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Re: f/w 2.73/1.98 power calibration

Posted by Steve Ward on Dec 15, 2008; 9:41am
URL: http://elecraft.85.s1.nabble.com/f-w-2-73-1-98-power-calibration-tp1651339p1657483.html

Richard Ferch wrote:

Steve Ward said:


> > I just applied the latest beta firmware as I have done many times
> > before, and it looks like this time my power calibration went out the
> > window.  I'm putting out about 70w on PSK31 when I dialed in 45.
> >
> > Just wanted to give folks a heads-up to watch their power output when
> > they start operating under new firmware, it might be time to re-calibrate!
>  

> It's more than just the power calibration. Even after calibrating power and
> setting the requested power below 50W, with either 2.73/1.98 or 2.72/1.98
> the power output on PSK31 (in DATA A) mode often exceeds the requested
> power, which results in splatter. I have been having to constantly ride the
> LINE IN and/or sound card output level controls in this weekend's PSK
> contest to keep the power below 50W and PSK signal quality acceptable; I
> have now switched back to 2.67/1.96 for the remainder of the contest.


Agreed that calibration is apparently not the issue.  I did some testing
with a dummy load.  Sending a PSK signal (just "TX" mode no data) I see
9 bars on the RF Power display on the K3.  The MFJ dummy load's meter
(FWIW) shows approx 50w average output but much higher peak reading.  I
have no idea how accurate the meter on the MFJ is, but something is
definitely changed with this revision.

73,
Steve
AD7OG
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