[RTTY] Hints and tips on how to file comments on RM-11708

[Joe Subich, W4TV]

If it is 2.4 KHz wide, it can not be legal ... how can one square
2.4 KHz occupied bandwidth with a rule that states a combined
criteria of 1000 Hz and 300 baud which works our to 1500 Hz?

This is *exactly* the reason that comments need to stress a 500 Hz
bandwidth limit for all "RTTY, data" emissions in the spectrum
covered by 97.307(f)(3) and 97.307(f)(4) to be consistent with
"traditional radiotelepinter bandwidths" as the Commission held
in "Further Notice of Proposed Rule Making, 43 Fed. Reg 36984".

The Commission believed that a 1000 Hz shift and 300 baud symbol
rate would assure emissions consistent with "traditional radio-
teleprinter bandwidths" would provide for bandwidths consistent
with then standard operating practice.  Unfortunately, there was
at that time no use of composite FSK/PSK systems, multi-tone
systems, etc. and their use has exploited a regulatory loophole
*that needs to be closed* lest these wide bandwidth and inefficient
modes cause irreparable harm to traditional narrow bandwidth modes
which are limited to frequencies where F1 emissions are authorized.


73,

    ... Joe, W4TV


On 11/24/2013 9:01 PM, Kok Chen wrote:
>
> On Nov 24, 2013, at 5:02 PM, Joe Subich, W4TV wrote:
>
>> PACTOR III is *NOT* currently permitted under the rules.  Its use has
>> been *overlooked* by enforcement organizations as it *absolutely* can
>> not be justified under the *dual standard* in 97.307(f)(3) which has
>> both 300 baud and 1000 Hz shift limits.
>
> That is not true Joe... please don't make that mistake in your FCC filing.
>
> At all SL levels, Pactor III's symbol rate is fixed at 100 baud (yes, not even close to 300 baud).  (Don't confuse Symbol Rate (baud rate) with data rate (bit rate)).
>
> Pactor III is not 2 tone FSK, so the FSK shift rule does not even apply (makes no technical sense since there is no frequency shift happening).
>
> Pactor 3 SL1 (the slowest rate) consists of two synchronous PSK signals (not FSK), that are separated by 840 Hz.  840 Hz is the maximum tone separation for Pactor 3 (if you want to apply the term "shift" to the signal).  As more tones are added (SL2, SL3, etc), the tone separations become narrow, and at the narrowest, there are 18 tones, separated by 120 Hz from one another.
>
> Pactor 3 SL1, 2 and 3 uses binary PSK, and Pactor 3 SL4, 5, 6 uses Quadrature PSK.
>
> It is much clearer if you go take a look with a panadapter or a waterfall, or if you can, in I/Q phase space.
>
> Pactor 3 SL1 looks like two broad indistinct tones that are 840 Hz from one another, with a distinctive gap in between them.  It is quite unmistakable once you see it on the waterfall.
>
> 73
> Chen, W7AY
>
>