Two-way radio

From Free net encyclopedia

A two-way radio is simply a radio that can both transmit and receive (a transceiver). Portable two-way radios are often called walkie-talkies or handi-talkies. Two-way radios are also available in mobile and base configurations. An example of a two-way radio that both transmits and receives at the same time (or full-duplex) is a mobile phone or cellular telephone, which uses two different radio frequencies to carry the two directions of the conversation simultaneously.

Two-way radio frequencies

Two-way radios can operate on many different frequencies, the most common ones being Family Radio Service (FRS) and General Mobile Radio Service (GMRS). The channels that FRS operate on range from 1 to 14 and GMRS channels range from 15 to 22.

The maximum output power for an FRS channel is 0.5 watts, so your range will be limited. The GMRS channels will get you the maximum output power and range on a GMRS two-way radio, which is a maximum of 50 watts. GMRS users can also use the first 7 channels of FRS, but the power limit for these channels is 5 watts. The FCC requires consumers to purchase a license if they will be using a GMRS channel.

Another form of 2-way radio service is Multi-Use Radio Service (MURS). MURS uses 5 channels on the VHF band, 2 of which are shared with the business band radio service (more on this below). MURS, like FRS, does not require a license to use, and has a maximum power limit of 2 watts TPO (Transmitter Power Output), 4 times the power limit of FRS radios.

The business band radio service uses the same VHF frequency ranges as MURS, and the same UHF frequency ranges as GMRS & FRS. Business band radio service also requires a license to use, like GMRS, and has several frequencies specifically assigned to it (usually designated as "color dot" frequencies, such as "red dot" (151.625 mHz)). As its name suggests, it is used by business and other commercial interests.