Tom, MT-63 is publicly documented at: http://www.arrl.org/FandES/field/regulations/techchar/MFSK.html Paul -----Original Message----- From: Tom Frenaye <frenaye@pcnet.com> Sent: Apr 8, 2004 10:27 PM To: arrl-odv <arrl-odv@reflector.arrl.org> Subject: [ARRL-ODV:10438] Re: MT63 At 05:57 PM 4/8/2004, you wrote:
Do we have a policy on the use of MT63? I'm having a problem buying into it due to the wide bandwidth when you can almost do the same thing (KB to KB) with PSK31.
I'm getting some flack from the field that we (The ARRL) are not supporting its use.
I found 42 references to MT63 using the ARRL web site search engine. The first one was the January 2004 QST article written by Steve Ford --> http://www.arrl.org/members-only/tis/info/pdf/0101050.pdf The last paragraph of the MT63 section says: "There is a certain amount of controversy surrounding MT-63 in the amateur community. In the most robust form of MT-63, the signal is quite wide (1 kHz). With crowded conditions in the HF digital subbands today, the movement has been toward narrow signals. PSK31, for example, is only about 31 Hz wide. MT-63 seems to run counter to this trend. Finally, there are legal issues involving the complex MT-63 modulation scheme. As this article was written, the Federal Communications Commission had not declared MT-63 to be a legal mode for US-licensed amateurs." That seems like a good reason to go slowly. In the end the FCC will likely say it's OK as long as the modulation scheme is made public. We'll eventually end up with (HF) modes that vary from nearly zero to whatever AM really is. We haven't had much of the "in between" bandwidth modes until the last few years, either they were quite narrow or quite wide. We have done product reviews of software capable of MT63 --> http://www.arrl.org/members-only/prodrev/pdf/pr0308.pdf We did not even hint that the mode may not be legal in that article. The best I can tell, our policy on the newer modes is to stay out of the way. Several of them, like Pactor-3 have proprietary modulation schemes and are clearly not legal yet, in my view. But the reality is that there is a lot of worldwide and USA use of them the minute they are made available to experiment with. -- Tom ===== e-mail: k1ki@arrl.org ARRL New England Division Director http://www.arrl.org/ Tom Frenaye, K1KI, P O Box J, West Suffield CT 06093 Phone: 860-668-5444