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<div class="">Hi Glen,</div>
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<div class="">Not sure if your referring to a issue with software of hardware….</div>
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<div class="">Is the issue you have on the original Alex or only on your new design?</div>
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<div class="">Have you tested your board with a dedicated bus driver so you can activate each relay on the board? </div>
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<div class="">Are,you testing with one of the SDR packages using setup?</div>
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<div class="">Did you see the following note in Appendix A:</div>
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<div style="margin: 0px; font-size: 9.5px;" class="">Note 1.) The RX 1 OUT switch also controls the default input</div>
<div style="margin: 0px; font-size: 9.5px;" class="">path for the normal receive function (that is, receiving from</div>
<div style="margin: 0px; font-size: 9.5px;" class="">the same antenna port as you are transmitting on.) In the event</div>
<div style="margin: 0px; font-size: 9.5px;" class="">that it is desired to receive through XV IN, RX 2 IN, or RX 1 IN,</div>
<div style="margin: 0px; font-size: 9.5px;" class="">then RX 1 OUT should be turned ON, so as to disconnect the</div>
<div style="margin: 0px; font-size: 9.5px;" class="">normal (default) receive path from the transmit antenna port.</div>
<div style="margin: 0px; font-size: 9.5px;" class="">If an external filter is to be placed in the normal receive</div>
<div style="margin: 0px; font-size: 9.5px;" class="">path, then both RX 1 OUT and RX 1 IN should be turned on,</div>
<div style="margin: 0px; font-size: 9.5px;" class="">and the filter connected between the RX 1 OUT and RX 1 IN</div>
<div style="margin: 0px; font-size: 9.5px;" class="">BNC connectors.</div>
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<div style="margin: 0px;" class="">Is U3 bit 0 pin at 12V?</div>
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<div style="margin: 0px;" class="">Since relay driver is open drain you should be able to activate the relay by grounding the U3 bit 0 output. If you have inadvertently connected 12V to this pin you will pull down your supply. You could use a small series resistor
for this test.</div>
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<div style="margin: 0px;" class="">The Alex schematics posted look correct.</div>
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<div style="margin: 0px;" class="">Hope this helps you.</div>
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<div style="margin: 0px;" class="">Bob, N5BRG</div>
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<blockquote type="cite" class="">
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<br class="">
Message: 2<br class="">
Date: Sun, 7 Jun 2015 10:11:18 -0400<br class="">
From: "MDS Info" <<a href="mailto:info@mds-ham.com" class="">info@mds-ham.com</a>><br class="">
To: "HPSDR" <<a href="mailto:hpsdr@lists.openhpsdr.org" class="">hpsdr@lists.openhpsdr.org</a>><br class="">
Subject: [hpsdr] Alex board<br class="">
Message-ID: <<a href="mailto:OLEMLLLENPOJJLABJGKJGENDLCAA.info@mds-ham.com" class="">OLEMLLLENPOJJLABJGKJGENDLCAA.info@mds-ham.com</a>><br class="">
Content-Type: text/plain;<span class="Apple-tab-span" style="white-space:pre"> </span>
charset="iso-8859-1"<br class="">
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Hello,<br class="">
<br class="">
I have designed and built an Alex clone with all the Alex features on a<br class="">
single board to match<br class="">
the size of the Hermes.<br class="">
<br class="">
On my checkout of the board, I noticed that XVTR RX relay is not activating.<br class="">
Bit 0 of U3 is high and never<br class="">
goes low. All the other relays work.<br class="">
<br class="">
Is this a known problem?<br class="">
<br class="">
All the HP, LP, antenna relays are functioning.<br class="">
<br class="">
???<br class="">
<br class="">
73's<br class="">
<br class="">
Glen K4KV<br class="">
<br class="">
<br class="">
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</blockquote>
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