According to the terms of our licenses, each of us is supposed to have read and
understood part 97 of the FCC rules and regulations. Here's a summary of the
upper limits for RTTY/data emissions in 97.305 and 97.307 as I read it:
1.8-24.99 MHz: 300 baud with 1 kHz shift or facsimile with 500 Hz maximum
bandwidth
28-29.7 MHz: 1200 baud with 1 kHz shift or facsimile with 500 Hz maximum
bandwidth
50-144 MHz: 19,200 baud, 20 kHz bandwidth
219-220 MHz: 100 kHz bandwidth
222-450 MHz: 56,000 baud, 100 kHz bandwidth
1240+ MHz: no limits
The facsimile in HF rtty/data segments exception was put in recently to allow
the use of Hellschreiber. There are no data rate (bits per second) limitations
on any frequency and no bandwidth limitations on HF except for fax.
For phone/image emssions the rules are different. For 1.8-148 and 222-225 MHz
non-phone emissions are limited to the bandwidth of communications-quality
phone emissions of same modulation type. Given the maximum bandwdths used for
each mode in the past, this presumably means less than 3.4 kHz for SSB, 10 kHz
for AM/ISB and 30 kHz for FM. Note that image includes B7W, B8W and B9W (ISB)
emissions that can contain any combination of rtty, data, phone and image.
There are no baud rate limits. There are no limits at all for 420 MHz and
above, except that emissions must stay within the band.
73,
John
KD6OZH
----- Original Message -----
From: John
To: digitalradio@yahoogroups.com
Sent: Thursday, October 29, 2009 21:50 UTC
Subject: [digitalradio] Re: Why would anyone
Maybe I am growing a little bit confused here .....
As I follow this thread, am I hearing that there is a flat limit of 300 baud
in all aspects of amateur radio?
First, can't we use 1200 baud in certain cases, such as above 2 meters?
Second, how do we correlate the 300 baud limit when we use such tools as
EZPal and other file transfer programs/protocols?
Am I to understand that these are working at a maximum symbol change rate of
300 baud?
guess I better do a whole lot more reading because this is getting quite
complex now ....
--- In digitalradio@yahoogroups.com, "John B. Stephensen" <kd6...@...> wrote:
>
> The baud rate limit applies but this means 300 symbol changes per second on
> each subcarrier. The number of subcarriers and the number of bits per
> subcarrier is not limited. The ARRL regulation by bandwidth proposal was a
> better method than the current regulation by content rules but was opposed
> by too many people.
>
> 73,
>
> John
> KD6OZH
>
> ----- Original Message -----
> From: Charles Brabham
> To: digitalradio@yahoogroups.com
> Sent: Thursday, October 29, 2009 13:02 UTC
> Subject: Re: [digitalradio] Why would anyone
>
>
> John:
>
> Do the rules specify that there is no baudrate limit upon FDM modes?
>
> The fact that they are mentioned does not necessarily imply that they are
> not intended to fall under the 300 baud restriction.
>
