Senstar Corporation 24000 Manuel D’Utilisation
page 2
E6DA0209-001, Rev B
5.
For multiple zone configurations, carefully plan
the layout, ensuring that there are no possible
conflicts or interference in modulation frequency
or polarization.
the layout, ensuring that there are no possible
conflicts or interference in modulation frequency
or polarization.
6.
Use a minimum 10 cm (4 in.) post to ensure
stability. Each post must be installed in a concrete
base that is at least 61 cm (24 in.) in diameter and
either 91 cm (36 in.) deep, OR, 15 cm (6 in.) below
the frost line, whichever is greater.
stability. Each post must be installed in a concrete
base that is at least 61 cm (24 in.) in diameter and
either 91 cm (36 in.) deep, OR, 15 cm (6 in.) below
the frost line, whichever is greater.
Determining the mounting height
The received signal is the vector sum of the direct signal
and the reflected signals. The quiescent (no intruder)
received signal is greatly influenced by the mid-point
reflections. The phase relationship between the direct
and reflected signals will slowly change as the sensor
antennas are raised from the ground level.
and the reflected signals. The quiescent (no intruder)
received signal is greatly influenced by the mid-point
reflections. The phase relationship between the direct
and reflected signals will slowly change as the sensor
antennas are raised from the ground level.
The two signals (direct and reflected) will combine
constructively (in phase), or destructively (out of phase),
depending on the sensor mounting height and
separation distance. Constructive phasing is preferable
because of the higher net signal level received.
Destructive phasing should be avoided because the low
signal level causes the receiver’s automatic gain control
(AGC) to operate closer to the top of its range. This will
result in a higher nuisance alarm rate when the
microwave path loss increases, for example, during rain
or snow.
constructively (in phase), or destructively (out of phase),
depending on the sensor mounting height and
separation distance. Constructive phasing is preferable
because of the higher net signal level received.
Destructive phasing should be avoided because the low
signal level causes the receiver’s automatic gain control
(AGC) to operate closer to the top of its range. This will
result in a higher nuisance alarm rate when the
microwave path loss increases, for example, during rain
or snow.
Charts 1 and 2 on page plot the calculated antenna
height versus the separation distance relationship for
constructive phasing for X-Band (Intelli-WAVE,
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.
height versus the separation distance relationship for
constructive phasing for X-Band (Intelli-WAVE,
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.
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
Intelli-WAVE Application Note #1 - DO’s and
DON’Ts: a planning primer).
the detection requirements and clearances (see the
Intelli-WAVE 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 Table 1,
Recommended mounting heights. Adjust the
height to ensure that the operating point is below
N1 (see Chart 1 or 2).
the center of the antenna from Table 1,
Recommended mounting heights. Adjust the
height to ensure that the operating point is below
N1 (see Chart 1 or 2).
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 (Chart 2) 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.
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 (Chart 2) 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 Table 1,
Recommended mounting heights. 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.
the center of the antenna from Table 1,
Recommended mounting heights. 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.
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 Charts 1 and 2 on the next page).
below N1 (see Charts 1 and 2 on the next page).
Table 1 Recommended mounting heights*
Lower unit Mounting height Upper unit Mounting height
Intelli-WAVE 76 cm (30 in.)
Intelli-WAVE 76 cm (30 in.)
Intelli-WAVE 150 cm (60 in.)
Series 14000 60 cm (24 in.)
Intelli-WAVE 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.)