<html><head></head><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:16px"><div id="yui_3_16_0_ym19_1_1473007820587_7565"><span id="yui_3_16_0_ym19_1_1473007820587_7566">Brad - </span></div><div id="yui_3_16_0_ym19_1_1473007820587_7565"><span><br></span></div><div id="yui_3_16_0_ym19_1_1473007820587_7565" dir="ltr"><span id="yui_3_16_0_ym19_1_1473007820587_7576">That's the symptom: dual decodes, one is the carrier and the other is one of the sidebands. If you're using WSJT-X and have the waterfall display on, you can clearly see both sidebands at the bottom of the panel. In your case it appears that the sideband is only 5dB down from the carrier; but the way WSJT-X arrives at the S/N is a bit mysterious. A spectrum analyzer or using Sprectravue with an SDR would be a better measure of the sidebands. Note that the sideband and carrier are exactly 120 Hz apart.</span></div><div id="yui_3_16_0_ym19_1_1473007820587_7565" dir="ltr"><span><br></span></div><div id="yui_3_16_0_ym19_1_1473007820587_7565" dir="ltr">I'm using my RPi attached to the back of the "official" touchscreen display and am wondering whether a 120 Hz scan signal is modulating the carrier. Is you RPi in a separate box, away from the monitor?</div><div id="yui_3_16_0_ym19_1_1473007820587_7565" dir="ltr"><br></div><div id="yui_3_16_0_ym19_1_1473007820587_7565" dir="ltr">Ron, W6XY</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1473007820587_7564"><br><br></div><div class="yahoo_quoted" id="yui_3_16_0_ym19_1_1473007820587_7553" style="display: block;"> <div style="font-family: times new roman, new york, times, serif; font-size: 16px;" id="yui_3_16_0_ym19_1_1473007820587_7552"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;" id="yui_3_16_0_ym19_1_1473007820587_7551"> <div dir="ltr" id="yui_3_16_0_ym19_1_1473007820587_7550"> <font size="2" face="Arial" id="yui_3_16_0_ym19_1_1473007820587_7556"> <hr size="1" id="yui_3_16_0_ym19_1_1473007820587_7563"> <b id="yui_3_16_0_ym19_1_1473007820587_7555"><span style="font-weight:bold;" id="yui_3_16_0_ym19_1_1473007820587_7554">From:</span></b> Brad Farr <taprsig@unsupported.org><br> <b><span style="font-weight: bold;">To:</span></b> TAPR HF Modes SIG Mailing List <hfsig@tapr.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Sunday, September 4, 2016 7:06 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [hfsig] Sidebands on Raspberry Pi WSPR carrier<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_ym19_1_1473007820587_7684"><br><div id="yiv3739227544"><div id="yui_3_16_0_ym19_1_1473007820587_7683"><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;" id="yui_3_16_0_ym19_1_1473007820587_7724">I'm new at this, but I observed the same thing in my initial testing, and was about to ask the same question.</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;min-height:14px;" id="yui_3_16_0_ym19_1_1473007820587_7710"><br></div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;" id="yui_3_16_0_ym19_1_1473007820587_7723">An example:</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;min-height:14px;" id="yui_3_16_0_ym19_1_1473007820587_7682"><br></div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;" id="yui_3_16_0_ym19_1_1473007820587_7694">From the raspberry pi -</div><div id="yui_3_16_0_ym19_1_1473007820587_7711"><br></div><div id="yui_3_16_0_ym19_1_1473007820587_7713"><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Times;" id="yui_3_16_0_ym19_1_1473007820587_7712">Desired center frequency for WSPR transmission: 14.097166 MHz</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Times;" id="yui_3_16_0_ym19_1_1473007820587_7714"> Waiting for next WSPR transmission window...</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Times;" id="yui_3_16_0_ym19_1_1473007820587_7715"> Obtained new ppm value: 1.16522</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Times;"> TX started at: UTC 09-04-2016 13:38:01.002</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Times;" id="yui_3_16_0_ym19_1_1473007820587_7716"> TX ended at: UTC 09-04-2016 13:39:51.679 (110.678 s)</div></div><div id="yui_3_16_0_ym19_1_1473007820587_7717"><br></div><div id="yui_3_16_0_ym19_1_1473007820587_7686"><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;" id="yui_3_16_0_ym19_1_1473007820587_7685">And what I decoded -</div></div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;" id="yui_3_16_0_ym19_1_1473007820587_7718"><br></div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;" id="yui_3_16_0_ym19_1_1473007820587_7720"><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Times;" id="yui_3_16_0_ym19_1_1473007820587_7719">1338 -26 -0.9 14.097006 -1 KW1BF DN41 10</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Times;" id="yui_3_16_0_ym19_1_1473007820587_7721">1338 -21 -0.9 14.097126 -1 KW1BF DN41 10</div><div id="yui_3_16_0_ym19_1_1473007820587_7722"><br></div><div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;">Some details -</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;">Raspberry Pi 2, the TAPR wspr board is connected via coax to an OCF dipole (an MFJ-2012), but I observed the same thing with a piece of random wire.</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;">For receiving I used a Sony ICF-2010, in the same room as the raspberry pi, with no external antenna, and with the built in telescoping antenna fully retracted and folded. The local/DX attenuator switch set to local, and RF gain slider at about midpoint. Dial frequency 14095.6 kHz, USB mode. Using WSPR-X on a Mac.</div></div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;"><br></div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;">If there are other things I should try or observations I should report, please let me know.</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;"><br></div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;">Thanks,</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;">Brad</div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 12px/normal Helvetica;"><br></div></div><div><br></div></div></div><br>_______________________________________________<br>hfsig mailing list<br><a ymailto="mailto:hfsig@tapr.org" href="mailto:hfsig@tapr.org">hfsig@tapr.org</a><br><a href="http://www.tapr.org/mailman/listinfo/hfsig" target="_blank">http://www.tapr.org/mailman/listinfo/hfsig</a><br><br><br></div> </div> </div> </div></div></body></html>