Chen
The FCC have also stated that
Note 23 on page 11 of ARRL filing: "As the commission noted in Mark Miller,
supra, changing the rules to prohibit a communications technology that is
currently in use is not in the public interest." [note 21: See the Order, Mark
Miller, DA 08-1082, 23 FCC Rcd. 7449 (2008).
That is why I think that lowest number can be 2200 Hz. That RTTY max combo of
300 B and 1000 S by FCC calculation fro 2 tone FSK would be 300+1.2(1000)=1500 Hz..
Note by doing nothing, future PACTOR like modulations can and will transmit
unlimited BWs, as long as they can find easy access to ham radios that have SSB
bandwidths that are large enough - as for example your SDR radio. As these
become common, they WILL increase the BWs! We need to have a limit - as opposed
to "do nothing".
QRM is not raised in the ARRL ruling, so we should somehow find language shows
BW of even 2200 Hz is already harmful, so we don't want them to increase beyond
that (except above 28 MHz maybe).
73
Kai, KE4PT
On 11/24/2013 11:00 PM, Kok Chen wrote:
On Nov 24, 2013, at 7:40 PM, Dave AA6YQ wrote:
A stronger argument is that no increase in bandwidth should be permitted until
the issue of QRM from automatic stations has been
resolved.
I agree.
But we need to settle on what "increase" means. What is the baseline of the
increase?
If you use 1000 Hz FSK shift at 300 baud, that comes up to a bandwidth around
1250 Hz (I guess you can use the ITU formula to get an ITU approved bandwidth
number that the FCC probably won't argue with). So this is the allowed
bandwidth based on existing rules for an FSK signal.
If you use Pactor 3 as the the gating item, then with all 18 tones active,
Pactor 3 uses 2200 Hz. This is the bandwidth based on currently allowed
equipment.
So, which is it? I think it is somewhere between those to numbers.
73
Chen, W7AY
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