K3 Firmware Bug? Power Reduction After ATU TUNE

[Chuck - AE4CW]

I am seeing an approx. 20% reduction of peak SSB power after pressing ATU TUNE.  This occurs at both 50 and 100 watts into a high-quality dummy load as indicated on the K3 RF bar display and my external LP-100A wattmeter.  Bypassing the ATU does not restore the peak power, so I don't think it's caused by the ATU.  Pressing TUNE does restore full peak power until I press ATU TUNE again which causes the peak power to drop by approx. 20%.  I see this behavior in firmwares 2.02/1.77 and the beta 2.15/1.84.

I presume this is a firmware issue and will report to Elecraft but wanted to see if others are experiencing the same problem.

Chuck, AE4CW

[Dave, G4AON]

I've not specifically noticed that problem Chuck, but I do notice a
strange behaviour when running AF data modes...

If I start off relatively low in power, around 15 to 20 Watts, then try
to increase the power level it refuses to increase until I reach around
100 Watts then it only increases as I reduce the power level. By winding
up the power to 100W and back down to 50W I can obtain 50 Watts, but not
by turning the power up to 50W. It doesn't seem to be a slow time
constant issue.

Anyone else notice a similar effect?

73 Dave, G4AON
K3/100 #80 firmware 2.15/1.84 beta
-------------------------------------------------

I am seeing an approx. 20% reduction of peak SSB power after pressing ATU
TUNE. This occurs at both 50 and 100 watts into a high-quality dummy load
as indicated on the K3 RF bar display and my external LP-100A wattmeter.
Bypassing the ATU does not restore the peak power, so I don't think it's
caused by the ATU. Pressing TUNE does restore full peak power until I press
ATU TUNE again which causes the peak power to drop by approx. 20%. I see
this behavior in firmwares 2.02/1.77 and the beta 2.15/1.84.

I presume this is a firmware issue and will report to Elecraft but wanted to
see if others are experiencing the same problem.

Chuck, AE4CW
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[Max iw0gxy]

Chuck, I had a quite similar problem. My K3 was qrp waiting for the KPA3. When pushing tune I had full power (12W). Talking SSB I had full 12W but when I touched the power knob, even reducing 0.1W caused the power to drop to 8W peak. I had to retune to resume full power. I checked the LPA twice but at last I noted that it wasn't fully inserted. I pushed it firmly and now is working fine.
Ciao

Max IW0GXY  

Chuck - AE4CW wrote

I am seeing an approx. 20% reduction of peak SSB power after pressing ATU TUNE.  This occurs at both 50 and 100 watts into a high-quality dummy load as indicated on the K3 RF bar display and my external LP-100A wattmeter.  Bypassing the ATU does not restore the peak power, so I don't think it's caused by the ATU.  Pressing TUNE does restore full peak power until I press ATU TUNE again which causes the peak power to drop by approx. 20%.  I see this behavior in firmwares 2.02/1.77 and the beta 2.15/1.84.

I presume this is a firmware issue and will report to Elecraft but wanted to see if others are experiencing the same problem.

Chuck, AE4CW