[RTTY] ARRL attack on current RTTY users

[Joe Subich, W4TV]

On 11/20/2013 8:48 PM, Kai wrote:
> No one gains, no one loses, we all win with simplified regs and we
> all win with potentially efficient future digital modesthat could
> operate in reduced BWs, say around 4-500 Hz, unhampered by today's
> needless artificial baud-rate restrictions that predate modern
> computers.

The entire problem with this argument is that 2200 Hz or 2800 Hz is
not what the Commission *intended* when the current regulations were
written.  The *intent* of the 300 baud regulations were to keep the
occupied bandwidth consistent with other narrow band modes - e.g.,
CW and 170 Hz shift RTTY.  Commission representatives at that time
even told many of us who were working on such "new" modes as HF packet
that the *intent* was to keep signals less than 1 KHz *MAX* - as was
the case with the original 850 Hz shift RTTY - and their preference
was that bandwidths be maintained at less than 500 Hz (consistent with
300 baud and 200 Hz shift packet and the original PACTOR systems which
were based on AMTOR/SITOR).

If the *intent* of this proposal is to eliminate an "outdated" symbol
rate requirement, it should have been structured with a 500 Hz target
bandwidth in mind - certainly *no more than 1 KHz* in the beginning.
Instead, this proposal serves only to promote PACTOR 5 or 6 with ever
wider signals and ever greater interference footprints from the
auto-responding systems.

If one wants greater bandwidth, at least have the decency to face the
issue *honestly* and reintroduce "regulation by bandwidth" and place
those 1 - 3 KHz wide signals in the spectrum which currently have
permitted bandwidths up to 6 KHz.

The bottom line is that 2.8 KHz signals are *not compatible* in an
area where 2 KHz can contain 16 to 18 PSK31 signals, a dozen JT65
signals, more than two dozen JT9 signals or a half-dozen traditional
RTTY signals.  Between regulation and gentlemen's agreements or band
plans, most of the US HF bands have less than 30 KHz available for
narrow digital modes - and the non-traditional (WARC) bands have half
that or less.  Just as the Commission has held for 60 years that it is
good policy to separate wide band (voice) modes from the narrow band
(CW/RTTY/DATA) modes, it should not take the chance that a relatively
few "high symbol rate" digital signals to might monopolize the limited
spectrum allotted by regulation for digital or expand further into the
spectrum heavily utilized for CW operation.

The Commission recognized the wisdom of protecting the many from the
few when it limited the spectrum available for automatically controlled
digital systems in the late 1980s and should again reaffirm what it has
understood for 80 years by answering the ARRL's absurd petition with
regulations that replace the "outdated" symbol rate limits with a 500
Hz bandwidth limit in the current "data" allocations.

73,

    ... Joe, W4TV


On 11/20/2013 8:48 PM, Kai wrote:
> Hi Chen
> While I personally agree with you about much lower BW in a clean-slate
> world, consider the following.  If the ARRL had chosen 2200 Hz instead
> of 2800 Hz, their proposal would have affected absolutely nobody. The
> current 2200 Hz users would continue to do their 2200 Hz thing in PACTOR
> (2K20J2D ITU-R/FCC designator) or whatever. The ONLY immediate change
> would be that the regulations themselves would have drastically
> simplified language, by removing arcane 1980's baud-rate language.
> That's a good thing.
>
> There are plenty of things that could/would/should/might and
> had-ought-to-be improved in ham regs, as others have pointed out. But
> this proposal, and this debate, is very simple and very limited. It
> would remove the baud-rate definitions and just define digital in terms
> of a max BW. So max BW is really what's under debate. If you want to
> take away the current privileges we all have, and ask hams to give up
> all of their PACTOR modes (their lowest mode looks like RTTY with a 740
> Hz shift), than choose 500 Hz or some number near that (which would also
> wipe-out RTTY for shifts above 425 Hz). If you want things to stay
> pretty much as they are today, and let the PACTOR guys do their thing as
> they are today, then ask for a 2200 Hz. The ARRL opted for 2800 because
> that number is already in the regs for permitted digi-modes in the 60 m
> band channels. It keeps the regs simple. Note that 2800 Hz may be out of
> reach for the vast majority of today's HF ham transceivers - typical TX
> BW is usually less than 2600 Hz. Check the TX BW specs on your rig!
> (Not you Chen, I know that you use a very modern, very flexible SDR
> radio that can handle the wider BW on TX and RX).
>
> I think that it's really simple, there is nothing hidden or nefarious
> that I can see, or that anyone has specifically point out. If push came
> to shove, I'd opt for a 2200 Hz limit because 2200 keeps the status quo
> - and that could win over the proposed ARRL number. No one gains, no one
> loses, we all win with simplified regs and we all win with potentially
> efficient future digital modesthat could operate in reduced BWs, say
> around 4-500 Hz, unhampered by today's needless artificial baud-rate
> restrictions that predate modern computers.
>
> Cheers and 73
> Kai, KE4PT
>
> On 11/20/2013 6:32 PM, Kok Chen wrote:
>> On Nov 20, 2013, at 3:01 PM, Kai wrote:
>>
>>> I think that discussion should center around what the BW limit
>>> [should] be for digital signals. The answer will likely be something
>>> between 2200 Hz and 2800 Hz, because signals as wide as 2200 Hz are
>>> already permitted. It's good to discuss this.
>> For conversational (keyboard, human-to-human) digital modes, 300 Hz to
>> 500 Hz is ample, and wide enough to use statistical detection methods
>> that take advantage of the frequency diversity aspects of selective
>> fading on the HF bands.
>>
>> 300 Hz is also sufficient to do weak signal experiments to your
>> heart's content.
>>
>> The only reason anything wider is needed is to transmit massive
>> amounts of "data" or digital voice.
>>
>> Unless there is some enforceable rule that controls mutual
>> interference between conversational mode users and data mode users,
>> the proposed change by the ARRL only opens all of us to even worse
>> QRM.  Even a 1 kHz signal in the midst of an RTTY contest or pileup
>> can completely ruin it.  That is what is so wrong with the ARRL proposal.
>>
>> 73
>> Chen, W7AY
>>
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