Re: K3 S/N 222: Poor PSK31 IMD levels on 10m
Posted by
Dave, G4AON on
May 03, 2009; 7:43am
URL: http://elecraft.85.s1.nabble.com/Re-K3-S-N-222-Poor-PSK31-IMD-levels-on-10m-tp2773058p2776830.html
I was in contact with Julian yesterday and the problem seems to be
related to the computer sound card to line in/out cable. He's not sure
at this stage if it's rear panel grounding issues or not.
Measuring my K3's 2 tone IMD using the internal 2 tone generator, gives
3rd order products of -33 dB relative to one of the two tones (or -39 dB
as per the ARRL method of measurement) on 28 MHz at a power output level
of 30 Watts. Julian was using a power level of 20 ~ 30 Watts. The
figures are much worse when driving the low power PA hard at 10 Watts,
or the high power PA at 100 Watts.
73 Dave, G4AON
K3/100 #80
==================
>/ I was making only my second contact on 10m PSK31 this afternoon and
/>/ the station I was working gave me a very poor IMD report. I switched
/>/ on my KK7UQ IMD meter and sure enough the IMD was very poor, not quite
/>/ as bad as the station reported but showing values such as -15dB etc.
/>/ /
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