<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=iso-8859-1"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=DE-CH link=blue vlink=purple><div class=WordSection1><p class=MsoPlainText><span lang=EN-GB>***** High Performance Software Defined Radio Discussion List *****<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoPlainText><span lang=EN-GB>All,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB>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: <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>1<sup>st</sup>. 1 message (32 bits) bit 06 set bit 07 reset meaning transmitting to ANT2 what I intended.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>2<sup>nd</sup>. 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.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>3<sup>rd</sup>. 1 message (32 bit) bit 06 reset bit 07 set meaning transmitting to ANT1 which is causing high VSWR and may destroy the amplifier.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>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.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB>Thanks and 73<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB style='mso-fareast-language:DE-CH'>Hansjörg HB9BBP<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>