4101-2 Controller Installation Handbook
15-2
is installed does not have too much background RF noise and the
doors/doorframes are not made of metal. For these reasons it is
essential to carry out a site survey before specifying door loops - in a
particularly noisy site they may not work at all!
The side loop can be a few turns of a single wire, or can have
separate transmit and receive antennas, acting like a much larger
280 Reading Head. It is less susceptible to noise than the simple door
loop, but is still more susceptible than the 280 Reading Head.
The AVI loop is a special configuration designed for use with vehicles
and the 970 Vehicle Tag.
In reasonably noise-free conditions, a loop antenna should give a
reliable reading range of at least 1.2 metres, and can give much
more.
To Next Page