[600MRG] Inconclusive Pre-Sunset N1BUG JT9-2 Results

[k3mf]

Andy,    I had a 2200m JT9-2 QSO with Joe, WA9CGZ, completed with -30 on all decodes. We tried JT9-1 and I had no decodes. So it does seem to work with the longer period to find a signal. Once you reach -27...either mode will decode and the snr will be almost the same....at least that was my observation. 73,Wayde K3MF Sent from my Sprint Samsung Galaxy S9+.
-------- Original message --------From: N1BUG <paul at n1bug.com> Date: 12/12/18  5:31 PM  (GMT-05:00) To: Andy - KU4XR <ku4xr at yahoo.com>, RSGB LF Group <rsgb-lf-group+owner at groups.io>, 600 meter group <600mrg at mailman.qth.net> Subject: Re: [600MRG] Inconclusive Pre-Sunset N1BUG JT9-2 Results Thanks for the continuing reports Andy, and thanks to all otherparticipating stations.Actually your SNR reports make perfect sense. SNR is reported as thesignal level in a 2500 Hz bandwidth. This should not change betweenmodes. Therefore with the same SNR measuring algorithm in thedecoding software, SNR should be the same for both modes when bothcan decode the signal. What you are seeing appears to be just that,with perhaps a bit of QSB influence as expected.The slower mode should be able to decode 2 to 3 dB further into thenoise compared to the fast one. The theoretical limit for JT9-1 is27 dB. JT9-2 should be able to decode 2 to 3 dB less than that, so-29 to -30.I actuality, I believe the SNR calculation algorithm is not quitethe same between the two programs, so I would be cautions trying tocompare SNR directly. Some of the results I have seen tend to bearout my hunch that the respective relationship doesn't end up beingthe same on all receiving systems. This has probably led to muchconfusion as people try to compare the modes.I believe a better measure of one mode against the other is simplythis: is the slower mode able to decode the signal more often orunder more marginal conditions than the faster one. That is why I amrunning this test, in an effort to determine whether this is thecase. There is mounting evidence that JT9-2 is able to get themessage through more often than JT9-1.73,Paul N1BUGOn 12/12/18 4:53 PM, Andy - KU4XR via 600MRG wrote:> I started seeing traces of signal in the waterfall at 21:00 UTC - 7 minutes ater sunset at N1BUG, and 82 minutes> before Sunset at KU4XR.. The first decode of JT9-2 at 21:18 UTC is still an hour Pre-Sunset here.. Decodes of > both JT9-1, and JT9-2 have occurred consistently since.. Skywave component of course affecting Pre-Sunset> results.. Distance between stations is too far for daytime / groundwave reception.. > SNr reading is raising an eyebrow here, however I do not pretend to understand.. Both softwares receiving the> exact same audio feed, from the same radio.. I expected to see Higher Number SNr for JT9-2 compared to JT9-1> > 2118 -28  0.8 1350 2  VVV N1BUG 2>            > 2124 -26  0.8 1350 2  VVV N1BUG 2> 2126 -25  1.8 1350 @  VVV N1BUG 1> > 2130 -26  0.8 1350 2  VVV N1BUG 2                                                                  > 2132 -26  1.8 1350 @  VVV N1BUG 1 > > 73 all:> Andy - KU4XR______________________________________________________________600MRG mailing listHome: http://mailman.qth.net/mailman/listinfo/600mrgHelp: http://mailman.qth.net/mmfaq.htmPost: mailto:600MRG at mailman.qth.netMessage delivered to k3mf at aol.comThis list hosted by: https://www.qsl.netPlease help support this email list: https://www.qsl.net/donate.html
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