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Installation and Technical Manual for the
Limitless™ Multi-Protocol Receiver, WMPR Series
8.6.3 | Outdoor Antenna Installations - Light-
ning Concerns
Outdoor antenna installations can lead to the possible damage
caused by nearby lightning strikes that induce charges or surg-
es on the antenna and/or antenna extension cables.
A lightning arrestor such as the AL6-RSPRSJBW-9 from L-COM
Global Connectivity can be reviewed against application re-
quirements.
, ATTENTION
National, local, and/or regulatory agencies may require the
use of a lightning arrestor and possibly other requirements
for an antenna system installation. It is recommended that
the customer review and adhere to these requirements.
8.6.4 | Lightning Arrestor
The lightning arrestor may be mounted directly on the sensor,
or at the far end of the antenna cable, mounted to a sheet of
metal in a through-hole. Generally, the choice should be made
based on having the shortest, most direct path to a good, solid
ground.
If the lightning arrestor is mounted directly on the sensor, use
caution when attaching a grounding wire to the arrestor to
avoid putting undue stress on the sensor's antenna connector.
If the coax cable is to enter a building, then the lightning arres-
tor should be mounted as close as possible to where the lead-in
wire enters the building. The lightning arrestor recommended
by Honeywell (AL6-RSPRSJBW-9 from L-COM Global Connec-
tivity) features a bulkhead RP-SMA connector with a rubber "O"-
ring seal which can be used for mounting through an enclosure
wall. Both connector ports of the lightning arrestor provide
equal protection no matter which way it is installed. Either port
can face the antenna and either port can face the sensor.
8.6.5 | Site Selection
Before attempting to install your antenna, consider the best
place to install the antenna for safety and performance.
Follow these steps to determine a safe distance from wires,
power lines, and trees.
Step
Action
1
Measure the height of the antenna.
2
Add this length to the length of the tower or mast
and then double this total for the minimum recom-
mended safe distance.
34 sensing.honeywell.com
Generally speaking, the higher the antenna is above the ground,
the better it performs. Good practice is to install your antenna
about 1,5 m to 3 m [5 ft to 10 ft] above the roof line and away
from all power lines and obstructions. If possible, find a mount-
ing place directly above the wireless device so the lead-in cable
can be as direct as possible.
8.6.6 | Antenna Mounting Location with
Respect to Antenna Location
There are several environmental factors to consider with
respect to antenna location during installation. These fac-
tors can affect the radio frequency (RF) signal strength being
both transmitted and received by the Limitless™ switch or
sensor and the Wireless Multi-Protocol Receiver (WMPR). It is
desirable for the antenna to be mounted to limit exposure of
adjacent materials/objects between the Limitless™ switch or
sensor and the WMPR, as they will have an effect on RF signal
strength. If the mounting location for an omni-directional an-
tenna is on the side of a building or tower, the antenna pattern
will be degraded on the building or tower side.
Obstacles that affect antenna patterns and RF signal strength:
•
Indoor: Concrete, wood, drywall, and metal walls, etc.
•
Outdoor: Vehicles, buildings, trees, structures, topolo-
gy, weather conditions, chain link fence, major power
cables, etc.
Rain and moisture: Wireless sensors compliant with IEEE
802.15.4 operate in a 2.4 GHz band. As the peak absorption
frequency of water molecules is approximately 22 GHz, the total
signal attenuation due to rain, fog or moisture is negligable
(less than 0.1 dB/mile for a heavy downpour).
8.7 | Choosing an Antenna Gain (dBi) with
Acceptable Fade-Margin
There are several different Limitless™ Series antenna gain op-
tions to choose from. This section helps determine the antenna
version(s) that will provide suitable RF signal performance for
specific applications.
The Limitless™ Series antenna's actual gain is measured by
how much of the input power from the WMPR's internal radio
is concentrated in a particular direction. The WMPR antenna
transmits RF signals, and also receives RF signals from a Limit-
less™ input. In a particular application, transmit signal strength
may be better than the receive signal strength or vice versa. The
intent is to choose an antenna with the optimum gain relative
to application conditions for both transmitting and receiving.
ISSUE B
32309669
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