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History of radio
The pre- and early history of radio is the history of its technology. See
also the History of Science and Technology. Later, the history is dominated
by programming and contents, which is closer to general History.
Radio's prehistory (19th century)
* 1820 Hans Christian ¯rsted
* Michael Faraday
* James Clerk Maxwell
* Heinrich Rudolf Hertz
In St. Louis, Missouri, Nikola Tesla made the first public demonstration of
radio communication in 1893. Addressing the Franklin Institute in
Philadelphia and the National Electric Light Association, he described and
demonstrated in detail the principles of radio communication. The apparatus
that he used contained all the elements that were incorporated into radio
systems before the development of the vacuum tube.
In 1895, Guglielmo Marconi sent a telegraph message without wires, but he
didn't send voice over the airwaves; Reginald Fessenden, in 1900,
accomplished that. On Christmas Eve, 1906, using his heterodyne principle,
Reginald Fessenden transmitted the first radio broadcast in history from
Brant Rock Station, Massachusetts. Ships at sea heard a broadcast that
included Fessenden playing the song O Holy Night on the violin and reading a
passage from the Bible.
The first benefit seen to radio telegraphy was the ability to communicate
with ships at sea. A company called British Marconi was established to make
use of Marconi's and others' patents. This company along with its subsidiary
American Marconi, had a stranglehold on ship to shore communication. It
operated much the way American Telephone and Telegraph operated until 1983,
owning all of its own equipment and refusing to communicate with non-Marconi
equipped ships. Many inventions improved the quality of radio, and amateurs
experimented with uses of radio, thus the first seeds of broadcasting were planted.
Spark Gap Wireless Telegraphy (1896--1920)
* Quickly becomes popular on ships after the Titanic.
A typical high-power spark gap was a rotating commutator with six to twelve
contacts per wheel, 9 inches to a foot wide, driven by about 2000 volts DC.
As the gaps made and broke contact, the radio wave was audible as a tone in
a crystal set. The telegraph key often directly made and broke the 2000 volt
supply. One side of the spark gap was directly connected to the antenna.
Receivers with thermionic valves became commonplace before spark-gap
transmitters were replaced by continuous wave transmitters.
Audio Broadcasting (1915--)
* Invention of the triode amplifier, generator, and detector enables
Radio broadcasting is born
Westinghouse in Pittsburgh, Pennsylvania and the Scripps' Detroit News in
Detroit, Michigan were the first US broadcasters in the early 1920s.
Broadcasting was not yet commercially supported; the stations owned by the
manufacturers and department stores were established to sell radios and
those owned by newspapers to sell newspapers and express the opinions of the
owners. Westinghouse was brought into the patent allies group, General
Electric, American Telephone and Telegraph, and Radio Corporation of
America, and became a part owner of RCA. All radios made by GE and
Westinghouse were sold under the RCA label 60% GE and 40% Westinghouse.
ATT's Western Electric would build radio transmitters. The patent allies
attempted to set up a monopoly, but they failed due to successful
competition. Much to the dismay of the patent allies, several of the
contracts for inventor's patents held clauses protecting "amateurs" and
allowing them to use the patents. Whether the competing manufacturers were
really amateurs was ignored by these competetors.
* Commercial (United States) or governmental (Europe) station networks
* Federal Radio Commission
* Federal Communications Commission
* Birth of the soap opera
* Race towards shorter waves and FM
VHF television and FM radio both use frequencies on the VHF band.
W1XOJ was the first experimental FM radio station, granted a construction
permit by the FCC in 1937.
FM radio had been assigned the 42 to 50 MHz band of the spectrum in 1940.
The Federal Communications Commission in late 1943 asked the radio
manufacturers to establish the Radio Technical Planning Board, which would
advise the Federal Communications Commission on allocation and other
technical matters. The Radio Technical Planning Board was divided into
pannels on various subjects which would make recommendations to the whole
board, which the board might support. The Radio Technical Planning Board FM
panal recommended that more frequencies should be given to FM in the 50 MHz
area where FM was already assigned and operating. Unfortunately for FM and
the nearly 400,000 FM receiver owners the Radio Technical Planning Board as
a whole did not agree with the panel. The reason the board made this
decision was that it had been given flawed evidence by a former Federal
Communications Commission engineer named Kenneth Norton. He believed that
sunspots, which appear every eleven years, would cause severe disruption to
the FM signal. Norton never explained why television signals at the same
frequency wouldn't be disrupted. The Radio Technical Planning Board thus
recommended that FM radio be relocated near 100 MHz. The Federal
Communications Commission heeded the advice of the Radio Technical Planning
Board and moved FM to the frequencies between 88 and 106 MHz on June 27,
1945. Later the Federal Communications Commission added the frequencies from
106 to 108 MHz which had been given to facsimile transmission but had never
been used for that purpose. This change gave FM radio 100 channels whereas
it only had 40 before, it also added to the number of reserved educational
When in 1945 the Federal Communications Commission moved FM radio to the
higher frequencies, it made all prewar FM radios worthless. The FM interests
said it would cost $75,000,000 to convert and that it would set back the
medium for years, which it did. Of course the FM interests fought back,
Edwin Armstrong began fighting in 1944 to keep the frequencies FM already
had. Armstrong went to court and to Congress, but lost in court and in a
Congress that paid him lip service and little else. In 1945 when the change
was ordered, there were already 55 pioneer FM stations on the air, and no
nonexperimental television stations. The Federal Communications Commission
had its most extensive hearings to that date, September 28 to November 2,
1944, on allocations decisions. When the Federal Communications Commission
was making these decisions it had to balance several factors, but because of
the wartime freeze it had time. The factors were the international
responsibilities of the United States with the International
Telecommunications Union (ITU), the American Armed Forces need for spectrum,
television and FM desiring the same VHF band, and the competing television
systems, color later on UHF and/or black and white now on VHF.
The Federal Communications Commission made several later decisions that
greatly slowed the growth of FM radio:
* the Federal Communications Commission switched the frequencies at which
FM operated, this caused the necessity of all FM equipment to be
reengineered and made all prewar FM receivers obsolete, buyers became
suspicious and weary of buying new FM radios so sales were erratic
* the Federal Communications Commission allowed owners to own AM-FM
combines in the same market, 80% of FM stations were owned by AM
station owners in the same market as an AM station of the owner, this
lessoned the pursuit of FM stations to be successful because that would
hurt AM profits
* duplication and simulcating of programs were permitted by the Federal
Communications Commission. This meant that AM and FM stations would
often if not always play the same programs. Because of this there was
even less reason to buy an FM receiver, and since no one could or would
listen, advertisers wouldn't advertise. Since advertisers did not
advertise the station made no money and little was spent on new
programming, the vicious circle could not be broken for years to come.
In Europe the FM radio broadcast was introduced in Germany after World War
II. In 1948 a new wave-length plan was set up for Europe at a meeting in
Copenhagen. Because of the recent war, Germany (who were not even invited)
were only given a few medium-wave frequencies, which are not very good for
broadcasting. For this reason Germany began broadcasting on USW, "ultra
short wave" (nowadays called VHF). After some amplitude modulation
experience with VHF, it was realized that FM radio was a much better
alternative for VHF radio than AM.
In the 1960s, new technology was added to FM radio to allow FM stereo
transmissions using a mono-compatible stereo multiplexing system.
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.
* Meteor scatter
* Nationwide networks
* Satellite transmission
Internet Radio (1995--)
The term "internet radio" is a misnomer: its consists of putting out
radio-style audio programming over streaming Internet connections: no radio
transmitters need be involved at any point in the process.
* Early technology wars: Push or pull, streaming media or multicast
* Run your own station with http://www.live365.com/ or almost like
Geocities or Hotmail