map produced by Motorola

This map was prepared for an educational session at the 2000 annual conference of the Association of Public-Safety Communications Officials (APCO) in Boston during a session on the 24 MHz allocation of spectrum to public safety in the 700 MHz band. It demonstrates that certain areas of the country may have delayed access to the allocation because UHF television stations are icensed on an adjacent or co-channel. These stations are due to migrate to digital television (DTV) by 2006--but only if certain consumer acceptance levels are met.

As you can see, there is major blockage in the Los Angeles and San Francisco areas; a corridor running from Indiana-Ohio south to Atlanta; and the entire eastern coast north of North Carolina.

The coverage areas were made assuming the highest permissable output power (500 watts base, 25 watts mobile) and tallest permissible antenna height (500 feet height above average terrain [HAAT]).

The 24 MHz allocation is split into two parts--12 MHz from channels 63 and 64, and 12 MHz from channels 68 and 69. Radio systems using the 700 MHz radio frequencies must use trunked technology, which puts the base and mobile frequencies 30 MHz apart--one from 63-64 and the other from 68-69.

Therefore, if any of the four TV channels is occupied by a UHF-TV station--and therefore blocking public safety from using that channel---any allocations on the corresponding UHF-TV channel pair are also blocked. These are indicated by the red circles.

Similarly, if a UHF-TV station occupies a TV channel adjacent to frequencies potentially used by public safety, frequencies on that adjacent TV channel would be blocked by interference rules. These channels are indicated by the blue circles.

See the map for channel 63 and 68 blockages.