Microwave barrier
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SELECTING THE INSTALLATION LOCATION
Attention! The safety and reliability of the operation of the detector depend on the strict
observation of the following requirements.
The presence of water due to overflow/spillage/leakage/seepage/etc. from nearby structures (e.g.,
roofs, etc.) should be avoided in the direct vicinity of the detector units (in the direction of the
emission, no closer than 16.40 ft. (5 m); perpendicularly to the direction of the emission, no closer
than 0.82 ft. (0.25 m)).
The preparation and maintenance of an exclusion zone, where the presence of bushes and
branches of trees, as well as of big, immovable objects (e.g., buildings, etc.) – see
Comment
below
– is not allowed, is necessary. The presence or motion of other movable objects (tractors, people,
animals, etc.) is also not permitted in the exclusion zone. The recommended width of the exclusion
zone for various detector segment lengths is shown below.
The horizontal distance from the detection zone axis to the edge of the exclusion zone must
be:
-
at least 3.94 ft. (1.2 m) for a segment with a length of up to 164 ft.
(50 m);
-
at least 4.92 ft. (1.5 m) for a segment with a length of from 165-328 ft.
(51-100 m);
-
at least 6.56 ft. (2.0 m) for a segment with a length of from 329-656 ft.
(101-200 m);
-
at least 8.20 ft. (2.5 m) for a segment with a length of from 657-984 ft.
(201-300 m).
In the exclusion zone, optimally the maximum height variation between bare ground and
that with snow or long grass cover should not exceed 1 ft. (0.3 m). Note – modified
effective use of the detector is still possible in conditions of greater height variation, e.g., in
situations where it is conceivable that an intruder might attempt to evade detection by
using higher areas of the snow cover itself for concealment of approach. In such cases, it
may be necessary to alter the generally recommended height of installation of the detector
units; however, the
Note
below should always be given due consideration.
Comment
– Within the exclusion zone, there should be absolutely no presence of non-radio
transparent (e.g., stone, metal, ferroconcrete, etc.) natural or man-made objects like
boulders, walls, barriers or other large stationary entities which might conceivably produce
signal disturbances such as noise or reflection.
The presence of nearby walkways, bikeways, roadways, railways, etc., forested tracts, and large,
immovable objects and structures must be at a distance from the detector of no less than twice
the width of the exclusion zone itself. In the event of subjection of the detector or immediately
adjacent objects to vibration caused by passing traffic, the appropriate distance of the detector
therefrom must be determined by trial-and-error.
