There was a study done a couple of years ago I believe by the ARRL that showed accuracy of relaying by SSB was not nearly what it should be, CW (if I remember correctly) was better but still not good. I don't remember FM being nvolved in the test.
If I can find the study somewhere I'll post a reference. The biggest problem on SSB is voice quality. A 2.4khz to 2.8khz bandwidth just doesn't give enough intelligibility to actually tell the difference between some sounds (e.g. f and s). The receiving operator tends to "fill in" with what ever his/her brain provides. So a message of "how many will fit in the Astrodome?" gets turned into "how many will sit in the Astrodome?". Not good. The truly sad part is that the ARRL did not take the next step and actually come up with any proposals to help accuracy. It should be noted that this accuracy is a problem on tactical nets as well as logistical or H/W nets. Instead they started the push to email - which in my estimation was a mistake. Anyway, non-ARQ modes tend to provide the same mistakes that SSB does. You can have an error creep in that isn't noticed and totally change the meaning of the message. If you are sending binary files, it is even worse. ARQ modes are much, much better but everyone needs to understand that they are NOT, absolutely NOT, 100% accurate. I have seen messages delivered by Pactor I get garbled. It doesn't happen often but it does happen. Bottom line? Use the best accuracy you can. ARQ modes are the best for accuracy. The biggest problem you'll find is that ARQ session oriented modes are conducive to net operations. FEC modes, on the other hand, are. It might be a good operating procedure to run a data net like this simlar to a CW net. Send the people with traffic off frequency to use an ARQ mode for passing the messages. Use an FEC mode on the net frequency to coordinate checkins/checkouts. Quick switching between modes would be a primary attribute in such a net. Some things to think about I guess. tim ab0wr On Friday 24 February 2006 16:40, Jason Hsu wrote: > --- In digitalradio@yahoogroups.com, KV9U <[EMAIL PROTECTED]> wrote: > < Very few current sound card modes are ARQ. My experience says that > only ARQ modes should be used for serious traffic handling. > > > Why should only ARQ modes be used for traffic handling? CW, SSB, and > FM are non-ARQ modes, and people use these modes for passing traffic > every day. > > < The name of the net sounds very unprofessional and I am not sure why > you want to select such a name? > > > The Missing You Like Candy Net is the name for my 6m/2m/70cm SSB > ragchew net. I haven't selected a name for the 30m digital traffic > net yet, but I do realize I need a more conventional name for a > traffic net. I'm thinking of calling it "The First 30 Meter Digital > Traffic Net", but that seems to long. > > Jason Hsu, AA0II > > > > > > 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 <*> 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/
