Hi Iztok, greeting from JA.
It passed about a half year after hearing your noise about “diversity reception” proposal and I am glad you changed the noise to the real signal today. Unfortunately, I am under the transition from six year old dual core to six core Desktop PC and I could not use JTSDK under Windows. Thus, Yesterday, I recompiled your source under Linux and checked “time diversity” proposal along with QUISK and single receiver RedPitaya configuration. Yes, you were correct and we missed “time diversity” technology at that time discussion and your demonstration is enough to convince me to pursue it as the first choice in our application rather than your described “overcomplicating protocols” technologies. As you indicated, we have been naturally using selective “time diversity” technique i.e. one out of repeated messages under QRM and QRN. If we combined them we have another few dB gain for everyone without any additional hardware. I hope you will soon implement them into future release soon. Regards, take De JA5AEA P.S: I am happy if you hear my noise about your baby project when it comes to my mind with separate communication. Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10 From: Iztok Saje <iztok.s...@telekom.si> Sent: Friday, February 1, 2019 2:45:49 PM To: wsjt-devel@lists.sourceforge.net Subject: [wsjt-devel] FT8 diversity patch Hello! Following some discussion on this forum, where I was too noisy, make me think. When joining two uncorrelated FT8 frames (taken on exactly same frequency, but not at the same time) main problem is how to synchronize all tones? My solution is to shift frames 7 times and do decoding after each shift, thus every tone get summed up in phase (or close enough). CPU load is few times higher as with standard decoder, but my I7 CPU can do it on time. Testing in 1.9.1 gave me excellent results: I made several QSOs where plain FT8 decoder would fail. Source code for WSJTX 2.0.0 with more detailed description is now tested a bit and available at http://lea.hamradio.si/~s52d/ft8div page. You have to compile it yourself. Time diversity (also called incremental redundancy) works by combining two consecutive even/odd frames, good to take repeated messages out of the QRM/QRN. Space diversity (called stereo diversity by W8JI) works when twp copies of WSJTX are run with phase synchronuos RX like K3, IC-7610 etc. Bursts from two RX/antennas are combined. Data is exchanged using temporary files, so both WSJTX copies need separate configuration file. IMHO this approach is worth to be considered to be included in one of the future releases. Best 73, mni DX, CU Iztok, S52D [http://psn.sdn.si/ts/podpis-neo-4.jpg] <https://www.neo.io/> Pravni pogoji / Legal disclaimer Telekom Slovenije, d.d., Ljubljana <http://www.telekom.si/disclaimer> _______________________________________________ wsjt-devel mailing list wsjt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wsjt-devel
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