Hello Bill, According to the Multipsk help, it is -5 dB for the 125 bauds (which is logic for this speed). But -5 dB with a gaussian noise (fix statistical characteristics).
73 Patrick " BPSK125 and QPSK125 Creation: in 2003 Description : Baud rate : 125 Speed : 148 wpm in capital letters and 204 wpm in small letters (average) Bandwidth : about 320 Hz, Drift tolerance : 120 Hz/min in BPSK125 and 40 Hz/min in QPSK125 (depending on level) Lowest S/N : -5 dB " 73 Patrick ----- Original Message ----- From: Bill McLaughlin To: [email protected] Sent: Thursday, February 01, 2007 2:11 AM Subject: [digitalradio] Re: FNpsk Hi Rick, I think FNpsk uses QPSK125 and PSK31...but otherwise you are correct as there is no speed difference that I am aware of between BPSK125 and QPSK125....QPSK125 is alot more frequency sensitive then BPSK125 and I think that about -5 db S/N is probably more realistic than -8 db S/N. 73 Bill N9DSJ --- In [email protected], KV9U <[EMAIL PROTECTED]> 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 > > > > >
