On Mar 23, 2:33�pm, Klystron wrote:
�Paul W. Schleck " wrote:

For example, the Casio WaveCeptor on my wrist:

http://www.eham.net/reviews/detail/2497
receives a ~ 1 Baud Pulse Position Modulated (PPM)
signal from radio
station WWVB in Fort Collins, Colorado, which transmits
on 60 kHz. �It
takes about a minute to send the complete time code
to synchronize my
watch. �Slow? �Yes. �Useful? �Yes, very
much so,
especially when
considering the coverage and reliability that can be
obtained from such
a low-bandwidth, groundwave-propagated, Very Low
Frequency (VLF) signal.

In your model, only a single axis of data is transmitted - the time
of day. That seems like a great deal of infrastructure and energy
consumption to transmit a single data quantity.

Actually, it's a very small infrastructure, and very efficient. I've
been there, btw.

The time standard info is already present at the WWVB transmitter
site, so that's no cost. All that's necessary is a system to encode
it, and the WWVB transmitter and antenna. While an impressive
installation by amateur radio standards, the WWVB transmitter is
not overly large for the wavelength.

But WWVB's 60 kHz signal serves large numbers of clocks of many types
all over North America - by radio. It keeps them all synchronized via
radio, without any user intervention.

What alternative technology would do the same job with less
infrastructure and energy consumption?

The equivalent
infrastructure for weather transmission (marine and air) is
even more elaborate and expensive.

Of course. But it's also very important from a safety standpoint.

Can you see that is an outrageously inefficient
way to distribute a small quantity of information?

What alternative technology would do the same job with greater
efficiency?

One of the most current and widely used
communications technologies
among young people

Not just "young people". A lot us find text messaging very useful.

is cellular telephone text messaging:

http://en.wikipedia.org/wiki/Text_messaging

(sometimes also called "Short Messaging System" or SMS)

According to this recent demonstration on the
Tonight Show with Jay Leno:

http://www.youtube.com/watch?v=AhsSgcsTMd4

the realizable data rates are comparable in order of magnitude to th
at
of fast Morse code that can be sent and received by human
operators.

The facts are even more telling.

In that Leno clip, the text messager is the Guinness-book
world-record-holder. The Morse Code ops are a couple of
hams who were going less than 30 wpm - which is less than
40% of the world-record Morse Code speed.

The text messager was allowed to use common text-message
abbreviations, while the Morse Code ops just sent the straight
text with no abbreviations at all.

The Morse Code ops also produced a hard-copy in real time.

IMHO, what was most telling was that the audience was sure
the text messager would win. But a much older technology
proved to be faster.

Just try telling a teenager with an SMS-capable cellular
telephone that
it should be thrown in the trash because it isn't fast
enough, or isn't
of sufficiently novel technology, and see his or her reaction.

The answer will be that it's fast enough for what it's used for.

Isn't that the ultimate test of any technology - that it's good
enough for what it's used for?

My understanding is that they use SMS for fairly trivial
communications, like what they will have for lunch or
where they will meet at the mall.

I can say for a fact that's not true. While a lot of text - and cell
phone - communications is trivial, much is not. For example,
something as simple as a meeting place or time can be
critical information.

A rough equivalence might be SMS users objecting to
the use of the SMS system by people who are sitting at full-size
computers or by people who have connected keyboards to their
phone.

Actually the system can be used that way, in that a message generated
by a cell can be delivered as an email, and the
reverse.

The point is that speed isn't the only criterion.

To give you an amateur radio example, the Automated Position Reporti
ng
System (APRS):

http://www.aprs.org

uses 1200 Baud AFSK packet. �Faster, but still an order of magni
tude
slower than technologies you imply should be thrown out.

� �Again, it is for the exchange of a single axis of data
-
geographic
location. Please stop tying to pass off these single purpose,
dedicated
systems as examples of general purpose communications.

No one is trying to do that. The point being made is that speed
is not the only criterion.

What is meant by "general purpose communications"? My computer
allows internet access, email and some other things, but I still have
POTS and a cell phone. TV and radio come to my house over the air.

I'm not sure that I understand your line of reasoning here.
�You are
implying cause-and-effect. �In other words, use and
advocacy of Morse
code somehow directly contributed to the obstruction of other
technologies. �Can you give direct evidence of specific
examples?

Hams used to deride digital communications as "pulse"
and tell tales
about the way that it squandered bandwidth.

I don't know any hams who used the term "pulse" to refer to
digital communications. Nor have I heard tales about squandered
bandwidth.

However, note that not all digital signals are designed with
bandwidth efficiency as the primary consideration. For
example, classic 850 Hz shift 45.45 baud RTTY uses almost
a kHz of band to transmit about the same info (actually
less) as PSK31 which uses maybe 50 Hz.

They made it out to be
something along the lines of spark-gap.

If you mean spark, I have not seen that comparison anywhere.
Could you provide a specific reference?

Look for articles about "pulse"
communications in old (1960's and 70's) issues of QST and
Popular Electronics.

I have all the QSTs back to the mid-1920s, and have read all
of them. I do not recall any comparison of digital modes to
"pulse" in any of them. Could you provide a specific reference?

I do recall some QST articles back in the 1950s *advocating* pulse
modes for use at microwave frequencies. The idea was that
rather than trying to adapt lower frequency narrow band techniques to
the microwave bands, broadband/radar techniques would be used for
communications.

Considering the lead time needed to develop a new mode, I
think it is unreasonable not to go back at least that far.

PSK31 was developed in a few years by G3PLX and a small group of hams
around the world. Lots of other examples.

I believe
that the anti-digital curmudgeons delayed the implementation of
digital
modes by a matter of decades.

How was this done?

The main impediments to the implementation of digital modes by
amateurs (at least in the USA) were two:

1) Restrictive regulations, brought about mostly by the FCC's need
to be able to monitor amateur transmissions. However, note that
digital transmissions other than digital voice are not allowed in the
US HF 'phone subbands - which comprise the majority of the
bandwidth on those bands. Those rules force the digital
data modes to share only with Morse Code users.

2) The high cost of hardware. Only a decade ago, a PC
was a significant investment compared to a ham rig.

It is interesting to note that the most
widely used digital modes (for 2-way radio, not for broadcast)
were
developed either in Japan (Icom/JARL DV) or under the auspices
of a
police organization that has no ties to radio, except as consumers (APCO
25).

They were developed for specific applications, though. Not for general
purpose use.

Furthermore, if the only technologies that you believe
should be saved
from being thrown away are those at 14.4 kBaud and up,

Can you point to something in my post that makes such a claim?

The statement about throwing 14400 modems in the garbage.

The
only technology that I have derided as being too slow as to have
value
is Morse code that is sent by hand (less than 100 baud).

PSK31 and most HF RTTY are also less than 100 baud. Are they
too slow to have value?

The Navy shut
down its VLF network on the grounds that the data rate
was inadequate.

But amateur radio isn't the US Navy. IIRC, the purpose of that
network was/is to communicate one-way to submerged missile
submarines.

Perhaps it is time for the amateur community to take a similar
step.

What form would that step take? Should amateurs simply not
*use* Morse Code any more?

The *test* for the mode was an issue of great contention among
radio amateurs. But until July 2003 the ITU-R treaty prevented
complete elimination of the *test*.

However, as far back as 1990 it was possible to get any US
amateur radio license with just a basic 5 wpm Morse Code
test and a doctor's note. Since April 2000, no doctor's note
has been needed, and since Feb 2007 no Morse Code test
at all.

How any of this has impeded the development or implementation
of digital modes is unclear to me.

those
technologies are only practically realizable on amateur radio
bands at
high VHF and up. �Such bands have been open to licensees
without need of
a Morse code test for going on 17 years now. �Even before
then, these
bands were accessible to Technician-class amateurs since
at least
shortly after World War II, with a license that only required
a minimal,
5 WPM (essentially individual character-recognition)
Morse code test.

The Technician class license was created in 1951. Its Morse Code
test was always 5 wpm, until it was dropped completely in 1991.

IOW, as has been pointed out, practically all of the US amateur bands
above 30 MHz have been available for the development and
implementation of digital modes by amateurs, with no need for any
Morse Code test. Lots of bandwidth, too - all those bands except
222-225 are wider than all the HF/MF amateur bands combined.


73 de Jim, N2EY