PEP and forward power about double of set power

[Greg Buhyoff]

I own two K3s and the newest one (factory assembled) is showing a power output (both PEP and Forward) about double of what the power control indicates.

I have done an automated power calibration via the K3 Utility using a 1.1:1 50 ohm resistive dummy load connected to ant port 1 and used a power setting of "norm". The calibration routine indicated success at 5 and 50 watts.

 But, when I switch to SSB and transmit the power out is about double what I have my power control set at.  I have the tune control set for 10W and that  s what I get when I use the tune control for my Palstar Auto Tuner.

However, when I set the power to about 35 watts for my amp drive I am getting sometimes 70-75 watts out PEP and Forward Power is the same.   Trying various power levels on the K3 give similar results -- much higher than the setting.

 I have checked my power out numerous times using an LP-100A and Alpha 4510 which both give PEP and Forward power measurements.  I am using the Elecraft HM2 mic and tried  both low and high mic gain in the menu setting where you set the bias to on.  My mic gain is set for about 6-7 bars on the ALC scale and compression set for 1 lit bar on the scale.

I then did the auto power calibration again and all is well with a successful calibration indicated by the K3 power gain calibration routine.

I must be missing something, but for the life of me, I can't find it.  Or, I am having brain lock-up and not seeing the obvious.

Any help or suggestions would be most appreciated.

Thanks and 73,
Greg K2UM

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Julian, G4ILO]

Greg Buhyoff wrote

I own two K3s and the newest one (factory assembled) is showing a power
output (both PEP and Forward) about double of what the power control
indicates.

I have done an automated power calibration via the K3 Utility using a 1.1:1
50 ohm resistive dummy load connected to ant port 1 and used a power setting
of "norm". The calibration routine indicated success at 5 and 50 watts.

 But, when I switch to SSB and transmit the power out is about double what I
have my power control set at.  I have the tune control set for 10W and that
s what I get when I use the tune control for my Palstar Auto Tuner.

However, when I set the power to about 35 watts for my amp drive I am
getting sometimes 70-75 watts out PEP and Forward Power is the same.
Trying various power levels on the K3 give similar results -- much higher
than the setting.

 I have checked my power out numerous times using an LP-100A and Alpha 4510
which both give PEP and Forward power measurements.  I am using the Elecraft
HM2 mic and tried  both low and high mic gain in the menu setting where you
set the bias to on.  My mic gain is set for about 6-7 bars on the ALC scale
and compression set for 1 lit bar on the scale.

I then did the auto power calibration again and all is well with a
successful calibration indicated by the K3 power gain calibration routine.

I must be missing something, but for the life of me, I can't find it.  Or, I
am having brain lock-up and not seeing the obvious.

Any help or suggestions would be most appreciated.

Tell me about it! Though in my case, it happens only in DATA, not SSB.

You need to set the CONFIG menu entry TXG VCE to -3.0dB. That should fix it. Though why the K3 can't figure out the correct gain for itself is beyond me. Not everyone has an accurate power meter.