From Peter G3PLX
This is strictly-speaking off-topic, but the subject potentially affects ALL
narrow-band digital modes, and that includes PSK31, RTTY, Pactor 1, Pactor 2,
and I will include CW too just for completeness.
The company SCS which manufactures the PTC digital mode terminal, and which
invented Pactor, has now released the latest Pactor-3 mode, which can be
retro-installed into existing PTC-2e hardware, and will be available in new
This new mode is much wider bandwidth that Pactor-1 or Pactor-2. It can be up
to 2.4 kHz wide, so that makes it as wide as an SSB emission. If mode-3 is
enabled in two Pactor-equipped stations, one Pactor station calling the
other on a channel which is 500Hz wide with other QSOs either side, could
switch without warning to 2.4 kHz wide, WITHOUT CHECKING THAT THE ADJACENT
CHANNELS ARE CLEAR. It is therefore very important that PT3 is ONLY used on
channels which are 2.4 kHz wide
before the QSO starts.
The present worldwide bandplans do not distinguish between digital modes of
different widths, they just say that all digital modes should operate in
specific bands. I have informed RSGB about the latest developments, and asked
them to inform IARU and debate this urgently at the next IARU meeting. If
nothing is done to change the bandplans, there will be a great potential for
conflict. I believe that the intention of the
bandplans has always been to keep modes of different widths separate, and
that this intention has always been met in the past, but only because digital
modes were always narrow-band. Now that there will be wide digital modes, I
think we need to change the way the bandplan is worded, so that we CONTINUE
to separate wide and narrow modes. THIS MEANS PUTTING PT3 HIGHER IN THE BAND
THAN THE PRESENT NAARROW-BAND DIGITAL MODES.
In fact on the popular amateur bands, 80, 40, 20, this can be done without a
change, at least it can in the region 1 IARU bandplan, because the sections
3600-3620, 7040-7045, and 14101-14112 are already shared between digital
modes and SSB.
I would therefore ask anyone who receives this reflector to copy this message
to other discussion groups, especially those concerned with all narrow-band
amateur modes including PSK31, RTTY, Pactor, and CW, with the intention to
agree that ALL Pactor-3 activity should be inside the sections of the bands
that I have shown above, and certainly NOT below 3600, 7040, and 14100 where
narrow-band modes are normally used. In the case of 10MHz, it is well-known
that this is a shared band and the IARU bandplan prohibits SSB because of
this. PT3 should therefore also be
prohibited on this band. This may all change in September if there is some
IARU resolution agreed at the next IARU region 1 meeting.