Hi johnruexp,
I find it interesting that you picked the year 1931 to ask about
ship-to-shore communications, as this was the year that started the
tremendous surge in Naval and radio communication technology, thanks
to preliminary work done by Marconi! Though not related to ships, in
1931, the Pope made the first broadcast to Catholics, the world over,
using a shortwave radio, while Marconi supervised.
As early as 1912 all military ships were required to use wireless
(non-voice)radios. ?Following the sinking of the Titanic, the U.S.
Congress amended the Radio Act of 1910 to require all ships to carry
radio equipment staffed 24 hours a day? These radios did indeed use
Morse Code. (The first complete transmitted Morse code message was
sent in 1844)
http://www.ibew.org/stories/02journal/0203/techbeat.htm
http://www.qsl.net/n7jy/radiohst.html
?When the wireless (radiotelegraph) was invented, the Navy saw a
possible use for it. It could be used for communications from shore
stations to ships along the coast. In 1899, the first official naval
radio message was sent from ship to shore. It only traveled a distance
of 20 miles but that was a start. The next advance was in 1916 when
the Navy first used radiotelephone between ships. Three years later
the first airborne radio was used to communicate with a ground
station. In the early years, communications was not the best because
of poor tuning techniques. Receivers often did not pick up the signal.
This problem was almost eliminated in 1931 when the first
superheterodyne receivers were installed in the fleet. In 1944,
another important event took place. The first successful radio
teletypewriter transmissions between ships were completed. The first
successful use of radiophoto (facsimile) occurred in 1945 with the
transmission of the surrender document signing that ended World War
II. Naval communications has grown tremendously in size and complexity
since then.?
http://www.tpub.com/content/neets/14189/css/14189_15.htm
?SHIP-TO-SHORE.?This application of the hf band is more difficult than
point-to-point since the ship is moving and constantly changing its
position. In ship-to-shore the path length and direction are variable.
Aboard ship, limited space and other restrictions prohibit
installation of large, efficient hf antennas. Because of the mobility
of ships, shipboard antennas are designed to be as nearly
omnidirectional as possible. Our problems are not as severe at the
shore terminal where we have sufficient space for efficient
omnidirectional antennas or arrays designed for coverage of large
areas of the earth. At shore stations, rotatable, high-gain antennas
or fixed, point-to-point antennas are used. For example, a rhombic
antenna ashore may work well for long-haul, ship-to-shore
communications when the ship is within range of the antenna.?
http://www.tpub.com/content/neets/14189/css/14189_28.htm
?The first development in radionavigation was the Radio
direction?finder (DF) which became compulsory on some ships as long
ago as 1931. Inevitably, the second World War provided a spur to
developments of radio technology in general, including VHF
communications, but particularly marine radar and radio?based
position?fixing systems. It is at this stage that we can really start
to see how technology begins to really serve seafarers (rather than
only the owners or passengers) and improve safety and operational
efficiency on board.?
http://www.imo.org/includes/blastDataOnly.asp/data_id%3D4865/DigitalConference.doc
?Ship-to-shore hf communica- tions are more difficult because the ship
is moving and constantly changing direction. This change of
direction and severe space limitations aboard ships make the
installation of large, efficient hf antennas impractical. To
overcome these problems, ship-to-shore systems have two major
differences from point-to- point systems. First, shipboard
antennas are omni- directional. Second, several frequencies
are usually assigned for each circuit. If one frequency starts
to drop out, another can be selected to match the
propagation path conditions between the ship and the shore terminal.?
http://www.tpub.com/content/et/14088/css/14088_30.htm
?For ships at sea, it was a totally different matter. Once they were
beyond the horizon, they were totally isolated from communicating with
the rest of the world until such time as they reached the next port or
were able to pass messages via another vessel?
http://webhome.idirect.com/~jproc/rrp/nro_his.html
?The first ship-to-shore two way radio conversation occurred in 1922,
between Deal Beach, New Jersey, and the S.S. America, 400 miles at
sea. However, it was not until 1929 that high seas public
radiotelephone service was inaugurated. At that time telephone contact
could be made only with ships within 1,500 miles of shore. Until 1936,
all American transatlantic telephone communication had to be routed
through England. In that year, a direct radiotelephone circuit was
opened to Paris. Telephone connection by radio and cable is now
accessible with 187 foreign points.?
http://inventors.about.com/library/inventors/blradio.htm
The radiotelegraph in use today has this range ?Radio Officers have
demonstrated that a working range on 500 kHz of approximately 1200
nautical miles during the day is routinely available at sea, while at
night, when signals travel much further, 500 kHz Morse radiotelegraphy
can, and does, span oceans? I was unable to find the ranges in 1931,
but as you might guess, they were less than in 1980!
http://www.qsl.net/n1ea/sos.htm
?As the importance of global communication grew after World War I,
AT&T chose the park to conduct ship-to-shore experiments in which
communications were sent as far as 300 miles off the New Jersey coast.
Three more towers were erected in a triangular pattern and used to
broadcast speech and music for a range of 1,000 miles.?
Weather :
Weather still has an effect on communications! Sun spots and solar
flares affecting the ionosphere, the magnetosphere, and solar wind,
are the biggest cause of interference.
http://www.sec.noaa.gov/primer/primer.html
http://www.noaanews.noaa.gov/magazine/stories/mag93.htm
http://www.islamonline.net/English/Science/2002/04/article05.shtml
Time of day, season, and radio frequency can affect radio
communications ship-to-shore. Radio was also the LEAST desired means
of communications in 1931:
file:///C:/WINDOWS/Temporary%20Internet%20Files/Content.IE5/SLIF05YV/262,4,Radio
Wave Propagation
Here is an illustration :
http://www.noaanews.noaa.gov/magazine/stories/images/finaleffects.jpg
The short answer to your question:
Could a ship communicate with the United States east coast if at sea
in the area of Sumatra? Would this be voice communication or morse
code? Would WEATHER have an effect?
Is:
Yes, but not directly. The ship would make a relay communication, to
another ship, or a land radio, who would relay the message to the US.
Voice radio was in use at the time, but military ships used Morse code
(also for security) for sending messages in 1931. Signals got
distorted due to the movement of ships, weather, time of year, and
ionospheric conditions.
Other related material:
How Marconi was able to send wireless signals (Morse Code) using relay.
http://www.marconicalling.com/marconioverview/life.html
It was using Marconi?s wireless invention that the Titanic was able to send an SOS!
http://www.infoage.org/NBHF-marconi.html
Page 25 of this Silicon Valley History site describes radio communication history:
http://web.mit.edu/ipc/www/03-004.pdf
If any part of my answer is unclear, please request an Answer
Clarification before rating. By doing so, if possible, I may assist
you further on this question.
Regards,
crabcakes-ga
Search Stategy:
S/s communications 1931
Ship-to-shore communications interferences
Ship-to-shore history
Naval ship communications |
Clarification of Answer by
crabcakes-ga
on
11 Dec 2003 23:12 PST
Hi again johnruexp,
Thank you for your patience! I must admit, even though you did not
specify ?military? ships, I went off on a military ship-to-shore
communications tangent while researching your question! My apologies.
I am quite certain that both A & B in your clarification are correct,
but have not found precise substantiating data. Do you know what kind
of signaling equipment this craft used in 1931, the size of, and who
owned the vessel ?
I have searched extensively for definitive data, with no luck. I am
including a bit more information, so you can be assured I am working
on the answer. Hopefully you can bear with me for another day, as I
would like to find more information for you.
Even though voice transmission was available for distances as far as
4,000 miles in the 1920?s, this was not yet available for
ship-to-shore till the late 1930?s. Ship-to-shore communications had
to deal with weather, time of day, season, ionospheric conditions, and
the speed and equipment of the ship. Signals could thus be sent from a
moving ship to land, and the signal could be sent across the
Trans-Atlantic cable to the US.
?Wireless communication between two points is established with the use
of a transmitter and a receiver. The transmitter generates electrical
oscillations at a radio frequency: the carrier frequency. When two
transmitters use (almost) the same carrier frequency, they may
interfere. The level of interference depends on many aspects such as
the distance between the transmitters / receivers, the geographical
position of the transmitters, the power of the signal, the direction
in which the signal is transmitted, and the weather conditions. In
case the level of interference is high, the received signal may drop
below the signal-to-noise ratio, which causes an unacceptable loss of
quality. However, the limited availability of frequencies causes their
reuse by multiple transmitters within one and the same network.?
http://fap.zib.de/flavors/content.html
?By the 1930s, radio use was routine in both the maritime service and
in international work, where it competed with cables. Technological
developments made it possible for large shore stations to stay in
touch with vessels and aircraft wherever they were, including the
"ends of the earth," the north and south poles. This world-wide
network comprised commercial and maritime stations, including those of
the navies and governments of the world, as well as dozens of nations
broadcasting to each other on the "short waves." These high
frequencies were first explored by amateurs, and many more amateurs
continued to use them to experiment and communicate worldwide.?
http://www.outsidelands.org/wireless.html
Some civilian craft had voice radio in the the LATE 30?s, finding
this much easier than Morse code. ?By the 1930s, receivers boasted of
single-signal capabilities. Ships at sea and air-craft in flight
employed small, high power vacuum tube transmitters and receivers, by
the mid 1920s. The lives that wireless had saved at sea multiplied
with the new powers that vacuum tubes gave to radio systems. Amateur
radio operators, as well as researchers, in the early 1920s used
vacuum tube equipment to explore higher and higher frequencies. They
discovered the ionospheric propagation of radio waves that enabled
world-wide communication reliably day and night. Commercial and
maritime operations soon followed these pioneers.
By the 1930s, radio was routine in maritime service, and in
international work, competing with cables. Large shore stations kept
in touch with vessels and aircraft wherever they were, including the
poles. The technology had stabilized into a world wide network of
commercial and maritime stations, including those of the navies and
governments of the world, as well as dozens of nations broadcasting to
each other on the "short waves" that were the high frequencies first
explored by amateurs, and many more amateurs experimenting, and
communicating world-wide."
http://www.perham.org/bartlee.html
The distance from Indonesia to NYC is roughly 10053 miles (16179 km)
(8736 nautical miles)
http://www.indo.com/cgi-bin/dist/place1=@173907/place2=@96565
I'll continue on tomorrow! Regards, crabcakes-ga
|
Clarification of Answer by
crabcakes-ga
on
12 Dec 2003 16:52 PST
Hello again johnruexp,
Once again, thank you for your patience!
I have done an exhaustive search for a definite confirmation that a ?
ship could(sic) communicate with the United States east coast if at
sea in the area of Sumatra?? , and found no documentation that this
could or could not have happened. However, now that I have consumed a
steamer trunk-full of ship-to-shore communications material, I feel I
can safely say:
1) A vessel, equipped with a Morse code transmitter (telegraphy,
radio) could NOT send a DIRECT signal from the Sumatra area to New
York. However, Trans-Atlantic cables had been in place over 30 years
for the period you mention. The signal very well could have traveled
part of its route in that manner, but it probably did not involve
voice at all. If the signal was sent in Morse code from ship-to-shore,
it likely got re-transmitted as Morse code, and not voice. (The
original message was code, not voice)
http://mirror.lcs.mit.edu/telecom-archives/archives/history/underseas.cables
2) The signal used was most likely Morse code. Voice transmission was
possible in 1931, but not likely on a private vessel, for reasons of
price, availability and distance. (It would not reach 10,000 miles.)
Telegraphy using Morse code, in the 30?s used LF, which was able to
follow the shape of the Earth. The range was 200-250 miles over sea.
http://www.alleged.com/radio/Harris/HF-Technology.pdf
3) A vessel, equipped with a Morse code transmitter (telegraphy,
radio) could send a signal to a receiver within its range, who would
in turn transmit the signal, relaying until it reached its
destination.
More information:
?During the late 1940s and early 1950s transatlantic liners provided a
high volume of traffic, all using radiotelegraphy (morse code)
transmissions?
http://webhome.idirect.com/~jproc/radiostor/portis1.html
Telex on Radio
"Telegraphy did not go away on radio. Instead, the degree of
automation increased. On land-lines in the 1930s, Teletypewriters
automated encoding, and were adapted to pulse-code dialing to automate
routing, a service called telex. For thirty years, telex was the
absolute cheapest form of long-distance communication, because up to
25 telex channels could occupy the same bandwidth as one voice
channel. For business and government, it was an advantage that telex
directly produced written documents.
Telex systems were adapted to short-wave radio by sending tones over
single sideband. CCITT R.44 (the most advanced pure-telex standard)
incorporated character-level error detection and retransmission as
well as automated encoding and routing.
For many years, telex-on-radio (TOR) was the only reliable way to
reach some third-world countries. TOR remains reliable, though
less-expensive forms of e-mail are displacing it. Many national
telecom companies historically ran nearly pure telex networks for
their governments, and they ran many of these links over short wave
radio."
http://www.nationmaster.com/encyclopedia/Radio/History
Low frequency waves (below 500 kHz) can bend themselves following
Earth's curvature.
http://www.mikroelektronika.co.yu/english/product/books/rrbook/chapter2/chapter2.htm
"The code may transmitted as an audio tone, a steady radio signal
switched on and off (known as continuous wave, or CW), an electrical
pulse down a telegraph wire, or as a mechanical or visual signal (e.g.
a flashing light)."
http://en2.wikipedia.org/wiki/Morse_code
"Throughout the 1930s this long-range service expanded greatly, with a
gradual decline in the use of the long-wave(short-range) service,
However, new markets were being discovered, including the use of
Portishead by the Morse code operators on the flying boats, passing
traffic from as far away as South America and India. The great liners
were also making heavy use of this new service, and by 1936 Portishead
Radio, now with 4 short-wave transmitters, was handling over 3 million
words of radio traffic with a staff of 60 radio officers."
http://www.qsl.net/g8yoa/history1.htm
?ABOUT RADIO COMMUNICATIONS FROM SHIPS IN THE MID TO LATE 1930s?
http://www.rnzncomms.net.nz/PetersStory/backgroundinfo.html
Hope this information has cleared things up for you! Thank you for
such an interesting, albeit complicated, question!
Regards,
crabcakes-ga
|
