Well Rick, you answered in part my earlier question. I have also observer that MSFK16 is as robust as you say and as error free. G4HPE, Jim Richards, has a paper comparing PSK31, MFSK16 and MT63 (http://www.rsgb.org/emergency/articles/datmodes2.pdf) that was presented at the 2004 DCC.
His conclusion us that for RAYNET operations, MFSK16 and MT63 offer the best low cost (computer sound card) modes. Walt/K5YFW -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 19, 2006 6:07 PM To: [email protected] Subject: Re: [digitalradio] Best Mode for QRP? At this time, when you look at throughput speed, bandwidth taken, character set, and robustness, MFSK16 seems to me to be one of the very best modes. Olivia can be good too, but in order to match robustness, seems to need the much wider BW of at least 500 or even 1000 Hz. MFSK16 is claimed to be 316 Hz wide but can operate down to - 13.5 db according to some accounts, while even 1000 Hz wide Olivia is around -12 db. The tradeoff is that Olivia 32 tones/1000 Hz BWmode is under 25 wpm while MFSK16 averages 42 wpm. There are going to be conditions that Olivia may outperform MFSK16 since the wider BW means you can tolerate a bit more damage to the data with intermittent interference, but since MFSK16 is narrower, you may be able to avoid the interference to begin with. And with MFSK16, if you need more robustness, you can switch to MFSK8 which has claims that it can work down to -15.5 db but at a slower speed tradeoff of 26 wpm. But that is still faster than Olivia and working deeper into the noise. The only other mode that seems possible to beat the digital modes at this time is CW which can work down into -15 to even -20 db with top operators. But most of us probably can not do that. And that would be at a top speed of no more than 20 wpm. For keyboarding, what mode can do -13 or better db S/N ratio, reasonably narrow BW,and at least 40 wpm, with a possible fall back to almost -15 db with a slower mode? Only MFSK16/8 can do this at this time. All these new modes are coming along with some different approaches but they are not really outperforming. Unlike most sound card modes, MFSK16 has a powerful Viterbi implementation and I think that is a significant reason for its excellent performance under difficult conditions. During the recent DominoEX contest, it was interesting that two contesters temporarily switched from DEX to MFSK16 in order to communicate better:) One of the complaints of MFSK16 is that it is difficult to tune. I have never understood this as I find it easier to tune it than some other wider and somewhat amorphous looking modes on the waterfall when they are in weak signal conditions. One very helpful attribute of MFSK16 is the "tail" that shows on screen when it idles. It also has a very distinct idle tone to ID. In fact, it would be good if operators would intentionally allow for some idle time to help other stations lock in on them. By the way, we do not have "channels" on amateur radio except for the 60 meter band so I think you would be far better off to have some what to see the signals on a screen or scope like we used to in the "old days":) 73, Rick, KV9U Eli Criffield wrote: >If you could use only one mode QRP what would be best? Not factoring >in popularity, for the sake of argument assume that everyone is going >to use that mode too. > >Why i ask is it seems it would be possible to build a QRP digital >transceivers complete with a small single board computer small LCD >screen for readout and a small Keyboard For input. > >Something like combining This QRP Kit >http://smallwonderlabs.com/swl_psk31.htm >With this >http://www.embeddedarm.com/epc/prod_SBC.htm > >Seems like you could put something together for about $300 with a >small diople, maybe less if you built lots of them. > >Have it "channelized", maybe 5 or 10 channels controlled by a nob on >the front so you don't need a waterfall to find other people who have >the same setup. > >So what mode would work best? > >k0Eli > > > > > > >Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org > >Other areas of interest: > >The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ >DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) > > >Yahoo! Groups Links > > > > > > > > > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links [Non-text portions of this message have been removed] ------------------------ Yahoo! Groups Sponsor --------------------~--> Something is new at Yahoo! Groups. Check out the enhanced email design. http://us.click.yahoo.com/SISQkA/gOaOAA/yQLSAA/ELTolB/TM --------------------------------------------------------------------~-> Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
