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TXP-WTA_Instruction_Manual_(Rev1.3)
10.1.3 Mounting Near Other Antennas
NOTE: Avoid mounting your network's antenna near any other antenna even when the other antenna is transmitting
on a different radio band. High RF energy of the transmission from a close antenna can deafen a receiver. This is a
common cause of problems with wireless systems.
Because antennas are designed to transmit parallel to the ground rather than up or down, vertical separation
between antennas is a lot more effective than horizontal separation. If mounting near another antenna cannot be
avoided, mounting it beneath or above the other antenna is better than mounting beside it.
Using different polarity to the other antenna (if possible) will also help to isolate the RF coupling.
10.1.4 Coax Cables
If a coax cable connects to the antenna via connectors, it is very important to weatherproof the connection using
sealing tape. Moisture ingress into a coax cable connection is the most common cause of problems with antenna
installations.
A three-layer sealing process is recommended:
1. Add an initial layer of electrical PVC tape.
2. Add a second layer of self-vulcanizing weatherproofing tape.
3. Add a final layer of electrical PVC tape.
Allowing a drip "U loop" of cable before the connection allows:
•
Water to drip off the bottom of the U instead of into the connection
•
Reduces installation strain
•
Provides spare cable length in case later the original connectors need to be removed (the cable can be cut
back, and new connectors fitted)
Avoid installing coax cables together in long parallel paths. Leakage from one cable to another has a similar effect as
mounting an antenna near another antenna.
10.2 Surge Protection & Grounding
Voltage surges can enter the gas detection system via:
Antenna connections
•
•
Power supply connections
•
Connections to other equipment
The earth or ground connection
•
Surges are electrical energy following a path to earth and the best protection is achieved by draining the surge
energy to earth via an alternate path. Wireless devices need to have a solid connection to earth via a ground stake
or ground grid if the soil has poor conductivity. Solid connection means a large capacity conductor (not a small wire)
with no coils or sharp bends. All other devices connected to the controller need to be grounded to the same ground
point. There can be significant resistance between different ground points leading to very large voltage differences
during lightning activity. As many wireless units are damaged by earth potential surges due to incorrect grounding
as direct surge voltage.
REV – 1.3
[34-2900-0207-4 ]
46 |
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