Chen
I finally found non-ARRL info about PACTOR-III. The manufacturer claims an
occupied BW of 2.2 kHz not 2.4 kHz as I used in my argument before. So where I
used '2.4 kHz' before I now put '2.2kHz' - and source the data as the
manufacturer's tech manual. In previous emails I was using the 2.2 kHz figure,
but went to 2.4 erroneously because of the ARRL mistaken claim in the proposal.
My bottom line now reads:
____
I can see a 2.2 kHz BW limit below 28 MHz, and 2.8 kHz above 28 MHz.
If I make comments, they will be to support the ARRL proposal in general, EXCEPT
to modify the ARRL proposal such that Table (c) make no changes, then in (3)
change 2.8 to 2.2; do not delete (4) but instead use the language proposed (3)
with the 2.8 kHz limit.
The net effect of the proposal is most clearly shown in the Table of page 2, the
"Maximum Symbol Rate" column would be deleted, and in the "Authorized Bandwidth"
column, the entry for 160-12 m would be 2.2 kHz (ARRL wants 2.8 kHz), and the
10 m entry would be 2.8 kHz.
The "if I make comments" is predicated on finding and being able to present
credible, cite-able evidence that 2800 Hz would cause harm to current users of
the affected spectra. I emphasize "credible and cite-able" not speculative or
anecdotal. Chen, I think you might have material which may work. Why is 2800 Hz
harmful?
Respectfully and 73,
Kai
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
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