[RTTY] ARRL attack on current RTTY users

[Joe Subich, W4TV]

Chen makes the point here ... there is no *need* for increased symbol
rates.  The basis and purpose of the Amateur Service can be more
than adequately filled with the current symbol rate restrictions in
place.

1) there is no benefit to symbol rates greater than 100 bps for person
    to person communications, e.g. "keyboard" communications that are
    the basis of the "international goodwill" portion of the Amateur
    Service basis and purpose.
2) 300 bps communications proved to be more than adequate for store
    and forward messaging of short non-commercial, non-time critical
    traffic like personal greetings, and the other messaging typical
    of amateur radio (e.g., ARRL's "National Traffic System") when
    used - in conjunction with "channel busy" detection in the ARRL
    sponsored "automatic operation" STA in the mid 1980's.
3) with wide access to commercial data systems, there is no need for
    amateurs to be passing large volumes of file based traffic via HF
    and even the proponents of higher symbol rates are using commercial
    networks for their "backbone".
4) the overwhelming majority of "state of the art" amateur development
    in the last 20 years has been centered on low symbol rate protocols
    (and narrow bandwidth) - such work by Chen and others to improve
    "RTTY" decoding, G3PLX's work in developing PSK31 and work by Nobel
    Laureate Dr. Joe Taylor, K1JT in developing several extreme weak
    signal protocols.  All of these advances are *adversely impacted* by
    interference from the high symbol rate, wide bandwidth systems
    operating in auto-responder mode with *no* effective "channel
    busy" detectors.

Replacing the symbol rate limit with any occupied bandwidth standard
greater than 500 Hz would only serve to worsen already overcrowded
conditions in many of the "Data/RTTY" sub-bands and encourage more
interference to both person to person communications and those new
protocols that are advancing the state of the art.

73,

    ... Joe, W4TV


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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