Nancy O’Neal, age 13, of Helena, Mont., for her question:
HOW FAR WILL A CB RADIO TRANSMIT?
CB radio is a method of short distance communication used by private citizens. It is actually called citizen band radio (CB) and it operates on a group of radio frequencies that many nations reserve strictly for private use.
Most CB sets are called transceivers, which consist of a transmitter and a receiver. Most CB transmitters broadcast for distances of fewer than five miles in cities and up to 20 miles in rural areas.
Actually, the broadcast range of CB sets varies with the atmospheric conditions, the terrain, the design and height of the set’s antenna and the amount of power supplied to the transmitter,
Government regulations in the United States and Canada limit the power of a CB transmitter to a maximum of four watts. In the United States and Canada, the governments also require a CB transmitter of more than one tenth watt to be licensed.
A United States citizen 18 years old or older may obtain a CB license from the Federal Communications Commission, Gettysburg, Pa. 17325. A Canadian may obtain a General Radio Service license from the nearest district office of the Department of Communications.
In the United States, CB radio has 23 channels, with frequencies of 26.965 to 27.255 megahertz. The Canadian CB, called General Radio Service, has 22 channels. They have frequencies of 26.97 to 27.27 megahertz.
CB radio is most frequently used for conversations between places that are not linked by telephone. Many motorists and truck drivers use it to talk with other highway travelers or with people who are in offices or homes.
Although most units consist of both a transmitter and a receiver, some CB devices receive radio signals but do not transmit them.
Walkie talkies used privately also operate on the citizen band. A walkie talkie is a portable two way radio that provides quick communications. The system is used by policemen, soldiers, sportsmen and many workmen.
Most walkie talkies operate with a power of less than one tenth watt. They can send and receive messages over distances up to one mile. Larger units, using from one to five watts of power, can send and receive messages over maximum distances of two to four miles.
Sometimes CB radio and walkie talkie signals can travel over hundreds of miles from the source. This happens when the signal skips or is reflected off the ionosphere. Electrical devices operating nearby, and such obstacles as buildings, may cut down on a CB or walkie talkie’s effective range.
Remote controls for such devices as model airplanes and automatic garage door openers also operate on CB radio frequencies.