What I don't understand is why NOBODY uses the pskmail arq chat mode, which adds an ARQ layer to modes like PSK250R, THOR22 or MFSK32.
Why accept 5% error when you can have it 100% error free? Are you afraid your typing errors get to the other end undamaged? Rein PA0R > MFSK16 always seems to come up near or at the top of the simulated tests but > I can't duplicate that in the real world. > > My experience is that Olivia 8/500 does as well if not better and gives MUCH > greater latitude in tuning while still providing 100% copy under moderate to > poor conditions. Olivia 16/500 is much slower but goes way into the noise > where I've had terrible results with MFSK16 under the same conditions. And > if 8/250 Olivia (slower yet) doesn't do it, I just turn off the HF rig. > > BTW, my experience is almost all on 80m with NVIS antennae. > > -Dave, KB3FXI > > > --- In digitalradio@yahoogroups.com, Wes Cosand <wes.cos...@...> wrote: > > > > I have finished a series of simulations looking at the performance of > > several modes that seemed appropriate for extended keyboard to > > keyboard rag chew QSOs. I was looking at modes that offered a > > throughput of about 40 wpm so they could keep up with a reasonable > > typist with a bandwidth of no more than 500 hz. > > > > I used PathSim to measure accuracy of text transmission under white > > noise and CCIR 520-2 "Poor" simulated propagation conditions. I > > measured text accuracy over at least seven minutes of text for each > > data point. > > > > The graph can be found at > > http://mysite.verizon.net/wz7i/modeimages/Digital%20Modes%20Poor%20Condx.png > > The methodology, including software packaged used, is outlined at > > http://mysite.verizon.net/wz7i/digitalmodes.html > > > > Summarizing, I arrived at the following SNR (db) for a character error > > rate of 5%: > > > > AWGN "Poor" > > DonimnoEX8 -15.3 -3.1 > > MFSK16 -14.7 -8.5 > > PSK31 -13.2 -0.8 > > Contestia500/16 -14.0 -9.2 > > RTTY -9.1 +3.7 > > > > I probably need to look at Olivia 500/4 > > > > These data confirm my prejudice about the excellent performance of > > MFSK16. With the extended low tones implemented in several packages, > > the mode is not difficult to tune. > > > > A couple things surprised me. I would have expected DominoEX to do > > better under poor propagation. Another surprise is the difference in > > performance between different software implementations of a given > > mode. A software program may have excellent decoding performance with > > one mode and then have performance with another that is not > > competitive. The above numerical data would vary a good deal if > > different decoding software were used. So if you find operating with > > a given mode frustrating, don't discard it without trying another > > program. > > > > I hope that with RSID some of these excellent modes will find greater use. > > > > The web site may well have errors so if you find something surprising, > > please let me know so I can check things. I don't want to mislead > > anyone. > > > > Wes, WZ7I > > www.wz7i.com > > > > > > > ------------------------------------ > > Try Hamspots, PSKreporter, and K3UK Sked Page > http://www.obriensweb.com/skedpskr4.html > Yahoo! Groups Links > > > > -- http://pa0r.blogspirit.com ------------------------------------ Try Hamspots, PSKreporter, and K3UK Sked Page http://www.obriensweb.com/skedpskr4.html Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) <*> To change settings via email: digitalradio-dig...@yahoogroups.com digitalradio-fullfeatu...@yahoogroups.com <*> To unsubscribe from this group, send an email to: digitalradio-unsubscr...@yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
