[hpsdr] problem with Alex

[HB9BBP]

***** High Performance Software Defined Radio Discussion List *****

 

All,

 

After using an Atlas based HPSDR for some years I stumbled over a problem
with Alex. I tried a piece of wire on ANT1 and a dummy load on ANT2.
Sometimes when trying to transmit into the dummy load I noticed a high VSWR.
My equipment PC with Win10 running PowerSDR V3.3.9, HPSDR: Atlas, Metis with
fw 3.0, Mercury-EU with fw 3.4, Penelope with fw 1.8, Alex and Excalibur.
Investigating the problem I found that when switching to transmit the
antenna relays K8 (ANT1) and K11 (ANT2) did not switch correctly about 1
time in 10. Monitoring the SPI bus to Alex showed 3 types of messages from
which all bits except bit 06 and 07 were always correct: 

1st.  1 message (32 bits)  bit 06 set bit 07 reset meaning transmitting to
ANT2 what I intended.

2nd. 2 messages (32 bit each). First message bit 06 reset bit 7 set meaning
transmitting to ANT1. Second message, following message 1 with delay up to
some ms, bit 6 set bit 7 reset meaning transmitting to ANT2. The first
message is absolutely not necessary.

3rd. 1 message (32 bit) bit  06 reset bit 07 set meaning transmitting to
ANT1 which is causing high VSWR and may destroy the amplifier.

The relays are switched as ordered by the messages. A friend of mine owning
a similar equipment except a TAPR build Mercury observed the same behaviour.
I repeated the test with Ozy and PowerSDR V2.2.14 with still the same
result. Has anybody observed the same? Help to solve the problem is
appreciated.

 

Thanks and 73

 

Hansjörg  HB9BBP

 

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