[Elecraft] Mic Gain Changing

[Julian, G4ILO]

list1 wrote:
> 
> Hi Bob and All,
> I got home and did USB NCS duties tonite on MARS so I have a little more
> information.
> 
> It seems that when I first start transmitting even at a MIC gain of 25, I
> only initially get about 30 to 60 Watts of power out.  If the Mic gain is
> 15
> it is more like 35 Watts.
> 
> If I keep the Mic gain set at 25 and just start talking while starting the
> net the power out keeps increasing for about 30 seconds until it is at
> about
> 100 Watts.  The ALC is about 6 bars.  At this point I can turn the Mic
> gain
> down to 2 and still get 100 Watts out and have an ALC of 6 bars.
> 
> This is all done when the compression is set to 15 and is never changed.
> 
> If is funny but we had to go from the operating frequency at about 3.2 MHz
> to about 2.3 MHz tonite.  We did not have propagation at 2.3 MHz so we
> immediately went back to 3.2 MHz.  I had to press the tune button to put a
> signal out at 5 W to tune the manual tuner as I always do.  The Mic gain
> was
> still set to 25.  However when I started talking I was putting out only
> about 35 W, so I just kept talking and the power rose to about 100 W again
> in about 30 seconds.  Once again when I dropped the Mic gain down to 2, I
> still had 6 bars of ALC and 100 Watts out.
> 
> Thats why I said that the ALC thing with the K3 was not critical and
> seemed
> to be self adjusting.  Its just that I don't think my K3 #2080 is
> operating
> correctly.  By the way I still get raving reports.  I am heard with the K3
> much better than the TS480.  But I never used the processor with the TS480
> so its apples and oranges until I do more tests with the TS480.
> 
> 

This sounds like the same thing Dave G4AON has mentioned in earlier posts.

One thing worth pointing out is that it is not a good idea to tune at 5W or
50W. The K3 carries out a gain calibration when tuning is done at that exact
power level, but it assumes when doing this that the load is a perfect 50
ohms. If it isn't, the calibration could be incorrect. If you tune at 6W (or
even 5.1W) you should avoid this.

-----
Julian, G4ILO. K2 #392  K3 #222.
http://www.g4ilo.com/ G4ILO's Shack   http://www.ham-directory.com/ Ham
Directory    http://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 
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