Westermo RM-505U-K - Manual (Page 22)

505K Radio Telemetry Module User Manual
    ELPRO Technologies Pty Ltd 2008 Page 22
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.
3.2.3 Collinear antenna.
A collinear antenna may be used in the same way as a 3 element Yagi to compensate for the
losses in long lengths of coaxial cable. This type of antenna is generally used at a central site
with more than one remote site or at a repeater site. The collinear antenna looks similar to the
dipole, except that it is longer.
3.3 Connection Plug
External power and input signals are connected using a 7-pin weatherproof plug, provided
with the module. The plug needs to be assembled as per the following diagram.
505U
Antenna installed
with drain holes
down
Coax feed looped
at connection
90 o
Coaxial surge
diverter