Television broadcasts are made on different wavebands or groups of channels and your receiving aerial is matched to the appropriate band or group. There are five aerial groups: A, B, C/D, E and W. A television dealer or rental company will advise on which group will serve you best. The size and type of aerial will also affect the quality of signal you receive: if you live close to a main transmitter or relay station, then an aerial with 6-8 elements should work well. If you live at the edge of a transmission coverage area, you may need an aerial with 18 elements in order to pick up a strong signal. Where signal coverage in an area is strong, a low-gain aerial is used, but where it's weaker, a multi-element high-gain aerial strengthens the signal. For people who move home periodically, and take their TV aerial with them, a log-periodic aerial picks up moderate signals if it can be directed at a transmitter.
