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Old March 24th 08, 03:54 AM posted to
AF6AY AF6AY is offline
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First recorded activity by RadioBanter: Mar 2007
Posts: 229
Default WPM to BPS calculation

Paul W. Schleck posted on Sun, 23 Mar 2008 12:03:58 EDT:

Many types of communications vary over many orders of magnitude of
information rate, yet are considered useful and up-to-date.

For example, the Casio WaveCeptor on my wrist:

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.
The watch only needs to receive the time code at most once per day,
which it does so automatically in the early hours of the morning sitting
on my desk or dresser. A faster data rate would require something other
than a VLF signal, and would not improve much on the quality or
usability of the communications. It would definitely increase the
price. Witness the much greater success in the marketplace of
WWVB-based watches versus more advanced, higher bandwidth, but much more
expensive, "Smart Personal Object Technology" (SPOT) watches:

Good mention, Paul. Ummm...the data rate is rather exactly one bit per
second and takes exactly 60 seconds to send one frame of time and date
data. :-)

ALL the details are given at under the 'Time Frequency'
page, including propagation charts at various times of the day and
for various seasons. This southern California region can regularly
receive enough signal to set radio clocks even if at an approximate
distance of about 900 miles to Fort Collins. In 2005 my wife and I
drove to southern Wisconsin and my La Crosse radio wris****ch never
failed to set itself properly even though some of our overnight stays
were in hotels having steel structures or in among other buildings.
We have two radio wall clocks in our residence and those are exact
enough to compare on-the-second with HF time ticks from WWV and WWVH.

[I won't quibble about the PPM mode descriptor since the full details
of modulation are given at NIST website... :-) ]

According to this recent demonstration on the Tonight Show with Jay

Ahem...quibble mode on...that little bit on the Tonight Show was
a 'setup' gig that employed two young local male actors as the
(described) "text messaging experts" but the two hams (one of which
would very soon become marketing director for Heil Sound) were
real. That is the input I got directly from a reliable staffer on
the Tonight Show. Took a few phone calls to get that information
but it is an advantage of living inside the entertainment capital of
the USA (aka Los Angeles, CA)...and the NBC western Hq is only
about 5 miles south of my place, down Hollywood Way to Alameda and
then east about a mile. That whole bit was really a send-up on the
popular fad of text messaging done by teeners and young adults.

That bit is about as 'real documentary' as Leno's send-ups on the
'street interviews' with ordinary (apparently clueless) younger
folk on various kinds of knowledge. In short, ONLY for gag purposes.

To even give you a Morse code example, consider the simplicity and
effectiveness of the NCDXF beacons running on the HF bands:

HF beacons are neat for their purposes of checking on HF propagation
paths, but they aren't 'communications' in the regular sense. Those
were also designed for simplicity at the various receiving sites but
require rather precise time-of-day at each receiver in order to get
the start of each cycle.

While I had not intended to restart some morse-vs-others kind of
argument, I have to note where I began HF communications with the
US military some 55 years ago. Not a single communications circuit
used any form of morse coding to achieve a throughput of nearly a
quarter of a million messages per month (average in 1955). The
majority was teleprinter of the 5-level 'Baudot' format running at
60 WPM equivalent rates. 24/7 of course with TTY distributors to
to automatically start another p-tape reader when the other reader
was done. FSK 'spread' was then 850 cycles, not the narrower 170
Hz of today. Radio circuits (where I was assigned) spanned the
northern Pacific from Saigon, Seoul, and Manila to Anchorage,
Seattle, San Francisco, and Hawaii.

In 1955 the Army tried an experiment on a few select radio circuits
to push the Teletype Corporation's machines to 75 WPM equivalent.
End result of that was a failure rate more than double that of the
standard 60 WPM equivalent machines. Teletype seems to have achieved
an optimized design for 60 WPM equivalent; their 100 WPM equivalent
next-generation machines used a different electromechanical system,
were quite reliable at that rate.

very fast determination of the link budget to the beacon locations. If
you can't remember what a "V" sounds like in Morse Code (". . . _" like
the intro to Beethoven's Fifth Symphony), I suppose you could put that
on the chart as well. After all, the use of similar charts are how
pilots usually decode the Morse code identifications of aeronautical

Quibble mode on again. The LF aeronautical beacoms are what you are
writing about but they are NOT used much at all for aircraft radio-
navigation now, nor were they a half century ago. Present-day (and in
1962) radionavigation over land is done mainly by VOR (Very high
frequency Omnidirectional Radio range) using a unique 30 Hz antenna
pattern rotation with a reference phase of 30 Hz sent on a 9.96 KHz
subcarrier. Aircraft VOR receivers have used very simple (even for
tube circuits) to determine their bearing to a ground station. These
were simple enough (and low cost enough) for small private general
aviation craft and the US VOR system was adopted internationally in
1955. For distance to a ground station the civil method emplyed a
low L-band interrogator sending a (jittered) double pulse and
measuring the return delay (plus 50 uSec) from the ground station
responder. This DME (Distance Measuring Equipment) was compatible
with military TACAN (TACtical Area Navigation) signal format and the
FAA combined VOR-DME-TACAN equipments on the ground and those are
identified by the contraction VORTAC. On aeronautical charts (from
the government, usually reprinted by private companies) there is
usually a magnetic bearing compass circle (VOR and civil-use-TACAN
reference magnetic reference, not actual north reference)...the
VHF frequencies (DME and TACAN frequencies have been paired with
VOR), ICAO 3-letter ID, and the dot-dash pattern of that 3-letter ID.

The elegant simplicity of VOR is that it will permit AM Voice IN the
ground station transmitter without disturbing the antenna pattern
modulation or the reference phase subcarrier. In congested urban
areas where a lot of general aviation aircraft abound, FAA stations
routinely use VOR voice transmissions to aid civil pilots, easing
the pilots' workload by providing extra information such as WX,
special conditions at an airport. My local airport (BUR) now known
as Bob Hope Airport, the FAA used to send a repeating voice
announcement of local WX conditions, airport info, etc., all
identified by a letter, beginning with A or Alpha at midnight. The
tag on the voice tape loop was "please tell the tower you have
received 'information Foxtrot or whatever letter'" when requesting
landing at that airport. Yes, some VORs transmit the ICAO 3-letter
ID as a low-modulation on-off tone in slow morse but I have yet to
find any civil pilot, beginner to experienced, who USES that code
for radionavigation.

Focusing simply on information rate disregards other aspects of the
communications and the channel over which it is transmitted. These
important aspects include the bandwidth and propagation characteristics
of the available channel, the complexity of the required transmitting
and receiving equipment, the amount of data that needs to be
transmitted, and how quickly and often it needs to be conveyed.

Martinez' PSK31 was rather precisely designed for low (500 Hz)
bandwidth coincident with non-typists typing rate of about 30 WPM
equivalent, all in congested Data slices of amateur radio band
'bandplans' on HF. With relatively simple electronic terminal
equipment with microprocessor-aided operation, I/O memory space
and programming is a minor addition to handle faster typists'
input, even burst typing on a keyboard to 100 WPM or so equivalent.

The OLD FSK bandwidths on HF (of a half century ago) took up about
a whole KHz while using an 850 cycle shift. On the 3 KHz of an old
commercial-format SSB channel (one of four), as many as 8 separate
TTY circuits could be frequency-multiplexed. A more reasonable
shift (to 170 Hz) occurred later with improvements in terminal
equipment technology, is the norm now, even for 100 WPM equivalent
teleprinter rates of those still using electromechanical terminals.

BANDWIDTH occupancy seems to be the primary driver for modulation
rates on HF. YMMV.

There are more complex methods of modulation-demodulation that
have been available for some time. DRM (Digital Radio Mondial) is
one such as has been verified on HF for 'SW BC' (Broadcasting).
That DRM has not spread well among broadcasters has little to do
with technical details of modulation-demodulation, but rather in
the poor propagation conditions of this sunspot cycle limiting
broadcasters' range. If a signal can't get through at all, NO
modulation method is going to help. Besides, with the availability
of satellite radio broadcasting, 'SW BC' has gradually shifted
over to that method rather than using HF directly.

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? If
you are implying that licensing requirements obstructed the development
of advanced digital modes, that really doesn't appear to be the case.
Witness the success of Tucson Amateur Packet Radio (TAPR):

It is disingenuous to 'force' an argument by introduction of
something not overtly stated by the originator.

TAPR and its membership have done some excellent technical
development and spread of such technology. Note also that its
membership is made up of radio amateurs who've been licensed for
a while and are NOT technical beginners in radio or electronics.

In the view of the ENTIRE world of radio, not just amateur radio, the
use of morse code modes to communicate has steadily decreased for
over a half century. It has decreased so much so that some non-
amateur radio services either stopped using that mode or never
considered it for a new radio service introduced in the last half
century. As a prime example, the changeover to GMDSS and replacement
of the old 500 KHz international distress and safety frequency which
used morse code exclusively. Even the USCG stopped monitoring that
old 500 KHz frequency. GMDSS was designed and approved by the
Maritime Community, not by amateurs.

The decline, or perhaps more accurately, the failure to keep up
with overall population increase (of USA) amateur licensees is (in
my opinion) NOT due exclusively to 'USE' of morse code. US amateur
radio license totals peaked 5 years ago. In general, by informal
polling, newcomers are NOT embracing morse code modes...nor are
they flocking to HF amateur bands. PART of that MAY be due to the
insistence of the 'amateur radio community' to hang onto the morse
code TEST forever. Part of that is due to the slow acceptance of
international amateur radio to change the international amateur
Radio Regulations away from old standards. WRC-03 of nearly 5 years
ago allowed individual administrations to drop the morse code test
for an amateur radio license. The USA did not follow through on
that until more than 3 years later. [precisely, the end of July
2003 to 23 February 2007]

[in response to 'Klystron']

If you are saying that someone *else* should have developed these
technologies (other than you, of course), and that since they haven't,
then someone *must* be to blame, well, you can't really dictate how the
world should turn out without taking an active role to help make it that

That's rather strong wording from a leading person of this
newsgroup, isn't it?

For a very long while, ever since I first began as a pro in HF
radio communications, PART of the 'amateur radio community' had
been very busy 'dictating' how the amateur radio world should be
by the continuation of the morse code test for an amateur radio
license. OTHERS, including those of us (like myself) who were NOT
licensed in amateur radio have actively campaigned to remove that
test from US amateur radio...even though other countries had
already preceded the USA in abolishing that code test. I won't say
that I've 'been responsible' for any USA changes but I was certainly
'active' in trying to do so. The FCC apparently agreed with some
of my views as well as so many others supporting that test
elimination. It came to pass. But, that coming might have been too
late to change others' interests in US amateur radio.

In my electronics work that began (professionally) in 1952, I've
been involved in a lot of different electronics and modes and
modulations of RF that were never allocated for US amateur radio
use. Some of those just wouldn't apply to two-way communications but
others would apply. There are still some US regulations that need
altering but a very vocal PART of the 'amateur radio community'
seems very adamant about NOT upsetting the status quo. The future
of US amateur radio does NOT depend solely on them.

73, Len AF6AY
First licensed in US amateur radio in March 2007
First licensed in US commercial radio in March 1956
First QSY of a 1 KW HF transmitter in February 1953