Something I never have quite understood is that in the late 90's in Indonesia, hams have used 1200 baud satellite PSK modems on 40 meters with seemingly good results.
It has been a bit hard for me to follow that. Does anyone have a sensible explanation for this to be useful. I do not own such a modem, nor found anyone on those days to gove it a try. And I had almost forgotten about it. It seems that a 16 dB adventage for PSK125 is not trivial...it will work when the other won't or will work equally with 40 times less power... 73 de Jose, CO2JA KV9U wrote: > According to the information in the help files from Multipsk: > > 1200 baud Packet = 1320 wpm > > BPSK125 = 148 wpm capital and 204 wpm small letter average speed at > about -8 db S/N > > Of course this assumes that both have good signal strengths and there > are no hits. If the PSK125 mode takes a hit it keeps on sending and > the receiving station gets errors. If the packet receiving station > gets errors, it requires retries and since this mode also requires > much greater signal strength to operate, it can easily have zero > throughput and time out eventally after many retries. Packet may need > something like +8 db S/N to function. This means it is about the same > or slightly worse than the OFDM mode used in digital SSTV programs. > > Anyone else have more real world numbers? > > 73, > > Rick, KV9U > > Walt DuBose wrote: > > > Here is an interesting question... > > > > What is the user throughput in WPM or CPS (what you see on your > > monitor) in 1200 baud AX.25 and the 190-200 WPM user throughput of > > PSK125? > > > > I have send many, many pure SMTP messages using sendmail over AX.25 > > KISS mode with a NOS stack. > > > > I have also worked with HTML message/E-Mail templates and find only > > a couple hundred characters different in the template > > E-Mails/messages and those that are full and complete E-Mail such > > as used by sendmail. > > > > Walt/K5YFW
