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RE: Digest Number 96

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  • ke4ppi
    I can only say...regarding Peter s argument against MT63...I am amazed...the devil ...please.... Pete KE4PPI ... From: MT63@onelist.com
    Message 1 of 2 , Feb 1, 2000
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      I can only say...regarding Peter's argument against MT63...I am amazed...the


      -----Original Message-----
      From: MT63@onelist.com [mailto:MT63@onelist.com]
      Sent: Monday, January 31, 2000 06:54
      To: MT63@onelist.com
      Subject: [MT63] Digest Number 96
      Date: Sun, 30 Jan 2000 18:50:52 +0000
      From: Peter Martinez <Peter.Martinez@...>
      Subject: Re: [psk31] MT63

      >From Peter Martinez G3PLX

      I sympathise with Peter Klein about MT63 operation. As some will
      already know, I have strong opinions on this subject, believing that
      MT63 is most definitely NOT within the spirit of amateur radio. I
      base this opinion on the principle that it's possible to have a
      stable equilibrium between competing types of transmission in an
      amateur radio environment ONLY if they cause equal levels of
      interference to each other when they overlap. This may seem a strange
      thing to say, but it's the essential factor in making sure that
      nobody on one mode operates on top of (or too close to) someone else
      on another mode, so this really is the guiding principle behind
      conflict-free diversity in amateur radio activity. It's this
      principle which lies behind the idea of having modes of similar
      bandwidth sharing sub-bands, or, to put it another way, the principle
      of having modes of widely different bandwidth separated in the bandplans.

      MT63 violates this principle. By it's very nature it is designed to
      survive interference, and so it inevitably causes far more
      interference than it suffers when it is "sharing" the same bit of
      band. I put forward the suggestion that this makes the use of MT63
      "unfair". Even if we simply note that it's bandwidth is wide and
      therefore we should operate MT63 in the part of the band used by
      similar width signals (packet, SSB, etc.), this still gives the
      mutual-interference inequality and is still unfair.

      Note that I have no problem with proposed spread-spectrum modes,
      where a section of band is dedicated to wide-band low-rate digital
      operation and this type of operation can survive it's own mutual QRM,
      but MT63 doesn't come into this category. MT63 cannot survive QRM
      from it's own kind and so it has none of the benefits of
      spread-spectrum operation. If we allocated a dedicated bit of band to
      MT63 so that it didn't cause the rest of us any QRM, then it would
      not suffer from QRM from us either and it then becomes completely
      pointless. It's therefore only "doing it's thing" when it's competing
      unfairly with other modes, and as such is an invention of the devil.


      and look for my answer:

      Hello Peter,

      It is interesting to read your message in PSK reflector. Sorry for direct
      mail but my E-mails are not reprinted in this reflector (maybe I'm badly
      subscribed or so...). I must say that I cannot quite agree with all your
      arguments about MT63 vs. hamspirit - I feel that all modes can have their
      position as well as SSB, SSTV, FM or more non-narrowband modes. There is
      very good advantage of MT63 that its bandwith is very sharp delimited. Also
      I noticed that on the background of wider QSO (f.e. 1 kHz) can be realized
      next narrower QSO (f.e. 500 Hz)
      without QRM. Maybe in future the MT63 mode will specified for 28/50/144 or
      higher bands. I am not sure if this mode will be wholesale spreads as RTTY
      or PSK31 - it is not so "natural for DXing" and absolutely unusable for
      contesting. But about digital hamspirit:
      Time from time I'm using Digipan waterfall and observing on digital
      subbands. I have two notes:
      1. Pactor QRM: It is "anonymous" operation - Never I saw any "QRL?" from
      Pactor operators - and very often their signals are very wide. Where is
      hamspirit? Why Pactor BBS (automatic operation) have not exactly specified
      frequencies as VHF Packet BBS? Why IARU is not discussing about it?
      2. PSK31 QRM: I see a lot of very wide PSK31 signals with "clipping"
      especialy on 80 m. Also some of them are two or three times on the band. I
      think the first problem is overdriving (very known and clear) and the second
      one is RF feedback (very problematic because it is not stable status). But
      the basic problem is some aversion of operators opposite to any advice
      (nobody told me about yet....). What hamspirit there? What about some
      Maybe you have not answers for these questions. It is for muse. I understand
      that you are very busy but if something of these things can be cleared, give
      it to reflector, please.

      73 and many thanks for your nice work.

      Josef OK2WO

      What do you about, folks?

    • Coombe Down
      Pete, You would need to live in and operate from Europe to understand the QRM they have to put up with. Adding MT53 to that is not something they need.
      Message 2 of 2 , Feb 1, 2000
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        You would need to live in and operate from Europe to understand the QRM they
        have to put up with. Adding MT53 to that is not something they need.

        Experimenting with MT63 on a quiet band is one thing (and a lot of fun), but
        using it on a regular basis, particularly using it agressively (to put it
        kindly) on an open DX band is out of the question. Even down here - because
        we have very good LP propagation to Europe that causes them just as much


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