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<div data-externalstyle="false" dir="ltr" style="font-family: 'Calibri', 'Segoe UI', 'Meiryo', 'Microsoft YaHei UI', 'Microsoft JhengHei UI', 'Malgun Gothic', 'sans-serif';font-size:12pt;"><div>Some home made calibration standards:</div><div><br></div><div><a href="http://www.qsl.net/in3otd/electronics/VNA_calkit/SMA_female.html" target="_parent">http://www.qsl.net/in3otd/electronics/VNA_calkit/SMA_female.html</a></div><div><a href="http://www.qsl.net/in3otd/electronics/VNA_calkit/SMA_male.html" target="_parent">http://www.qsl.net/in3otd/electronics/VNA_calkit/SMA_male.html</a></div><div><a href="http://blog.kotarak.net/2010/04/n2pk-vna-sma-calibration-standard.html" target="_parent">http://blog.kotarak.net/2010/04/n2pk-vna-sma-calibration-standard.html</a></div><div><br></div><div>Roderick Wall, vk3yc.<br></div><div data-signatureblock="true"><br></div><div style="padding-top: 5px; border-top-color: rgb(229, 229, 229); border-top-width: 1px; border-top-style: solid;"><div><font face=" 'Calibri', 'Segoe UI', 'Meiryo', 'Microsoft YaHei UI', 'Microsoft JhengHei UI', 'Malgun Gothic', 'sans-serif'" style='line-height: 15pt; letter-spacing: 0.02em; font-family: "Calibri", "Segoe UI", "Meiryo", "Microsoft YaHei UI", "Microsoft JhengHei UI", "Malgun Gothic", "sans-serif"; font-size: 12pt;'><b>From:</b> <a href="mailto:nu8i@cox.net" target="_parent">Alfred Green</a><br><b>Sent:</b> Saturday, October 11, 2014 4:34 AM<br><b>To:</b> <a href="mailto:hpsdr@lists.openhpsdr.org" target="_parent">hpsdr@lists.openhpsdr.org</a></font></div></div><div><br></div><div dir=""><div id="readingPaneBodyContent">***** High Performance Software Defined Radio Discussion List *****<br><br>On 10/10/2014 6:49 AM, AA8K73 GMail wrote:<br>><br>><br>> What is a good 50 ohm termination to use for Hermes VNA calibration?<br>><br>> The open and shorted ones are easy. When I calibrate with a 50 ohm <br>> load and then measure other 50 ohm loads, I get variation.<br>><br>> I've tried a Decibel DB4303B, Relm T44100, Bird Termaline, and <br>> various, small BNC terminators.<br>><br>> Where can I find a 50 ohm precision terminator that will be flat on HF <br>> to 50 MHz?<br>><br>How accurate do you need? Finding a good load up to 50MHz is easy.<br>Using my HP8505 vna and HP8503 test set the worst of my collection of <br>loads was a 47ohm resistor in a BNC plug, and that gave >30dB return loss.<br>Most of the SMA and N loads were >38dB RL, with the best being near the <br>bridge limit of ~45dB, and the BNCs were >35dB. 'Waggling' the BNCs gave <br>a couple of dB variation, but they were still quite acceptable for such <br>a low frequency range.<br><br>I built a return-loss bridge for when I use my Hermes as a VNA, and it <br>was simple to get >30dB from 0.5 to 60MHz using one of my HP precision <br>loads as a reference. If you need better than that a different topology <br>is probably needed.<br><br>Finding a good load up through 10Gigs is more of a challenge!<br><br>GL & 73, Alf NU8I<br>Phoenix AZ DN33xo<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></div></div></div>
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