As a heavy user of AMTOR, mostly ARQ mode though, twenty years ago, I would have to say that this mode is not very robust. There were many times that the signals were still pretty good, but the mode would begin to allow errors to come through (it had a mediocre quality ARQ), or would completely stop any further throughput. The FEC mode is not that good either, but I suppose you wanted it for unconnected broadcasts. And it does not have upper and lower case ASCII code characters.
BPSK is not very robust at all but works well under weak conditions if there is not too many difficulties with the ionosphere. I have had poor results with MT-63 working through severe QRN, but maybe we will have to revisit that mode again to do another comparison. I don't think that we tried the "narrow" 500 Hz version of MT-63. Maybe that would compete well against MFSK16/8 which so far has worked the best for us, even though a pain to get it tuned in. 73, Rick, KV9U Bill Ayer wrote: > Rick, > > We had previously used AMTOR FEC for net traffic. We tried BPSK MFSK > as I remember, and probably some others. More recently also Olivia. > MT-63 seldom fails even under noisy conditions. I can copy it on my > mobile radio with laptop sitting on the seat with no wire connections > at all....and my old Explorer generates considerable RF and road noise > of it's own. > > Under fair to good conditions we use 2000 Hz bandwidth (not a problem > on MARS channels) which is about four times faster and more much more > reliable than AMTOR. For broadcast messages our standard is 1000Hz > bandwidth. When things get too bad for voice communication, 500 Hz > will still generally get through. > > Bill > KB4IJ > > ----- Original Message ----- > *From:* kv9u <mailto:[EMAIL PROTECTED]> > *To:* digitalradio@yahoogroups.com > <mailto:digitalradio@yahoogroups.com> > *Sent:* Friday, April 06, 2007 7:59 AM > *Subject:* Re: [digitalradio] Alabama MARS has changed to MT63 > > Bill, > > What other digital modes did you compare it to and why did you find > MT-63 superior? > > 73, > > Rick, KV9U > > Bill Ayer wrote: > > That's correct. Alabama Navy MARS for some years now, and many > other > > states both Army and Navy use MT-63 for net traffic. It is far > > superior to any other method we've found. > > > > Bill > > KB4IJ > > > >
