Demand for cellular telephones has grown rapidly since their introduction four years ago--the number of cellular users nationally has now surpassed the 1-million mark. There are now two companies serving Southern California--PacTel Cellular and Los Angeles Cellular. PacTel's system, covering Los Angeles, Orange, Riverside, San Bernardino and Ventura counties, is the nation's largest in terms of the number of cell sites, covering more than 9,200 square miles. Together, the companies serve 110,000 users.
Here is how the mobile cellular phones work:
Cellular phones are powered by the car battery or portable battery pack.
The PacTel network uses radio frequencies in the 800-megahertz range of the UHF band set aside by the FCC for cellular use. The instant you turn on the ignition, your cellular phone, in its cradle, begins repeatedly scanning all the channels--even if you are not using your phone. In this manner, you may receive incoming calls.
Cellular technology works by dividing a city into smaller geographic areas called cells, each served by one or more radio transmitters. These are low-powered base stations, consisting of a radio transceiver and a bank of computerized equipment, with antennas atop communication towers of various heights.
Such cell sites are designed to accommodate thousands of callers because the same radio frequency can be used simultaneously throughout the system. There are about 45 channels assigned to every cell site, although there may be more or less depending on demand in any given area.