<head><style>body{font-size:10pt;font-family:arial,sans-serif;background-color:#ffffff;color:black;}p{margin:0px;}</style></head><body><font color="#000000"><font size="2"><font face="arial,sans-serif"><br></font></font></font><br>I believe there are existing solutions that should work. Rod I believe is going to retest using the inexpensive shielded cable he and I discovered.<br>Kjell believes the shielded cable should work well, the coax calculator indicates the impedance of this cable is actually closer to 25 ohm than the micro-dot product but I am not an expert by any means!<div>Tim<br>-----Original Message-----<br>>From: Bob Mahrenholz <bobm@edge.net><br>>Sent: May 23, 2012 11:17 AM<br>>To: la2ni@online.no, w4yn@arrl.net, rkolarik@neb.rr.com<br>>Cc: hpsdr@lists.openhpsdr.org<br>>Subject: [hpsdr] Ideas for Munin Picked up at Dayton Hamvention<br>><br>>***** High Performance Software Defined Radio Discussion List *****<br>><br>>Sent this out a few days ago and didn't get any comments. Thought <br>>maybe it did not go.<br>>Bob<br>><br>><br>>Hello Everyone,<br>><br>>I really enjoyed Dayton this year. After looking at all of the booths <br>>in the Exhibit Hall,<br>>I scoured the outdoor flea market looking for a small diameter <br>>co-axial cable to use in<br>>winding T1 for the output stage of Munin.<br>><br>>I found my answer at several of the places selling microwave <br>>components. It is RG-178,<br>>(Belden 83265). It has an outside diameter of only 0.71 inches (1.803 <br>>mm). The center<br>>conductor is 30 AWG, insulation is Teflon, and the shield is silver <br>>plated copper braid.<br>>Outer jacket is FEP. It's impedance is 50 ohms rather 25 but I do not <br>>think that this would<br>>be a problem with the short length involved. Mouser's price is <br>>$364.62 for a 100' spool.<br>>(See below)<br>><br>>It is a true co-axial cable rather than the "Control and <br>>Instrumentation Cable" that Belden<br>>83705 is. (Incidentally the 83705 is listed as "obsolete" in the <br>>Belden Catalog.)<br>><br>>The RG-178 may be found in Belden's Catalog:<br>><br>> https://edeskv2.belden.com/Products/#s=rg-178&r=0<br>><br>>Click on the cable number and then click on "Detail".<br>><br>>I purchased some 50' of the RG-178 at the Hamfest ($10 for a 25 foot <br>>roll). if someone<br>>would like to try out a piece. I don't know what length it would take <br>>for a single board<br>>but maybe some one of you knows.<br>><br>>At the TAPR presentation at Dayton by Steven Bible, N7HPR, the TAPR president,<br>>I learned that one of the functions of TAPR is to assist in the <br>>development of new<br>>boards. I propose that we get TAPR to purchase a 100 foot roll of <br>>Belden 83265 and<br>>then sell it in appropriate lengths to those of us putting together a <br>>Munin board.<br>><br>>73,<br>>Bob, K4QQK<br>><br>>p.s. Kjell, thanks for the info on the current measuring pins of J1.<br>><br>>_______________________________________________<br>>HPSDR Discussion List<br>>To post msg: hpsdr@openhpsdr.org<br>>Subscription help: http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org<br>>HPSDR web page: http://openhpsdr.org<br>>Archives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/<br></bobm@edge.net></div></body><pre>
Tim O'Rourke
W4YN@ARRL.Net
Low Power Amateur Radio Rocks
Member of Flying Pigs,ARCI,GQRP,RSGB,ARRL Life Member
NHRA Life Member</pre>
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