OPW M2010-EU, Installation Manual

Page: 128 / 149

Antenna Installation
Each antenna has its own radiation diagram.
The radiation diagram shows the directions where the antenna can transmit the signal with the most power.
The diagrams below show the directional patterns of the probe antenna and the receiver antenna.
To have the best reception without signal loss, the antennas must be pointed in the same direction.
EXAMPLE:
You cannot set up the receiver antenna horizontally if all of the probe transmitters are all set up
vertically. This would result in almost complete loss of signal because of different polarization
(horizontal instead of vertical).
The probe antenna does not transmit or receive from its top, but through its side (see the illustration above).
The antennas must always be kept parallel to each other.
If it is necessary to install a probe antenna under asphalt horizontally, the receiver antenna must also be
installed horizontally.
Wireless probes use a battery with a low frequency for data transmission. The bandwidth used is 169.4 MHz
with a narrow canalization of 12.5 KHz. Since the transmission occurs underground, his band has low
attenuation because of blockage or surrounding land.
This transmission must not be mistaken for wi-fi which uses higher frequencies of 1.2-2.4 GHz. Wi-fi does not
have the minimum requirement to transmit through the manhole.
If the antennas are installed outdoors, the transmission can reach to 1 km. For usage at service stations
where the antennas are installed underground (integrated into the probe head) the distance of transmission
in normal conditions is 100-200 m.
Normal conditions include installations where it is not necessary to have a
Faraday Cage
that would block
the signal transmission.
Common manhole constructions that block signal transmission like a Faraday Cage include:
Doc. No.: M2010-EU Rev.: 13
Page 128 of 149