[hpsdr] Munin problem
John
radio at mediacombb.net
Sun May 18 04:11:32 PDT 2014
I'm trying to get my Munin working with Alex and Hermes, now using
PowerHPSDR v 3.2.10 (4/10/14) and Windows 7 Pro 64 bit.
I did not notice any problem when running Munin without Alex into a
50 Ohm load using a signal generator for a signal source. The output
power was a little low on the higher bands and on some bands the bias
current readings were strange to me.
I calibrated my 30 dB power attenuator and cables for the ham bands
to 54 mHz using Hermes VNA and calculated the correct Voltmeter
readings to be used to set up the gain and Wattmeter settings in
PowerHPSDR. My Voltmeter is not fully calibrated, but it agrees
with each of my two signal generators. I used this setup to set the
gain in PowerHPSDR on all bands. At 12m I could not get 100W and the
supply current was lower than expected. The output was also low on
6m, but the supply current was very high. The PowerHPSDR wattmeter
was calibrated at 1.8 mHz using the same test setup.
However, when connected to an antenna having a low SWR and running
reduced power, PowerHPSDR indicated very high SWR and reflected power.
I then ran power from my TS-440 rig through Alex at 3.5mHZ (no PA,
Hermes on a dummy load with no drive and keyed in CW) and checked the
PowerHPSDR readings:
Forward Power 82 Watts
Reflected Power 1.0 Watts
SWR 1.3:1
This seems to indicated my problem(s) is not caused by Alex.
I also used an external SWR bridge and found very low SWR when using
a 50 Ohm load and very high SWR using an antenna.
The only explanation I can come up with is that my Hermes/Munin/Alex
system has very high spurious output and the antenna system is
reflecting the spurious output. I don't have access to a spectrum analyzer.
Is there another explanation for the above results?
73, John WoGN
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