Most aerials used are of the Yagi type consisting of a main boom with several straight rods across it. The more rods (elements), the higher the gain and the sharper the aerial directivity becomes. In areas with a strong signal a Yagi with between 10 and 18 elements will generally give good results. For areas with weaker signals a high-gain aerial with mast-head amplifier (booster) may be required.
The receiving aerial must match the channel group used by the transmitter serving the local area, point towards the transmitter, and be in the same ‘plane of the polarisation’. The commonly used ‘Yagi’ aerial should be mounted with the rods horizontal to suit horizontally polarised transmissions (all main transmitters) and vertical to suit vertically polarised transmissions (most relay transmitters).
| Channels | Aerial Group | Colour Code |
|---|---|---|
| 21-37 | A | Red |
| 35-53 | B | Yellow |
| 48-68 | C/D | Green |
| 35-68 | E | Brown |
| 21-48 | K | Grey |
| 21-68 | W | Black |
Local Channel Groups, Aerial Transmitter Selection and Polarisation.
Transmission Frequencies and Polorisation
provides details about local transmission frequencies for digital broadcasts.