Antenna Tuning Unit (ATU) Installation
Introduction
Each access control point (e.g. door, roadway, etc.) has at least two
antennas:
•
A Low Frequency (LF) loop antenna that broadcasts a
wakeup
signal at 132 kHz to any Tags that may be within the antenna
field of radiation.
•
A dipole antenna designed for the Ultra-High Frequency (UHF)
range for receiving a response signal (315 MHz) from each Tag.
For road-loop sites, the two antennas are separate to accommodate
unique installation and distance requirements.
For interior installations, the two antennas are packaged in a single
housing that can be inconspicuously mounted near the access
monitoring point.
An ATU optimizes the performance of one antenna pair to its
environment.
Installation Considerations
When selecting a location for each ATU, keep in mind that it should
be mounted:
•
within
20 feet
cable length of its antennas
•
within
80 feet
cable length of the Reader
Review the appropriate antenna section in this manual prior to
installing each ATU. The ATU should be mounted in a location that
provides protection from the elements and easy access for cabling
and system tuning.
IMPORTANT!
Place the ATU in a waterproof box if it is mounted
outside.
In some installations, it may be desirable to install the ATU out of
sight (e.g. above ceiling tiles).