- Amateur radio mobile operation
Amateur radio mobile operation refers to the use of
amateur radio equipment from a moving vehicle. An amateur radiotransceiver designed specifically for use in vehicles is usually mounted with the microphone and control panel in reach of the driver. In theUnited States , such a device is typically run off of the host vehicle's 12volt direct current electrical system.Mobile radio s for amateur radio can be home-made by amateur radio enthusiasts, or may be purchased from an amateur radio equipment supplier and immediately used out-of-box. In the US, some amateurs modify commercial two-way radios and use them on amateur radio frequencies. Each installation would also have a vehicle-mounted antenna connected to the transceiver by acoaxial cable . Some models may have an external, separate speaker which can be positioned and oriented facing the driver to overcome ambient road noise present when driving.History
Amateur radio operators were pioneers and experimenters who developed the first mobile radio equipment. Early mobile radios operated on HF bands. Some were
amplitude modulation phone (voice) radios and some used CW to sendMorse code messages when parked. Because ofwavelength s in the 15- meter to 80-meter range, HF antennas were large and the antenna patterns were affected by the host vehicle's steel body. Electrical traits of antennas were modified so they would not have to be a full quarter wavelength long.Vaccuum tube radio designs useddynamotor s, a twelve volt motor that turned aelectrical generator to makehigh voltage direct current electricity. Some early mobile rigs were the size of a suitcase.Later technology evolved to use vibrators and
solid-state power supplies in order to make high voltage for the vacuum tubes. These circuits includedinverter s which changed the 12V DC to AC which could be passed through a transformer to make high voltage. The high voltage side of the transformer was rectified to make DC for the vacuum tubes. A common trait of vacuum tube type mobile rigs was their heavy weight; this was partly caused by including iron-coretransformer s in the power supplies. High voltage power supplies were inefficient and vacuum tube filaments added tocurrent demands, taxing vehicle electrical systems.Amateur radio operators expanded the technology to work on frequency bands into UHF. Solid state equipment arrived in the 1960s, with more efficient circuitry and smaller size. By the mid 1970s, vacuum tube-type power
amplifier s had been replaced with high-powertransistor s. Amateur radio operators pioneeredtelephone connectivity andpacket radio data communication from automobiles.Mobile radios
Modern equipment is
microprocessor controlled, operates on multiple frequency bands, and has built-in options such as cross-band repeat. Mobile vehicular or ship-based systems exist today including amateur radio systems inbicycle s,truck s,van s,car s,boat s, ormotorcycle s.Mobile antennas
See also
*
Mobile radio External links
* [http://users.rio.com/kg7fu/mobile.html Mobileering Information Page]
* [http://www.qsl.net/ka6wke/hfmobile.html KA6WKE's HF Mobile Web Pages]
* [http://www.qsl.net/k4mg/Radios/FT-100/FT-100.htm HF Mobile Rig - FT-100]
* [http://service.gm.com/techlineinfo/radio.html A typical installation guide for a mobile radio/telephone (General Motors Corporation)]
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