Page "Advanced Mobile Phone System" Paragraph 11

The anatomy of each channel is composed of 2 frequencies.

416 of these are in the 824 – 849 MHz range for transmissions from mobile stations to the base stations, paired with 416 frequencies in the 869 – 894 MHz range for transmissions from base stations to the mobile stations.

Each cell site will use a subset of these channels, and must use a different set than neighboring cells to avoid interference.

This significantly reduced the number of channels available at each site in real-world systems.

Each AMPS channel has a one way bandwidth of 30 kHz, for a total of 60 kHz for each duplex channel.