Re: K3 Beta firmware rev. 2.82

Posted by Julian, G4ILO on Feb 14, 2009; 4:57pm
URL: http://elecraft.85.s1.nabble.com/K3-Beta-firmware-rev-2-80-Improvements-to-AFSK-A-DATA-A-SSB-AM-FM-DVR-tp2305650p2326853.html

Steven.Zabarnick wrote

I installed the new beta last and tested the new output power control. I
don't see any improvement in PSK31 output power using DATA A mode. I still
get nearly twice the output power than I have dialed in by the PWR knob. In
the previous firmware, the measure output power in CW modes agreed with the
PWR knob setting, but now the power output in CW is 20-30% higher than the
setting.

I will try to redo the transmitter gain calibration to see if this helps.

I have just got round to testing this firmware release. Before testing the power output in DATA A mode I did a power calibration.

It seems to me that there is still something wrong with the power control in DATA A mode. To make a comparison, I switched the input for SSB to LINE IN so I could compare the power output when sending a pure tone in both modes.

In DATA A the gain seems to have been reduced, and I had to increase the LINE IN setting. With PWR set to 50W and the input level set to give a steady 4 bars, I measured 80W on my power meter. A slight improvement but still not enough.

In SSB the power output was correctly controlled so that only 50W output was produced.

However, after switching between SSB and DATA a few times to compare the results, and also changing bands, I found that the output in DATA is not consistent. Currently I am getting about 65W for 50 selected. At one point on 20m I actually got 50W. On 30m I am actually getting 20W (yes, 20W) with 50W selected, absolutely no change to the audio input compared to the other bands, and 4 bars of ALC showing.

Back to the drawing board?