Walkie-Talkies
A Walkie-Talkie is a portable two-way radio transceiver. A transceiver is a device that has a transmitter and a receiver which are combined together to share common circuitry. A Walkie-Talkie is a handheld communication device and it includes a half-duplex channel i.e. it supports communication in both directions but only one person can transmit at a given instant. However, any number of people can receive the transmitted message. A Walkie-Talkie also feature a push-to-talk switch which is used to switch to the transmit mode from the reception mode.
A Walkie-Talkie has an antenna coming out from the top and it resembles a telephone handset. Some Walkie-Walkies come with advanced capabilities such as trunking capabilities, voice scrambling capabilities and even advanced squelch capabilities. It is also possible to attach speakers and external microphones to some walkie-talkie models and some models even support hands-free operation because of the VOX capability. The communication range is short as the output power is limited to few watts and so, repeaters are used for reliable communication. A repeater listens on one frequency and it then retransmits the message on another frequency. The repeaters are located at different points within the desired area so as to support reliable communication.
Some low-power Walkie-Talkies that operate in 49 Hz band are also available and these are generally used as toys for children. Walkie-Talkies with 'code key' are used to transmit Morse code to other Walkie-Talkies on the same frequency. A Morse code is basically an encoding scheme which uses short and long elements to represent punctuation, numerals, special characters and letters. It is used for transmitting telegraphic information.
Apart from commercial and amateur Walkie-Talkies, personal Walkie-Talkies are also available which are designed to work in the UHF. Some personal Walkie-Talkies have the ability to send pictures and text messages to similar devices and some personal Walkie-Talkies also include receivers for the FM and the AM broadcast radio. These personal Walkie-Talkies are designed to work in the 27 MHz area. Personal Walkie-Talkies are usually used by people to stay in touch when they're at an over crowded place.
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