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 >
