The 300 baud limit applies only to the HF RTTY/data segments. In the
phone/image segments below 29 MHz there s no baud rate limit but the bandwidth
is limited by the following parts of 97.307(f).
(1) No angle-modulated emission may have a modulation index greater
than 1 at the highest modulation frequency.
(2) No non-phone emission shall exceed the bandwidth of a
communications quality phone emission of the same modulation type. The
total bandwidth of an independent sideband emission (having B as the
first symbol), or a multiplexed image and phone emission, shall not
exceed that of a communications quality A3E emission.
Given the width of some amateur AM signals on 80 meters, this limit seems to be
10 kHz below 29 MHz.
73,
John
KD6OZH
----- Original Message -----
From: Trevor .
To: digitalradio@yahoogroups.com
Sent: Monday, February 22, 2010 09:18 UTC
Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams
However, there may be scope in interpretation of the regs. Up until a few
years ago many US amateurs were under the impression that you could only send a
maximum of 300 bits per second on HF. What the rules actually specified was a
maximum symbol rate of 300 Baud and, probably because no had thought to do so,
there was no limit specified on the number of carriers you could transmit.
That's how these days US hams can run digital voice/sstv.
