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The Q-code is a standardised collection of three-letter codes that each start with the letter "Q". It is an operating signal initially developed for commercial radiotelegraph communication and later adopted by other radio services, especially amateur radio.
The Maidenhead Locator System (a.k.a. QTH Locator and IARU Locator) is a geocode system used by amateur radio operators to succinctly describe their geographic coordinates, which replaced the deprecated QRA locator, which was limited to European contacts. [1]
The QRA locator, also called QTH locator in some publications, is an obsolete geographic coordinate system used by amateur radio operators in Europe before the introduction of the Maidenhead Locator System. As a radio transmitter or receiver location system the QRA locator is considered defunct, but may be found in many older documents.
The QSK code is one of the earliest signal reporting formats and is a part of the Q code used for commercial radiotelegraph communication, appearing as one of the twelve Q Codes listed in the 1912 International Radiotelegraph Convention Regulations, and was later adopted by other radio services, especially amateur radio.
Radio communications, prior to the advent of landlines and satellites as communication paths and relays, was always subject to unpredictable fade outs caused by weather conditions, practical limits on available emission power at the transmitter, radio frequency of the transmission, type of emission, type of transmitting antenna, signal waveform characteristics, modulation scheme in use ...
An amateur radio license is valid only in the country where it is issued or in another country that has a reciprocal licensing agreement with the issuing country. [42] [43] In some countries, an amateur radio license is necessary in order to purchase or possess amateur radio equipment. [44]
Morse code is called the original digital mode. Radio telegraphy, designed for machine-to-machine communication is the direct on / off keying of a continuous wave carrier by Morse code symbols, often called amplitude-shift keying or ASK, may be considered to be an amplitude modulated mode of communications, and is rightfully considered the first digital data mode.
QSK operation is a technical challenge: It requires very fast T/R RF switches at the high power and voltage side of the radio transceiver. Such switches must be controlled automatically by the telegraph key, and as such they must be rapid enough to be perceptually undetectable by the telegraph operator.