Bob,
How are you testing?
If you are testing with the P3TXMON and your 'calibrated VSWR tester' in
series with your feedline, then those numbers may be incorrect.
The 'calibrated VSWR tester' is reading the SWR seen looking into your
antenna, but the P3TXMON is looking at the SWR looking into the input of
your VSWR tester - and that may be two different things.
If you want to do a valid test, obtain the SWR reading on your VSWR
tester, and then take the feedline off that tester and connect it to the
P3TXMON directional coupler and compare the SWR reading obtained from
that combination.
In other words, while your VSWR tester may be calibrated at its output,
there is no guarantee that its coupler does not introduce an SWR at its
input. Switching the same coax from the output of your tester to the
output of the P3TXMON is the only valid test.
73,
Don W3FPR
On 9/8/2015 1:49 PM, 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?
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
