[Elecraft] P3TXMON VSWR Measurement Accuracy

[Wes (N7WS)]

I can't speak to the P3TXMON accuracy. I don't think it's specified anywhere, 
however, I don't own one and just skimmed the documentation.

That said, you should be worrying about your "calibrated" VSWR tester.  It's 
lying to you.  You would pay big bucks to get a precision termination guaranteed 
to 1.01 (46 dB return loss).

To have a power dummy load that good would be astounding.

On 9/8/2015 10:49 AM, Robert Nobis wrote:
> I am having a VSWR measurement accuracy issue with my P3TXMON.  I have a calibrated VSWR tester that indicates my antenna and feedline VSWR is 1.05:1. When I connect the P3TXMON and transmit, the PS display shows my VSWR is 2.0:1 into my feedline and antenna.
>
> I also tried testing into a dummy load. The VSWR tester shows a VSWR into the dummy load of 1.01:1, whereas the P3TXMON shows a VSWR of 1.29:1.
>
> Power level readings on the P3TXMON are within 5% of measured power levels using a power meter, so the P3TXMON is reasonably accurate measuring the transmitted power.
>
> In reviewing the P3 manual, I do not see any methodology for calibrating the VSWR measurement accuracy for the P3TXMON.
>
> Any suggestions on how to calibrate the P3TXMON for better measurement accuracy?
>
> Thanks and 73,
>
> Bob Nobis - N7RJN
> n7rjn at nobis.net
>
>