Television & Radio Hardware - Multiplexing Signals
As with television installs, some people also want an aerial to allow them to receive FM and DAB signals. Many houses also have satellite installations as well. This could potentially mean four cables running from the aerials/dish to a single area where the equipment sits. Multiplexing is an alternative which allows just a single cable to be used.
How It Works
The cable for each aerial runs to a multiplexer (more usually known as a diplexer/triplexer depending on the number of inputs). This has an output which the downlead is connected to, which runs to a surface plate where the devices will be connected. At the surface plate (which must match the multiplexer), the signals are split back out to go to each device.
As with other splitters, amplifiers, and boosters, the diplexer/triplexer should be installed close to the aerial. This can either be in the loft or other space, or by way of a mast head type.
The mast head variant is best suited to poles which have mutiple aerials attached such as television, FM and DAB. Although, satellite signals can also be multiplexed, they do not tend to be installed to the same pole as other aerials (although they can be).