Channel 5 has a smaller network of transmitters. Only a limited number of frequency channels are available for the transmission of UK television services. Analogue transmissions use these 8 MHz wide frequency channels to provide a single service but the ITC has found a way of inserting up to six services in the same space. Known as multiplexes, six of these channels can, using digital techniques, be interleaved between the analogue channels. They are broadcast from 80 transmission sites, where the first four multiplexes reach about 80 per cent of the population, and the remaining two some 75 per cent.
Digital transmissions are much less liable to interference such as ghosting and electrical noise.
Although at a much lower power than analogue transmission the services can be received on existing aerials and portable reception is possible.