Chapter 7 Installation
7.3.2.1 Optimum antenna positioning for assembly in a shaft
7.3.2.1.1 Typical influences on the signal quality
Steel cover
up to -30dBm
Concrete cover
approx. -10dBm
Environmental influences
up to -15dBm
Installation height of the antenna
approx. -5dBm/depth of 15 cm
Vertical/horizontal alignment
approx. -10dBm
Horizontal alignment
up to -15dBm
Centre/edge of the shaft
approx. -10dBm
Other influences
Transmission power of the network operator
Signal losses compared to the reference measurement
Note: Practical example:
GSM level
Position
-67dBm
Reference measurement outside the shaft
-103 dBm
Measurement at a depth of 1.20 m
-95dBm
Vertically on the edge of the shaft at a depth of approx. 15 cm
-83dBm
Centre of the shaft, horizontal on the steel fitting
-89dBm
Antenna turned by 90°
-78dBm
Centre of the shaft, vertical
-75dBm
Plastic pipe used instead of steel fitting
7.3.2.1.2 Possibilities for improving the signal quality
l
Drill a duct for the antenna into the concrete ring on the shaft to bypass the steel cover
l
Insert the antenna extension in an existing ventilation or supply pipe
l
Use special types of antennas (please note: The use of antennas that are not approved by the
manufacturer with devices that are Ex approved will render this approval invalid)
7.3.2.1.3 Procedure for determining the optimum position of the antenna
1. Install the myDatalog4 as described in chapter "Installing the myDatalog4 " on page 33.
During this process, also observe the notes regarding the influences on the signal quality (see
"Typical influences on the signal quality" on page 47).
Note: Have a Extension cable for antenna FME-F/FME-M 5m (206.805) at your disposal just in case.
2. Initiate ALOHA transmission mode (see "ALOHA transmission mode" on page 28).
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