Mad Max
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| Wireless Communications : Handheld Radio Transceivers |
| Written by madmax | |
| Thursday, 12 August 2010 20:03 | |
 Police, fire, and other emergency organizations, as well as the military, have used two-way wireless radio communication since the 1930s. Early vehicle-based radios were large, heavy units. After the invention of the transistor in 1948, radios shrank in size to small handheld radio transceivers. Public two-way radios with several frequency options are widely available as well. Usually limited in range to a few miles, these units are great aids for such mobile professionals as construction workers, film crews, event planners, and security personnel. Simpler two-way radios, called walkie-talkies, have been popular children’s toys for years. Most walkie-talkies broadcast on channel 14 of the citizens band (CB), a range of frequencies grouped into channels and allocated for public use. CB radios can transmit and receive on 40 different channels. An unlicensed radio service, the Family Radio Service, allows individuals to use high-frequency wireless devices with a range of up to 3.2 km (2 mi). |
