A relay league is a chain of message forwarding stations in a system of

optical telegraph An optical telegraph is a line of stations, typically towers, for the purpose of conveying textual information by means of visual signals. There are two main types of such systems; the semaphore telegraph which uses pivoted indicator arms and ...

radio telegraph Wireless telegraphy or radiotelegraphy is transmission of text messages by radio waves, analogous to electrical telegraphy using electrical cable, cables. Before about 1910, the term ''wireless telegraphy'' was also used for other experimental t ...

stations, or riding

courier A courier is a person or organisation that delivers a message, package or letter from one place or person to another place or person. Typically, a courier provides their courier service on a commercial contract basis; however, some couriers are ...

s. Early 19th century methods of this type evolved into the

electrical telegraph Electrical telegraphs were point-to-point text messaging systems, primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems ...

networks of the mid-to-late 19th century.

Radio relay leagues

Radio amateur An amateur radio operator is someone who uses equipment at an amateur radio station to engage in two-way personal communications with other amateur operators on radio frequencies assigned to the amateur radio service. Amateur radio operators h ...

s have been early in arranging relay leagues, as is reflected in the name of the organization of

American Radio Relay League The American Radio Relay League (ARRL) is the largest membership association of amateur radio enthusiasts in the United States. ARRL is a non-profit organization, and was co-founded on April 6, 1914, by Hiram Percy Maxim and Clarence D. Tuska of ...

(ARRL). Radio amateur message relay operations were originally conducted in the first two decades of the 20th century using

Morse code Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of ...

via

spark-gap transmitter A spark-gap transmitter is an obsolete type of radio transmitter which generates radio waves by means of an electric spark."Radio Transmitters, Early" in Spark-gap transmitters were the first type of radio transmitter, and were the main type use ...

s. As

vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...

s became affordable, operations shifted to more efficient manual telegraphy transmitters, referred to as ''CW'' (

Continuous wave A continuous wave or continuous waveform (CW) is an electromagnetic wave of constant amplitude and frequency, typically a sine wave, that for mathematical analysis is considered to be of infinite duration. It may refer to e.g. a laser or particle ...

). Messages were relayed station-to-station, typically involving four or more re-transmission cycles to cover the continental

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, in an organized system of amateur radio networks. After

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

, voice and

radioteletype Radioteletype (RTTY) is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations connected by radio rather than a wired link. Radioteletype evolved from earlier landline teleprinter o ...

implementations of the message relay system were employed.

References

{{DEFAULTSORT:Relay League History of telecommunications Telegraphy

Radio relay leagues

See also

References