 either.  I spent a lot of money (tower, antennas, amplifiier) to 
be able to put a strong signal into various DX locations, and it is 
simply embarrassing to be working a pileup with a half dozen weak 
callers that obviously can hear me fine and not be able to pick their 
callsigns out of the mush.

No, it is not my ears and no, it is not my ability to copy CW.

Sorry for the rant, but I'm really really really tired of this 
fundamental problem being ignored.  We at least deserve some sort of 
explanation.

Dave   AB7E



On 12/4/2011 7:11 AM, Cady, Fred wrote:
> Neat site but unfortunately none of the audio clips demonstrate the
> pileups heard at dx locations like C6AAW. Once again this year the K3s
> AGC failed to perform adequately for us. I found many times I just had
> to turn AGC off. Signals were much cleaner and more distinguishable.
> I think there are two things going on. First, I think the threshold
> cannot be set high enough. The maximum is around S3 according to my
> measurements. Thus, when you have a pileup of signals all in the S3, S4,
> S5 region, which is common, AGC is compressing them together. When AGC
> is off, these signals are now in a linear region of the transfer curve
> and can be distinguished more easily. Second, and this is hard for me to
> judge since it has been a while since I've used an analog audio
> processing radio like the TS850, the audio doesn't sound "good". I
> dunno. I think there is an inherent harshness(?) to digitally produced
> audio as compared to analog audio. I'm not an audio guy, for sure.
>
> Sadly, I suspect top contesters are beginning to look for another radio
> to replace the K3 :-(
>
> 73,
> Fred
> KE7X/C6AKX/C6AAW
>