<div dir="ltr">Hi Lester,<br><div><br></div><div> Your comment is exactly the reason why I was puzzled that Bill was reporting LO leakage at 15 MHz - this seems strange to me.</div><div><br></div><div>73</div><div>Phil W1PJE</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jun 2, 2020 at 12:48 PM Lester Veenstra via TangerineSDR <<a href="mailto:tangerinesdr@lists.tapr.org">tangerinesdr@lists.tapr.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div lang="EN-US" style="zoom:0%"><div class="gmail-m_-3429418292219826106WordSection1"><p class="MsoNormal"><span style="font-size:22pt;font-family:Arial,sans-serif;color:rgb(31,73,125)">Have same 10 Mhz local contamination so just use 15 Mhz WWV<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:22pt;font-family:Arial,sans-serif;color:rgb(31,73,125)"><u></u> <u></u></span></p><div><p class="MsoNormal"><i><span style="font-size:11pt;font-family:"Copperplate Gothic Light",sans-serif;color:rgb(31,73,125)">Lester B Veenstra K1YCM MØYCM W8YCM 6Y6Y</span></i><i><span style="font-family:"Copperplate Gothic Light",sans-serif;color:rgb(31,73,125)"><u></u><u></u></span></i></p><p class="MsoNormal"><span style="font-size:10pt;font-family:Arial,sans-serif;color:rgb(31,73,125)"><a href="mailto:lester@veenstras.com" target="_blank">lester@veenstras.com</a><u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New";color:rgb(31,73,125)"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)">452 Stable Ln (HC84 RFD USPS Mail)<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)">Keyser WV 26726<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)">GPS: 39.336826 N 78.982287 W (Google)<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)">GPS: 39.33682 N 78.9823741 W (GPSDO)<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)">Telephones:<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)">Home: +1-304-289-6057<u></u><u></u></span></p><p class="MsoNormal" style="line-height:12.75pt"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)">US cell +1-</span><span lang="EN-GB" style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)">304-790-9192 <u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial Unicode MS",sans-serif;color:rgb(31,73,125)">Jamaica cell: +1-876-456-8898 </span><span style="color:rgb(31,73,125)"><u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"> </span><span lang="EN-GB" style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"><u></u><u></u></span></p></div><p class="MsoNormal"><span style="font-size:22pt;font-family:Arial,sans-serif;color:rgb(31,73,125)"><u></u> <u></u></span></p><div><div style="border-style:solid none none;border-top-width:1pt;border-top-color:rgb(181,196,223);padding:3pt 0in 0in"><p class="MsoNormal"><b><span style="font-size:10pt;font-family:Tahoma,sans-serif">From:</span></b><span style="font-size:10pt;font-family:Tahoma,sans-serif"> TangerineSDR [mailto:<a href="mailto:tangerinesdr-bounces@lists.tapr.org" target="_blank">tangerinesdr-bounces@lists.tapr.org</a>] <b>On Behalf Of </b>John Ackermann via TangerineSDR<br><b>Sent:</b> Tuesday, June 02, 2020 12:43 PM<br><b>To:</b> David McGaw; Engelke, Bill via TangerineSDR<br><b>Cc:</b> John Ackermann<br><b>Subject:</b> Re: [TangerineSDR] 10 Mhz leakage<u></u><u></u></span></p></div></div><p class="MsoNormal"><u></u> <u></u></p><div><p class="MsoNormal" style="margin-bottom:12pt">Yes, there'll be at least 10 MHz available for other uses.<u></u><u></u></p></div><div><p class="MsoNormal">73,<u></u><u></u></p></div><div><p class="MsoNormal">John<u></u><u></u></p></div><div><p class="MsoNormal">On Jun 2, 2020, at 12:26 PM, "David G. McGaw via TangerineSDR" <<a href="mailto:tangerinesdr@lists.tapr.org" target="_blank">tangerinesdr@lists.tapr.org</a>> wrote:<u></u><u></u></p><p class="MsoNormal" style="margin-bottom:12pt">On the other hand, while acknowledging the problem with receiving WWV specifically, I hope provision can be made to lock to 10 MHz and perhaps other frequencies. It is more likely that 10 MHz is available to lock various instruments together than 1 PPS in people's shack or lab. <br><br>Good coax is key for distribution. I have thrown out a lot of cheap RG-58 jumpers as they have poor shield coverage (sometimes as low as 35%). Genuine Belden or equivalent can be OK (95% coverage) though double-shielded (2 braids or braid + foil) is better. <br><br>73, <br><br>David N1HAC <u></u><u></u></p><div><p class="MsoNormal">On 6/2/20 11:47 AM, Phil Erickson via TangerineSDR wrote: <u></u><u></u></p></div><blockquote style="margin-top:5pt;margin-bottom:5pt"><div><p class="MsoNormal">Hi all, <u></u><u></u></p><div><p class="MsoNormal"><u></u> <u></u></p></div><div><p class="MsoNormal"> John has the right approach. <u></u><u></u></p></div><div><p class="MsoNormal"> <u></u><u></u></p></div><div><p class="MsoNormal"> Bill: I guess I don't understand how a 10 MHz clock can generate a 15 MHz harmonic, unless some kind of a divide-by-2 happens in the radio to get to 5 MHz and then you are seeing the 3rd harmonic. Others can add. <u></u><u></u></p></div><div><p class="MsoNormal"><u></u> <u></u></p></div><div><p class="MsoNormal">73 <u></u><u></u></p></div><div><p class="MsoNormal">Phil <u></u><u></u></p></div></div><p class="MsoNormal"><u></u> <u></u></p><div><div><p class="MsoNormal">On Tue, Jun 2, 2020 at 11:19 AM John Ackermann N8UR via TangerineSDR < <a href="mailto:tangerinesdr@lists.tapr.org" target="_blank">tangerinesdr@lists.tapr.org</a>> wrote: <u></u><u></u></p></div><blockquote style="border-style:none none none solid;border-left-width:1pt;border-left-color:rgb(204,204,204);padding:0in 0in 0in 6pt;margin-left:4.8pt;margin-right:0in"><p class="MsoNormal">10 MHz leakage is a real problem. cf my lab/ham shack. :-) <br><br>But I'm pleased to say that the current design for the Tangerine CKM <br>module will avoid, or at least won't add to, this problem. We're going <br>to directly slave the 122.88 MHz ADC/DAC clock to GPS PPS, with no 10 <br>MHz oscillator in the mix. So with good practices applied to the <br>digital layout, we shouldn't create any HF spurs in the clock system. <br><br>We will have a 10 MHz output available (synthesized in the FPGA) but it <br>will be for optional uses and we can make it switchable. <br><br>BTW, I don't recall for sure but on the original Hermes board which had <br>a 10 MHz TXCO to which the 122.88 MHz was locked, I don't think there <br>was any bleed-through noticeable in the receiver. So it's possible to <br>avoid the problem with good design. <br><br>The real problem is when the 10 MHz is running around on leaky coax <br>cables. Then it gets into the air and is pretty difficult to suppress. <br> (I found that cheap RG-58 jumper cables running in parallel in my lab <br>were porous enough to allow two OCXOs to injection lock -- I ended up <br>replacing all the jumpers with double-shielded cables and that problem <br>has gone away.) <br><br>73, <br>John <br>---- <br>On 6/2/20 11:04 AM, Engelke, Bill via TangerineSDR wrote: <br>> A little discovery that might have a bearing on something in the <br>> TangerineSDR…. Or maybe this is just my ignorance at work. <br>> <br>> <br>> <br>> We’re putting a lot of emphasis on being able to observe the doppler <br>> shift of WWV, often focusing on 10MHz. I have been looking at this using <br>> FlexRadio 6600 and Spectrum Lab. In observing the frequency moving <br>> around quite a bit (by this I mean 20 to 40 millihertz), I thought, <br>> maybe that is the Flex’s TXCO doing its thing. So I got a Leo Bodnar <br>> GPSDO and started using this as the Flex’s clock. <br>> <br>> <br>> <br>> What I noticed is that even with the antenna grounded and the rig <br>> connected to a dummy load, there is a pretty significant (and totally <br>> stable) 10 MHz signal shown in Spectrum Lab. I speculate that this is <br>> the clock signal finding its way into the front end of the receiver. So, <br>> when watching for WWV doppler shift, I see a 10 MHz signal (which is <br>> comparable in strength to WWV) superimposed on it. The same signal can <br>> be seen on 15 MHz and 20 MHz – not surprising, since the Leo Bodnar <br>> GPSDO provides a square wave output (i.e., rich in harmonics). I <br>> recognize that the Flex is not a lab instrument, so I have no grounds on <br>> which to complain, but still… <br>> <br>> <br>> <br>> I wonder if this will play into the Tangerine SDR? Are we able to keep <br>> RF from the clock from leaking into the front end and overlaying the WWV <br>> we’re trying to observe? Do we need to? <br>> <br>> <br>> <br>> Any thoughts? -73- Bill AB4EJ <br>> <br>> <br><br><br>-- <br>TangerineSDR mailing list <br><a href="mailto:TangerineSDR@lists.tapr.org" target="_blank">TangerineSDR@lists.tapr.org</a> <br><a href="https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fmailman%2Flistinfo%2Ftangerinesdr_lists.tapr.org&data=02%7C01%7CDavid.G.McGaw%40dartmouth.edu%7C02b7a4743765433aaddc08d8070c5441%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637267096824743913&sdata=aXd%2BtOj5Rs0tgfGXrWi1T402cGUqgXcbtof5Akn7hU0%3D&reserved=0" target="_blank">http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org</a> <u></u><u></u></p></blockquote></div><p class="MsoNormal"><br clear="all"><u></u><u></u></p><div><p class="MsoNormal"><u></u> <u></u></p></div><p class="MsoNormal">-- <u></u><u></u></p><div><p class="MsoNormal">---- <br>Phil Erickson <br><a href="mailto:phil.erickson@gmail.com" target="_blank">phil.erickson@gmail.com</a> <u></u><u></u></p></div><p class="MsoNormal"><br><br><u></u><u></u></p></blockquote><p class="MsoNormal"><u></u> <u></u></p><pre>-- <br>TangerineSDR mailing list<br><a href="mailto:TangerineSDR@lists.tapr.org" target="_blank">TangerineSDR@lists.tapr.org</a><br><a href="http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org" target="_blank">http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org</a><u></u><u></u></pre></div></div></div>-- <br>
TangerineSDR mailing list<br>
<a href="mailto:TangerineSDR@lists.tapr.org" target="_blank">TangerineSDR@lists.tapr.org</a><br>
<a href="http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org" rel="noreferrer" target="_blank">http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org</a><br>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature">----<br>Phil Erickson<br><a href="mailto:phil.erickson@gmail.com" target="_blank">phil.erickson@gmail.com</a><br></div>