Overlapping Footprints And Black Spots - Bosch Integrus Operation Manual

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4.2.6

Overlapping footprints and black spots

When the footprints of two radiators partly overlap, the total coverage area can be larger than
the sum of the two separate footprints. In the overlap area the signal radiation power of two
radiators are added, which increases the area where the radiation intensity is larger than the
required intensity. However, differences in the delays of the signals picked up by the receiver
from two or more radiators can result in that the signals cancel each other out (multi path
effect). In worst-case situations this can lead to a loss of reception at such positions (black
spots).
The next two figures illustrate the effect of overlapping footprints and differences in signal
delays.
Figure 4.17: Increased coverage area caused by added radiation power
Figure 4.18: Reduced coverage area caused by differences in cable signal delay
The lower the carrier frequency, the less susceptible the receiver is for differences in signal
delays. The signal delays can be compensated by using the delay compensation switches on
the radiators (see section Determine the radiator delay switch positions, page 60).
Bosch Security Systems B.V. Operation manual
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