Traditional terrestrial TV broadcast uses a series of overlapping transmitters each using a different frequency to avoid mutual interference. Enough TV channels are allocated to the system to limit channel reuse to transmitters that are very different from each other.
This kind of broadcast system uses a large amount of radio spectrum. The system also provides marginal performance where TV receivers shaded by terrain or tall buildings.
In hilly terrain and areas subject to strong multipath, reception can be improved if overlapping transmitters use time coordination. Each transmitter sends the same signal on the same frequency at the same time. The tight time synchronization is derived from GPS signals using specialized timing receivers.
This technical approach to broadcasting conserves radio frequency channels and improves reception in marginal overlap areas between transmitters. Benefits can be applied to TV, Radio and most digital transmission systems.
Land Mobile Radio (LMR) systems traditionally use a range of different frequencies in overlapping areas. The benefits of a single frequency network can be applied for the transmission from the dispatcher to the person in the field but not for the reverse direction. LMR networks organized this way are known as simulcast or semi-synchronous and require precise time and frequency coordination. Trimble timing receivers are a perfect match for these applications.