Walkie-talkie
From Academic Kids
Recreational_Walkie_Talkies.jpg
A walkie-talkie is a portable, bi-directional radio transceiver, first developed for military use. Major characteristics include a half-duplex (only one of receive or transmit at a time) channel and a push-to-talk switch that starts transmission. The typical physical format looks like a telephone handset, possibly slightly larger but still a single unit, with an antenna sticking out of the top.
Talkiewalkie.jpg
Hand-held transceivers became valuable communication tools for police, emergency services, and industrial and commercial users, using frequencies assigned for these services.
Low-power versions, exempt from licence requirements, are also popular children's toys. Prior to the change of CB radio from licensed to un-licensed status, the typical toy walkie-talkie available in retail stores in North America was limited to 100 milliwatts of power on transmit and the 27 MHz citizens' band channels. Other toy walkie-talkies operate in the 49 MHZ band shared with cordless phones and baby monitors; typically these devices are very crude electronically and may lack even a volume control, though they may have elaborate packaging.
The first radio receiver/transmitter to be nick-named walkie-talkie was the Motorola SCR-300 invented by Henryk Magnuski in 1940. Motorola also produced the SCR-536 radio during the war, and it was called the "Handie-Talkie" (HT). Al Gross also worked on the early technology behind the walkie-talkie between 1934 and 1941, and is sometimes said to actually have invented it.
The personal walkie-talkie has now become popular again with the Family Radio Service. FRS operates in the GMRS band, which is also used for business walkie-talkies and mobile radios. While FRS walkie-talkies are popular toys, they are also a useful communication tool for business and personal use.
External links
- Picture of a SCR-536 Handie-Talkie (http://www.plusgsm.pl/magazyn/99_25/images/zdj4c.jpg)
- SCR-300-A Technical Manual (http://www.scr300.org/)
