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The first police radio systems were implemented in Detroit in 1928, when the Detroit Police Department set up a one-way radio system to broadcast crime information to police cars. [2] The frequency was assigned the call sign "KOP" by the Federal Communications Commission .
A radio band is a small frequency band (a contiguous section of the range of the radio spectrum) in which channels are usually used or set aside for the same purpose. To prevent interference and allow for efficient use of the radio spectrum, similar services are allocated in bands.
NATO LETTER BAND DESIGNATION [citation needed] BROADCASTING BAND DESIGNATION [citation needed] NEW [when?] NOMENCLATURE: OLD [when?] NOMENCLATURE: BAND: FREQUENCY : BAND: FREQUENCY (MHz) A: 0 – 250 I: 100 – 150 Band I 47 – 68 MHz (TV) Band II 87.5 – 108 MHz (FM) G: 150 – 225 Band III 174 – 230 MHz (TV) B: 250 – 500 P: 225 – 390 ...
The frequencies used are within the 70-centimeter band, which is currently otherwise reserved for government and amateur radio operations in the United States and most nations worldwide. LPD hand-held radios are authorized for licence-free voice communications use in most of Europe using analog frequency modulation (FM) as part of short range ...
The International Telecommunication Union defines frequency allocation as being of "a given frequency band for the purpose of its use by one or more terrestrial or space radiocommunication services or the radio astronomy service under specified conditions". [2] Frequency allocation is also a special term, used in national frequency ...
This is the navigation box for the International Amateur Radio Bands. All bands in this template are either mentioned in the International Telecommunication Union 's "Table of Frequency Allocations" or the table's footnotes, with the exception of allocations listed in italics .
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Shortwave bands are frequency allocations for use within the shortwave radio spectrum (the upper medium frequency [MF] band and all of the high frequency [HF] band). Radio waves in these frequency ranges can be used for very long distance (transcontinental) communication because they can reflect off layers of charged particles in the ionosphere and return to Earth beyond the horizon, a ...