Rob, The fst4w_calls.txt file is not used to resolve the hash in type 3 FST4W messages. It is used to validate decodes obtained when jt9 is called with the “-d 3” option, which enables a decoding pass that treats the FST4W message’s CRC bits as if they were parity bits rather than message bits. This trick decreases the size of the space that we have to search for codewords by many orders-of-magnitude in trade for giving up the ability to discriminate against false decodes that is normally provided by the CRC. The fst4w_calls.txt file provides a memory of calls that have previously been decoded using the standard CRC-protected decoding method. This memory is used to reject false decodes whenever we use the CRCless decoding approach.
Note that the fst4w_calls.txt file is written to disk only when jt9 is called with the “-d 3” option. The hash table that is used for resolving callsigns in the “type 3” messages is maintained internally in jt9 and is not written to disk. Steve k9an > On Jun 12, 2022, at 8:41 PM, Rob Robinett via wsjt-devel > <wsjt-devel@lists.sourceforge.net> wrote: > > Hi, > > In version 3.0 of my wsprdaemon software for Linux systems > (http://wsprdaemon.org/ <http://wsprdaemon.org/>) I am decoding FST4W by > running 'jt9 --fst4w ...' > jt9 outputs spot lines for type 1 spots, but for a type 3 spot which follows > it in the next WSPR cycle jt9 always outputs the callsign '<...>' > I can see that the file 'fst4w_calls.txt' is created when WSJT-x decodes > those same spots, and I suspect that file is used to look up the hashed calls > in a type 3 packet, but that file is never created when I run jt9 standalone > on Linux. > The format of fst4w_calls.txt is simple and my code could create it for jt9, > but inspecting "fst4_decode.f90" with my limited familiarity with Fortan > suggests that jt9 will maintain that file in the same way "wprd" does its > hash table file. > > So how can I get jt9 to resolve the hashed calls in type 3 FWT4W spots? > > I now have 30 receive sites worldwide listening for FST4W spots 24/7/365, and > solving this hashed calls problem will complete their ability to report all > FST4W transmissions. > > Thanks, > > Rob > > > -- > Rob Robinett > AI6VN > r...@robinett.us <mailto:r...@robinett.us> > mobile: +1 650 218 8896 > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel
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