Stacking bistatic microwaves
a - 10 • • • MPS-4100 product guide
Figure a-10 and Figure a-11 plot the calculated antenna height versus the
separation distance relationship for constructive phasing for X-Band (MPS-4100,
Microwave Series 14000, and Series 16000) and for K-Band (Microwave Series
24000) respectively. The calculation assumes that the two antennas (transmit and
receive) are mounted at the same height above a relatively flat surface. The areas
of constructive phasing are located on each nodal line, (i.e., N1, N2, N3, etc.) and
below N1.
The following procedure and recommended mounting height table provide a
starting point for determining the mounting height for your specific application.
Many factors must be taken into account to ensure optimum performance.
Therefore, some adjustments to the recommended mounting heights will most
likely be required.
Mounting height procedure
1. Determine the unit separation in accordance with the detection requirements
and clearances (see the MPS-4100 Application Note #1 -
DO’s and DON’Ts: a
planning primer
).
2. For the lower pair, select the mounting height of the center of the antenna
from the Recommended mounting heights table. Adjust the height to ensure
that the operating point is below N1 (see Figure a-10 or Figure a-11).
3. For an installation where both X-Band and K-Band microwave units are being
employed, the K-Band (Microwave Series 24000) unit MUST be the lower
unit.
K-Band microwave sensors have better sensitivity to slow-moving intruders.
However, they are more susceptible to nuisance alarms from rain and snow.
The closely spaced nodal lines (see Figure a-11) for K-Band microwaves
means that if the K-Band unit is used as the upper unit, it will be very difficult
to ensure constructive phasing under all weather conditions.
4. For the upper units, select the mounting height of the center of the antenna
from the Recommended mounting heights table. Adjust the height to ensure
that the operating point is on a nodal line, and that the received signal
strength is at the maximum possible.
5. Ensure that both the transmitter and the receiver of each pair are mounted at
the same height.
6. Perform all site maintenance as required.
Ensure that the operating point (mounting height versus
separation) is on a constructive nodal line, or below N1 (see
Lower unit
Mounting height
Upper unit
Mounting height
MPS-4100
76 cm (30 in.)
MPS-4100
150 cm (60 in.)
Series 14000
60 cm (24 in.)
MPS-4100
136 cm (54 in.)
Series 16000
60 cm (24 in.)
Series 16000
120 cm (48 in.)
Series 24000
30 cm (12 in.)
Series 16000
90 cm (36 in.)
Recommended mounting heights
Содержание MPS-4100
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