Chapter Three
Installation
MAN_105G_1.5
Page
24
Dipole antennas should be mounted vertically, at least 1 metre away from a wall or mast for
maximum performance.
3.2.2
Yagi antenna.
Yagi antennas are directional. That is, they have positive gain to the front of the antenna,
but negative gain in other directions. This may be used to compensate for coaxial cable loss
for installations with marginal radio path.
Yagi antennas should be installed with the central beam horizontal and must be pointed
exactly in the direction of transmission to benefit from the gain of the antenna. Also note that
Yagi antennas normally have a drain hole on the folded element - the drain hole should be
located on the bottom of the installed antenna.
The Yagi antennas may be installed with the elements in a vertical plane (vertically
polarised) or in a horizontal plane (horizontally polarised). For a two station installation,
with both modules using Yagi antennas, horizontal polarisation is recommended. If there are
more than two stations transmitting to a common station, then the Yagi antennas should have
vertical polarisation, and the common (or “central” station should have a dipole or collinear
(non-directional) antenna.