wrote:

...
"The market" spoke very clearly, in the form of comments
to FCC. The CTT proposal was overwhelmingly
opposed. About 7 out of 8 comments on it clearly said NO.
Sounds like a clear message from the market to me!

73 de Jim, N2EY


However, if a new market comes forth, one composed of amateurs with
little or no knowledge of CW and only using digital voice and digital
data transmission--it would be market controlled also, and one would
suspect it would self-correct and frown on the use of the bands for
wasteful analog and cw communications.

Let's face it, digital voice is the only way to go. PSK is too slow for
data transmission of LARGE and multi-megabyte amounts of data, end of story.

An "industry standard" for encryption/compaction and
decryption/de-compaction still needs to come forth to deal with HIGH
transfer rates of digital voice and data transmission and availability
to ALL hardware/software developers/manufacturers be assured to such a
standard(s) ...

Great care needs to exercised when proposing and developing acceptable
schemes to the above, we certainly don't need to create a "tower of
babel" by not having free access to algorithms and standard methods in
common use--and free use and experimentation needs to be right up front
and encouraged--this only holds with the tradition of amateur radio!

Regards,
JS
--
http://assemblywizard.tekcities.com

John Smith I wrote:
wrote:

...
"The market" spoke very clearly, in the form of comments
to FCC. The CTT proposal was overwhelmingly
opposed. About 7 out of 8 comments on it clearly said NO.
Sounds like a clear message from the market to me!

73 de Jim, N2EY


However, if a new market comes forth, one composed of amateurs with
little or no knowledge of CW and only using digital voice and digital
data transmission--it would be market controlled also, and one would
suspect it would self-correct and frown on the use of the bands for
wasteful analog and cw communications.

I would disagree. Those modes are not wasteful. On the other hand, a
vision of using the HF bands for data transmission would indeed be a way
of filling up our bands pretty quickly, and for not a lot of gain. If
I'm interested in Data Transmission, I would design a system for
frequencies where there is less natural noise - VHF and up. Then
bandwidth issues would be less of a problem too.


Let's face it, digital voice is the only way to go.

I would disagree. What I have seen in digital voice so far offers no
particular advantage over SSB, unless we are talking about digital for
it's own sake. Most schemes that I have seen have some fatal flaws, such
as the received transmission must be received in toto - IOW if you don't
catch the beginning, you don't catch anything. The solution to that
would be channelizing HF, or assigning specific frequencies to Digital
voice. In addition, unless there have been some big advances recently,
Digital voice does not have any particular bandwidth advantages.

Give me a Digital voice mode that I can tune across the band and pick up
a conversation at any point in the transmission, and a 1 KHz or less
bandwidth signal, and then I'll be interested. And of course, I'll need
to see that some other folks are buying the digital radios too, so I'll
have people to talk to.

PSK is too slow for
data transmission of LARGE and multi-megabyte amounts of data, end of
story.

As for PSK, you are correct that it is too slow for data transmission.
But that little 31 baud signal was never intended for Data transmission.
It was intended for correctable text at a rate that a reasonably
proficient typist could tap away at the keyboard in real time. Also a
mode that can be efficiently operated at QRP and lover levels. And for
that, it is an excellent mode.

- 73 de Mike KB3EIA -

Michael Coslo on Fri, 16 Mar 2007 09:42:30 CST wrote:

John Smith I wrote:
wrote:

However, if a new market comes forth, one composed of amateurs with
little or no knowledge of CW and only using digital voice and digital
data transmission--it would be market controlled also, and one would
suspect it would self-correct and frown on the use of the bands for
wasteful analog and cw communications.

I would disagree. Those modes are not wasteful. On the other hand, a
vision of using the HF bands for data transmission would indeed be a way
of filling up our bands pretty quickly, and for not a lot of gain. If
I'm interested in Data Transmission, I would design a system for
frequencies where there is less natural noise - VHF and up. Then
bandwidth issues would be less of a problem too.

I disagree with both of you...:-) For one thing, 300 WPM
equivalent data rate at 170 Hz "Spread" on HF does a
credible job of sending text in only a half-KHz of
bandwidth.

The presumption is that "data" somehow MUST have "perfect"
conditions to avoid errors is false. The BER or Bit Error
Rate rules the show and is a function of noise and
transmission rate (in units per second) and bandwidth.
Claude Shannon used the example of a teleprinter signal on
his seminal 1947 paper...which became boiled down to the
more familiarly-known "Shannon's Law." That was 60 years
ago and Claude wasn't considering OOK CW modes. :-)

"Data" can have a wide BER range depending on the design
of the data coding, all compared data systems having the
same data rate, signal-to-noise ratio, and channel
bandwidth. Forward Error Correction improves the BER
but isn't an absolute necessity.

An example is the ordinary modem we use on-line. If you
have a human handset as well as the modem line, try
picking up the handset and making random noise in it while
the modem is on-line. That's an extreme case, but
survivable without data disaster. You might be surprised
at how well it can survive without messing up the screen.

Let's face it, digital voice is the only way to go.

I would disagree. What I have seen in digital voice so far offers no
particular advantage over SSB, unless we are talking about digital for
it's own sake. Most schemes that I have seen have some fatal flaws, such
as the received transmission must be received in toto - IOW if you don't
catch the beginning, you don't catch anything.

I disagree with that and I have seen/heard many such systems
but - certainly - not all of them. The digitized bit stream
can be structured to enable a receiver to ID it and lock onto
it quickly. It there are lots of tones in the multiplexed
digital signal (such as with OFDM) that should be enough for
an ID and lock-in.

The solution to that
would be channelizing HF, or assigning specific frequencies to Digital
voice. In addition, unless there have been some big advances recently,

The "big advances" have already come, like in the late 1980s.
I'm mentioning a hint to the U.S. military SINCGARS in its
digital mode (with or without frequency-hopping). DSSS
essentially. Such can be slowed down or scaled to reduce its
bandwidth without disabling intelligibility (no encryption
needed or allowed by amateur regulations).

Digital voice does not have any particular bandwidth advantages.

Maybe not, but the decoded voice can be crystal clear all the
way to the threshold point (where it breaks up suddenly). It
sounds like an FM link with lots of amplitude variation, yet
there isn't any decoded speach amplitude variation.

A case in point is HDTV that we've had in this house for a
year. I've put an attenuator in the TV cable line and NOT
see a bit of difference in video nor hear any in the audio
until there is lots of attenuation reaching the threashold
of input.

Give me a Digital voice mode that I can tune across the band and pick up
a conversation at any point in the transmission, and a 1 KHz or less
bandwidth signal, and then I'll be interested.

Those are already in the works.

And of course, I'll need
to see that some other folks are buying the digital radios too, so I'll
have people to talk to.

Hmmm...what if they are thinking the same thing? :-)

Case in point: PSK31, Peter Martinez' clever brainchild was
spread all over Europe and tested by many on the Continent for
four years before it was first publicized in ARRL publications.
Not many in the USA were aware that PSK31 even existed, let
alone proven under "field conditions." Publicity caused its
spread over on this side of the pond.

PSK is too slow for
data transmission of LARGE and multi-megabyte amounts of data, end of
story.

Sorry, John, but you haven't justified any NEED for "large and
multi-megabyte amounts of data" in the amateur bands below
30 MHz. Please think harder on how much data throughput CAN
happen with existing data bandwidths and rates first. It is
quite large, although that is in subjective terms.

As for PSK, you are correct that it is too slow for data transmission.
But that little 31 baud signal was never intended for Data transmission.
It was intended for correctable text at a rate that a reasonably
proficient typist could tap away at the keyboard in real time.

Absolutely so and that was a design goal of G3PLX way back
in the begining.

Also a
mode that can be efficiently operated at QRP and lover levels. And for
that, it is an excellent mode.

Not necessarily true. PSK31 is efficient in terms of bandwidth
reduction versus data rate, still well within Shannon's Law, but
it can be used at high RF powers just as easily as low RF powers.

It seems to me to be Conventional Wisdom (a new form of "CW")
that "high power" in USA amateur bands is associated only with
OOK CW or SSB. All other modes seem to be ignored in the
literature as a general rule. That's not a technical thing,
just a subjective thing of the high-power types' desires. I've
observed that most of them are ultra-conservative (as a general
rule) insofar as mode use is concerned.

Sometimes one has to look "outside the box" of Conventional
[amateur] Wisdom to see where contemporary limits are in the
practical, working sense.

73, Len AF6AY

On Mar 15, 11:38�pm, John Smith I wrote:
wrote:

"The market" spoke very clearly, in the form of comments
to FCC. The CTT proposal was overwhelmingly
opposed. About 7 out of 8 comments on it clearly said NO.
Sounds like a clear message from the market to me!

73 de Jim, N2EY

However, if a new market comes forth, one composed of amateurs with
little or no knowledge of CW and only using digital voice and digital
data transmission--it would be market controlled also, and one would
suspect it would self-correct and frown on the use of the bands for
wasteful analog and cw communications.

If a new market appears, use of various modes will change,
and the new market can propose rules changes to FCC.

If a new market really does emerge, such proposal will
be widely supported in the comments.

However, it seems to me that the "new market" may be
more of an illusion than a reality. We've had PCs in
hamshacks for a couple decades now, and yet the
popularity of analog modes doesn't seem to be declining.

I recall being told, 20+ years ago, that there would soon
be a national highspeed digital amateur radio packet
network using VHF and UHF that would turn HF into a
backup system. Never happened.

As for "wasteful analog and cw communications" - why do
you call them wasteful?

Can a real-time digital voice message be sent in the
width of an SSB voice signal and result in the same
effectiveness? (signal to noise, power requirements, lack of need to
synchronize, tolerance of interference and fading, etc.)?

Is there any non-text data mode (IOW, something you listen to rather
than look at) which can replace Morse Code?

Should AM voice be banned from amateur radio? How
about FM voice?

Let's face it, digital voice is the only way to go.

Why? And which kind of digital voice?

Why can't there be a choice of modes - digital, analog,
old, new - available to hams?

*PSK is too slow for
data transmission of LARGE and multi-megabyte amounts of data, end of story.

Not the end of the story at all.

Yes, PSK31 is too slow for large amounts of data - because
it wasn't designed for that. PSK31 was designed to be a
keyboard-to-keyboard mode that uses very little bandwidth and has
excellent performance with low S/N ratios. It was
meant as an improvement to FSK RTTY for such QSOs.

For real-time (live) QSOs, PSK31 is fast enough.

An "industry standard" for encryption/compaction and
decryption/de-compaction still needs to come forth to deal with HIGH
transfer rates of digital voice and data transmission and availability
to ALL hardware/software developers/manufacturers be assured to such a
standard(s) ...

Yup. And that's the "who's going to tie the bell on the cat" question.
Who will come up with that standard?

That's the key question to the whole issue. Who is going to
do all that development work and then give it away free?
G3PLX and a small group did it for PSK31.

Great care needs to exercised when proposing and developing acceptable
schemes to the above, we certainly don't need to create a "tower of
babel" by not having free access to algorithms and standard methods in
common use--and free use and experimentation needs to be right up front
and encouraged--this only holds with the tradition of amateur radio!

Agreed! And it's already been established as a tradition.
PSK-31 is a classic example. Everything about it is wide
open and free-for-the-download.

OTOH, Pactor 2/3 is not free at all.
Implementing it requires buying a
specific hardware modem that is rather pricey. Some may
say that $600 for a modem isn't much in the scheme of
things, but even if that's true, it's the principle of proprietary
methods that goes against the grain.

btw, there is a downside to all this digital stuff. With
'analog' modes, such as AM, FM, SSB and Morse Code,
anyone with a suitable receiver can hear amateur
communications as they were meant to be heard. Tuning
in SSB requires a specialized technique, and *understanding* Morse
Code requires learning a skill or
using a decoder, but all that is needed to receive them
is a suitable receiver. IOW, they're wide open.

With digital modes, the incoming message is incomprehensible without a
decoding device - usually
a computer. That creates a divide between those who
are equipped and those who aren't.

Some may think this is trivial in a world where computers
are all over the place. And perhaps it is. But it may not
be a trivial thing at all. In the days when AM voice was
*the* voice mode used by hams on HF, amateur radio
got a lot of new hams from folks who heard hams talking
on their 'shortwave' receivers. That source all but
disappeared when SSB replaced AM, because most
SWLs couldn't receive SSB. More recently, we've gotten
new hams from the ranks of the scanner folks, because
they could hear amateur FM repeaters.

Going digital would eliminate most of that.

IOW, watch out for the Law of Unintentional Consequences.

73 de Jim, N2EY

In article .com,
wrote:

Can a real-time digital voice message be sent in the
width of an SSB voice signal and result in the same
effectiveness? (signal to noise, power requirements, lack of need to
synchronize, tolerance of interference and fading, etc.)?

The review of DRM-based digital voice in this month's QST makes a
point of noting that both the WinDRM and hardware-modem-based systems
require a pretty clean, fade-free propagation path in order to perform
well. On less clean paths, they're prone to drop out... I infer that
as soon as the facing or QRM is severe enough to overcome the forward
error correction coding, you lose an entire packet.

Not the end of the story at all.

Yes, PSK31 is too slow for large amounts of data - because
it wasn't designed for that. PSK31 was designed to be a
keyboard-to-keyboard mode that uses very little bandwidth and has
excellent performance with low S/N ratios. It was
meant as an improvement to FSK RTTY for such QSOs.

I've heard of at least two groups who have been working on a PSK31-based
bulk data transmission system - both systems uses both forward error
correction and an ACK/NAK protocol structure. It's not intended for
megabytes of data, but for semi-unattended transmission of modest
amounts of data during emergencies. For example, basic health&welfare
traffic (queries and "We're OK, are in the shelter" responses) can be
entered via online Web forms, the fields converted to a compact
representation and heavily compressed, and then sent out in big
batches via PSK31 or a similar narrow-bandwidth mode.

The idea isn't to replace SSB voice (or CW net traffic) but to
supplement it, reducing the operators' workload and reducing errors.
It's certainly not intended as a substitute for broadband!

Yup. And that's the "who's going to tie the bell on the cat" question.
Who will come up with that standard?

That's the key question to the whole issue. Who is going to
do all that development work and then give it away free?
G3PLX and a small group did it for PSK31.

Agreed! And it's already been established as a tradition.
PSK-31 is a classic example. Everything about it is wide
open and free-for-the-download.

OTOH, Pactor 2/3 is not free at all.
Implementing it requires buying a
specific hardware modem that is rather pricey. Some may
say that $600 for a modem isn't much in the scheme of
things, but even if that's true, it's the principle of proprietary
methods that goes against the grain.

There was some work going on towards an open-source higher-speed
HF-data protocol a couple of years ago - SCAMP. If I recall correctly
it's based on OFDM (like DRM) with heavy use of forward error
correction. The last I heard of it, it had worked out well under
clean-pathway conditions, but wasn't working all that well under
noisy/fade-prone conditions and wasn't yet considered "ready for prime
time" or (as yet) a serious competitor to Pactor 2/3. Haven't heard
anything more about it in the last year or so - it's possible that
development has stalled.

IOW, watch out for the Law of Unintentional Consequences.

a.k.a. "Oops!" :-)

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

wrote in message
oups.com...
On Mar 15, 11:38�pm, John Smith I wrote:
wrote:


[snip]

PSK is too slow for
data transmission of LARGE and multi-megabyte amounts of data, end of
story.

Not the end of the story at all.

Yes, PSK31 is too slow for large amounts of data - because
it wasn't designed for that. PSK31 was designed to be a
keyboard-to-keyboard mode that uses very little bandwidth and has
excellent performance with low S/N ratios. It was
meant as an improvement to FSK RTTY for such QSOs.


My question on this is why would we be sending large amounts of data on
amateur radio? The need for it doesn't exist in general. If it did,
someone would have developed the appropriate digital mode by now.

Dee, N8UZE

On Mar 17, 2:19�am, "Dee Flint" wrote:

My question on this is why would we be sending large amounts of data on
amateur radio? *

I can think of a couple uses for it, Dee.

First there's emergency/public service comms. The served agencies
are used to being able to send emails with sizable attachments through
the usual networks. A mode that would let them do that via amateur
radio
when the usual networks are not available would be a really good tool
in the emcomm toolbox. IMHO it's the thinking pushing WinLink.

Second, there are plenty of times in an ordinary QSO when it
would be good to be able to send a picture, station description,
article, a sound clip, etc. directly by radio, and have it in digital
format at the other end. In the past, such modes as SSTV have
gained limited acceptance because they required lots of extra
apparatus, but with the widespread acceptance of PCs today
the big limitation is software, not hardware.

The need for it doesn't exist in general.

In some cases, if something is presented to people, they
will find a use for it. Look back on predictions about
computers - in the early '50s it was predicted that a half-
dozen or so general-purpose computers would serve all
the needs of the USA, and in the '70s it was said that no
ordinary person would ever need a computer in their home.
Both pronouncements were made by knowledgeable
professionals, and at the time seemed quite reasonable.

Of course "if you build it, they will come" doesn't always
work out.

*If it did,
someone would have developed the appropriate digital mode by now.

I disagree. One of the big problems is that such development
tends to be protected by the developers, and *not* made
open-source. PSK-31 and Linux are exceptions, not the rule.

In the bad old days, the focus was on hardware, and the
idea of controlling a mode-concept wasn't taken too
seriously. SSB, FM, SSTV, RTTY, AX.25 packet,
etc., all came to amateur radio essentially as freebies.
The standard was widely and publicly
available, just meet it and go on the air.

But you can't homebrew
a Pactor 2/3 modem today the way you could homebrew
an SSB rig 50 years ago.

The "bell-the-cat" question is still *who* is going to develop
such new modes and then just give them away for free.
Groups that have tried (TAPR and the spread-spectrum idea)
have taken years without much to show.

All IMHO

73 de Jim, N2EY

wrote:
On Mar 17, 2:19�am, "Dee Flint" wrote:

My question on this is why would we be sending large amounts of data on
amateur radio?

I can think of a couple uses for it, Dee.

First there's emergency/public service comms. The served agencies
are used to being able to send emails with sizable attachments through
the usual networks. A mode that would let them do that via amateur
radio
when the usual networks are not available would be a really good tool
in the emcomm toolbox. IMHO it's the thinking pushing WinLink.

Yes, I agree that this is exactly what's pushing WinLink.

This is one of those areas in which I have very strong opinions both pro
and con. It's almost like the devil on one shoulder and an angel on the
other, each speaking into one ear.

On the pro side, it really makes a lot of sense in theory. If we hams
could offer this kind of capability to emergency agencies, it would
provide a much-needed communications capability in times of disaster.
But it would need to be stand-alone and not depend upon repeaters that
might be out of service, which to me implies HF.

On the con side, a real disaster is the worst possible scenario for
trying to get this technology to work reliably. You're potentially in a
high-noise low-signal poor-antenna situation. The equipment required is
fairly complex, and you need a fair amount of technical knowledge to set
it up. When I build a mental image of someone at a shelter trying to
set up this gear, it's hard for me to see success. Finally there's the
issue of what data gets sent; some of it probably is not appropriate for
transmission using amateur radio.

Second, there are plenty of times in an ordinary QSO when it
would be good to be able to send a picture, station description,
article, a sound clip, etc. directly by radio, and have it in digital
format at the other end. In the past, such modes as SSTV have
gained limited acceptance because they required lots of extra
apparatus, but with the widespread acceptance of PCs today
the big limitation is software, not hardware.

This one I find intriguing. I do think that if the capability existed,
and did not require purchase of hardware in addition to a PC, that it
would be interesting to enough hams to create a critical mass. It
provides an alternative playground for hams who prefer to experiment
using the keyboard of their PC rather than their soldering iron.

73, Steve KB9X

"Steve Bonine" wrote in message
...
wrote:
On Mar 17, 2:19�am, "Dee Flint" wrote:


[snip]

On the pro side, it really makes a lot of sense in theory. If we hams
could offer this kind of capability to emergency agencies, it would
provide a much-needed communications capability in times of disaster. But
it would need to be stand-alone and not depend upon repeaters that might
be out of service, which to me implies HF.

On the con side, a real disaster is the worst possible scenario for trying
to get this technology to work reliably. You're potentially in a
high-noise low-signal poor-antenna situation. The equipment required is
fairly complex, and you need a fair amount of technical knowledge to set
it up. When I build a mental image of someone at a shelter trying to set
up this gear, it's hard for me to see success. Finally there's the issue
of what data gets sent; some of it probably is not appropriate for
transmission using amateur radio.

Another thing to keep in mind that as our infrastructure becomes stronger,
hams will only really be needed in the absolutely worst disasters. Not only
do you have the bad signal to noise ratio and poor antennas, you may be
power limited. People remark on the low power capabilities of PSK31 for
example but they are only looking at transmit power. You really need to
look at power consumption. That means adding in the computer/monitor combo.
One might actually be better off with voice.



Second, there are plenty of times in an ordinary QSO when it
would be good to be able to send a picture, station description,
article, a sound clip, etc. directly by radio, and have it in digital
format at the other end. In the past, such modes as SSTV have
gained limited acceptance because they required lots of extra
apparatus, but with the widespread acceptance of PCs today
the big limitation is software, not hardware.

This one I find intriguing. I do think that if the capability existed,
and did not require purchase of hardware in addition to a PC, that it
would be interesting to enough hams to create a critical mass. It
provides an alternative playground for hams who prefer to experiment using
the keyboard of their PC rather than their soldering iron.

73, Steve KB9X


I agree that the fun of it is the most probable driver. Yet SSTV has not
grown as rapidly as one might expect when it became possible to do it all
with one's computer.

Dee, N8UZE

On Sat, 17 Mar 2007 14:37:57 CST, "Dee Flint"
wrote:

Another thing to keep in mind that as our infrastructure becomes stronger,
hams will only really be needed in the absolutely worst disasters.

There will always be a need because no matter how strong the
infrastructure is, situations will arise that exceed that capability.
Design of public safety communication systems is the specialty of my
engineering firm and I'm all too painfully aware of the real-world
limitations

Example: One of our med center nets is an inter-hospital net that
carries traffic on bed availability, staff availability, and medical
supply status and need to and from the Metro Regional Hospital
dispatch, the "czar" of inter-hospital operation, which directs
ambulances and supply resources to the available facilities. It is
currently staffed by personnel located in another neighboring med
center. The VHF simplex and repeater ham portion (ham stations
located in the Emergency Departments of all the local hospitals) backs
up a system which is a user group on the City of Portland's 800 MHz
trunked system. When things get tight, the trunked system will be
overloaded with police and fire operations, assuming that the system
survives at all. That's where the hams come in.
--

73 de K2ASP - Phil Kane

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon

e-mail: k2asp [at] arrl [dot] net