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VE2HAR > MT63 10.03.05 18:11l 265 Lines 8334 Bytes #-7496 (0) @ WW
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Subj: Re: [MT63] 20 kHz wide Digital Proposal
Path: DB0FHN<DB0RGB<DB0MRW<OK0PPL<DB0RES<ON0AR<VA2HAR<VE2HAR
Sent: 050310/1558z @:VE2HAR.#MTL.QC.CAN.NOAM Laval #:41097 $:65521sentto
Ok...here goes...
Quoting Brian Carling <bcarling@cfl.rr.com>:
>
> OK fascinating Walt, but do explain to me WHY it is that we need
> to send so much high speed data on HF?
If you have no other communications (an assumption), and there is an
emergency, you will be asked to send critical infrastructure communications
for local and perhaps state governments and other emergency communications for
medical assistance and basic governmental and protection and safety
communications. In many instances, these communications will be in the file
format that those organizations use in their operational systems. Your choice
is to take a print out and type out the information into ASCII text or send
the file as is. If you type the information, you will introduce 2-3% typing
errors.
You may be called on to send up to 100 messages a day at about 40KB size.
This was the figure that FEMA put out just prior to Hurricane Andrew.
>
> Wouldn't VHF and satellites do a lot better without ruining things for
> the regular CW and phone operators who need their space?
If you are out of range of VHF as N5LYG is in New Mexico, his only choice is
winLink to get E-Mail back to his family in Houston and other locations.
No OSCAR data forwarding satellites are not available 24X7 that I know of so
that doesn't work. There are commercial satellites, which the Texas Baptist
Men Disaster Relief use in our communications; however, that involves using
the Internet and the Internet in some places you need to send messages to or
from may not have Internet access.
Well its one of these things where a decision needs to be made...do we want to
explore and use newer technologies and advance the communications arts or just
jawbone on-the-air. Besides, I see digital voice replacing SSB within the
next 10 years if not earlier...digital voice is so much better than SSB, all
it will take is one of the major HF rig suppliers including digital voice in
their HF rig to start the change. A 100 watt digital voice rig as the same
"talk power" of a 1 KW SSB rig.
>
> By the way the MT63 signals are 1 kHz wide.
MT63 also has a 2KHz mode which is faster and in the long interleave mode much
more robust than the 1KHz mode.
> We don't need to keep making wider and wider digital signals
> and if the digital audio needs to be 20 kHz wide, what is the point?
The point is developing better communications technology...pushing the
envelope. Faster and more robust data.
What if our efforts against BPL fail and the HF bands have a 24X7 S-9+ noise
level? What will overcome this? Digital voice and robust data signals.
>
> Why do hams need to transmit multiple channels of audio all at
> once? For an English and Spanish simulcast? :- )
No...not the same station but you can pur multiple digital signals in the same
channel space.
73 fer now,
Walt/K5YFW
>
> You wrote:
>
> > Brian,
> >
> > Well yes and no. What the HSMM is suggesting is that you allow up to
> > 20 KHz signals. But we're taking about 56KBPs throughput that would
> > allow one or more voice channels actually multi-mode all on one
> > signal.
> >
> > You might see 56KBPs data but it would only be on-the-air for a short
> > time. The "channel" would be shared.
> >
> > Right now we have MT63 at 200 WPM thoughput on a 2 KHz wide bandpass
> > at a -5 dB SNR on a poor CCIR channel. But we really need to push
> > 800-1200 WPM at the same signal level. I don't see doing that with
> > less than a 6 KHz channel even exploiting some of the new OFDM type
> > modulation protocols being developed.
> >
> > How many CW QSOs running at 20 WPM will it take to produce 1200 WPM
> > error free copy at a signal level that MT63 can copy? These are
> > signal levels that even the best CW operator can't copy a signal at.
> > So the answer is that NO number of CW QSOs can produce the throughput
> > of 1200 BPS, near error free, at a -5 dB SNR on a poor CCIR channel.
> >
> > All this IS possible if we are willing to step out of the box.
> >
> > AND the new modes that will develop will be FAR SUPERIOR to Pactor III
> > or anything being done today on HF.
> >
> > We're also looking at doing much of this work using a computer sound
> > card so separate controller hardware is not needed.
> >
> > 73,
> >
> > Walt DuBose/K5YFW
> > Asst Chairman
> > ARRL HSMM WG
> >
> >
> > Quoting Brian Carling <bcarling@cfl.rr.com>:
> > >
> > > On 8 Mar 2005 at 19:11, David J. Ring, Jr. wrote:
> > >
> > > > I don't think the digital signals they want are 20 kHz wide!
> > >
> > > Want to bet on that?
> > >
> > > There IS in fact a proposal out now for a digiotal mode that IS 20
> > > kHz wide for high speed data transefer on HF ham bands. (as if
> > > Cra... er, I mean Pactor is not jamming the HF bands enough
> > > already!)
> > >
> > > Here it is:
> > >
> > > On Janauary 19, 2005, John Champa, K8OCL,ARRL Chairman, High Speed
> > > Multimedia Networks Working Group, issued the Technology Task Force
> > > report to the ARRL Board of Directors, which includes the following:
> > >
> > > "At a minimum, 20 kHz wide emissions should be allowed in the
> > > following segments:
> > >
> > > 3.58 - 3.725 MHz
> > > 7.035 - 7.125 MHz
> > > 14.065 - 14.15 MHz
> > > 21.08 - 21.2 MHz
> > > 29 - 29.7 MHz"
> > >
> > > Obviously, a *single* HSMM transmission, 20 KHz wide, could
> > > totally wipe out all PSK31, MFSK16, RTTY, and many CW and DX
> > > operations on 80m, 40m, and 20m, where they are now used
> > > worldwide. Dozens of CW QSOS could be obliterated within
> > > one 20 kHz swath. NOT a good idea at all!
> > >
> > > We have never seen such a lack of concern and compassion for the
> > > majority of radio amateur activities as evidenced by the ARRL
> > > Committee on HSMM and ARRL support for Winlink's attempted
> > > domination of the HF frequencies, in both cases, to sacrifice the
> > > hobby on HF for everyone else in order to favor a very small special
> > > interest group.
> > >
> > > I can only hope that they really are coming to their senses at the
> > > top level of leadership, but this is cause for alarm. JIm Haynie
> > > says that they are going to have a new band plan by July. I hope it
> > > is a workable one that averyone can live with. The Winlink/Pactor
> > > mess will hopefully get reined in by this.
> > >
> > > OK back to some fun CW contacts now, and a little less grumbling!
> > >
> > > 73 de AF4K
> > >
> > >
> > >
> > >
> > > << Try MT63 on 80m - great fun!>>
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