[Elecraft] K3: AGC THR doesn't go low enough

[W5UXH]

For me, it is more than a perception.  To demonstrate this to myself, I used
the XG-2 set at 50 uV (so a good strong S9 signal) and for my normal
operating setup I see a tone (from the XG-2) in the presence of very
noticeable noise on an oscilloscope when looking at the K3 audio output.

I believe I understand why this happens in my case.  I believe it is because
as a 100% CW  100% QSK type, I am not able to operate with the RF gain at
maximum.  If I do this, then when I am talking, the band noise is greatly
amplified in between elements by the AGC, in the absence of other received
signals.

For this reason I have spent the last 50 years using the RF gain as my
primary level control, keeping it as low as possible for the band conditions
and signal I am in QSO with.

With the K3, the received signal sounds great with RF gain at max.  But it
is not possible to think when transmitting with the RF gain at max, due to
band noise.

With the RF gain turned down to an appropriate level for decent QSK (and the
AF gain subsequently set higher), the "perceived" extra noise is very real
as seen on the scope, and typically, in the absence of signals, there is no
change in the noise when I ground the antenna.  Of course with RF gain at
max there is a big change in noise when I ground the antenna.

So, I really doubt there is any "cure" for me.  I have played with the AGC
SLP and THR parameters per suggestions in the main thread under this subject
just in case.  But I suspect clean QSK and RF gain at max are just mutually
exclusive with the K3.  If anyone can point me to a setup where this is not
the case, I would be happy to investigate.

This is not the case with my FT-1000MP.  I have no idea what the reason for
this difference is.  Unfortunately the MP keying waveform leaves a bit to be
desired.  Maybe I will finally be forced to try one of the key click mods!

Chuck, W5UXH
Las Cruces, NM


P.B. Christensen wrote:
> 
>>I had resigned myself to living with the AGC off because I can't stand
>>the sound of the audio with it on in CW mode..
> 
> I have similar perceptions in CW mode and generally leave AGC turned off. 
> 
> 

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