[RTTY] Pactor 3 demo

[Joe Subich, W4TV]

> 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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