MANY people in rural Ireland receive their TV multi channel service via a deflector system, a simple piece of technology that can deliver a range of channels, if they are transmitted close by.
A typical system would work with aerials on high ground picking up a weak signal from BBC1, BBC2, UTV and Channel 4 transmitted in Northern Ireland.
When that signal has been picked up, probably by a "quad" or four aerials pointing towards the North, it is converted to an other frequency to cut out feedback or a howling effect. Typically it will be changed from, say, channel 21 on the spectrum to 56.
It is then amplified and transmitted. Sometimes the transmitter can be as weak as 10 watts, if it is being sent down a valley for instance.
Houses can then simply pick up the signal on ordinary UHF aerials. The signal is free and can be picked up by anyone, thus deflector systems tend to be community initiatives rather than commercial operations.
Deflector systems do not, of course, pay any royalties to the companies whose signal they take.
The signal can be sent from one system to another, so that when the signal from a deflector is getting weak, 20 or 30 miles from the transmitter, another system can pick it up, amplify it and send it out again.
Typically a system consists of the aerials, a small building housing equipment, access to the ESB power supply and possibly a backup generator.