[RTTY] Pactor 3 demo

Fri Mar 21 15:09:12 EDT 2014

There is a further "worry" that I have as digital  technology marches forward.
We're 50+ plus years beyond the introduction of simple amateur-RTTY,
and rules have not kept pace with amateur practice.

Yes, I keep harping on the BW loop-hole that allowed appearance of wide
band data-only modes like Pactor 3.  The picture is messier, however.
Icom has established D-STAR technology as a viable alternative to FM
voice and data at UHF and VHF. Their HF-UHF transceivers, however, are
  D-STAR capable in all bands even the HF bands. There are D-STAR
"watering holes" now in the voice sub bands at HF, and there are nets at
HF using D-STAR.

D-STAR is a complex QAM digital modulation scheme that interleaves digital
voice with digital data on the same channel. The signal bandwidth is 6 kHz,
and is well documented (except for a proprietary vocoder).

So, on the one hand, here is precedent for users of a wide band (6 kHz)
digital technology, which has appeared in the voice sub-bands. It is also
simultaneously a data (SMS-like) system. Data and DV can appear simultaneously,
or voice-only or data-only [see N3BAH "D-terminal...", Apr QST].
.
I'm sure that you will agree with me that even just the data portion has no 
business
appearing in the CW/data portions of the bands.  I hasten to add that it has not
appeared outside the phone segments ---- but because of its design
it DOES place a data channel interleaved with the digital voice on the same 
signal -
and folks are using it in the phone segments at HF.  The phone segments are no
longer "purely" phone, they never were, once "image" was allowed up there.

So here's your precedent for pushing the wideband digital technology, voice+data
or just-data to the north side of the data/phone spectrum boundary. Let D-STAR
do its digital voice + data, or for that matter data-only [with the N3BAH device].

Perhaps, based on D-STAR precedent,  we should encourage Pactor  to join D-STAR
in the (previously) phone-only band segments.

-Kai, KE4PT

On 3/21/2014 12:03 PM, Joe Subich, W4TV wrote:
>
>> Prior to the start of the demonstration, at the monitoring station,
>> we observed an existing SSB conversation going on just slightly off
>> the frequency and a CW station calling CQ on the frequency. After the
>> demonstration was complete the SSB station was still there but the CW
>> station was gone.
>
> This is a prime example of the asymmetric nature of interference from
> wide band modes to narrow band modes.  It is *exactly* the reason the
> FCC has, for approximately 80 years, protected narrow band modes in
> between 30 and 50% of each HF amateur band from interference by wide
> band modes.
>
> The Commission restated and reaffirmed that policy when ARRL requested
> that *wide band* image transmissions be included as data.  In WT Order
> 04-104 (FCC 06-149) in 2006, the Commission clearly rebuked ARRL:
>
>> we note that eliminating or relaxing the bandwidth limitation would
>> de facto eliminate the separation of narrow bandwidth and wide
>> bandwidth emissions. We believe that separation of emission types by
>> bandwidth is accepted in the amateur service as a reasonable means to
>> minimize interference on shared frequencies and bands and, therefore,
>> we will not replace the 500 Hz bandwidth limitation with a 3 kHz
>> bandwidth limitation.
>
> In footnote 89 of the same order the Commission expanded on the reasons
> for the separation of wide bandwidth modes from narrow bandwidth modes:
>
>> Separation of emission types by bandwidth minimizes or reduces
>> interference because it protects narrow signals from interference
>> from wide signals. Amateur licensees have accepted this division of
>> spectrum as a method for minimizing interference for as long as the
>> amateur service has been regulated, and no commenter in this
>> proceeding requests eliminating emission segmentation based on
>> bandwidth.
>
> The entire Report and Order in WT 04-104 (FCC 06-149) is here:
> http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-149A1.pdf
>
> Based on the Commission's policy since the 1930's, ARRL *should have*
> simply requested that RTTY and data be added to the list of wide band
> emissions permitted with Phone and image, subject to the bandwidth
> limits in 97.307(f)(2):
>
>> (2) No non-phone emission shall exceed the bandwidth of a
>> communications quality phone emission of the same modulation type.
>> The total bandwidth of an independent sideband emission (having B as
>> the first symbol), or a multiplexed image and phone emission, shall
>> not exceed that of a communications quality A3E emission.
>
> Then the "loophole" that K1ZZ and KE4PT are so concerned about (multi-
> carrier digital systems with symbol rates less than 300 baud) could be
> precluded in the "narrow band" segments simply by amending 97.307(f)(3)
> to specifically include a 500 Hz bandwidth limit without precluding
> any experimentation, development, or deployment of new codes and
> PACTOR 3/4 would be free to compete with other wideband modes.
>
> Note that "regulation by bandwidth" which K1ZZ disingenuously claims
> would be a new regulatory paradigm has, in the mind of the FCC, been
> a fact of life for 80 years.
>
> 73,
>
>    ... Joe, W4TV
>
>
> On 3/21/2014 11:27 AM, Terry wrote:
>> Yesterday a few of us witnessed a demonstration of Winlink using the PACTOR
>> 3 waveform.    A simple one line email was sent from a EOC center in North
>> Texas to one of the Winlink stations in Central Texas around 6:00 PM CST.
>> The demonstration was monitored at a station in-between.   The demonstration
>> was done on 40 meters just above 7.100 MHz.    Prior to the start of the
>> demonstration, at the monitoring station, we observed an existing SSB
>> conversation going on just slightly off the frequency and a CW station
>> calling CQ on the frequency.     After the demonstration was complete the
>> SSB station was still there but the CW station was gone.   The transfer was
>> not timed but it was quick (probably two minutes) .
>>
>>
>>
>> So  I want to retract my earlier comments about Winlink being slow.     The
>> demonstrated QRMing is a concern.
>>
>>
>>
>> Thanks,
>>
>>
>>
>> Terry
>>
>>
>>
>>
>>
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