Choosing The Most Suitable Antenna Position In Gsm Mode - Landis+Gyr E65C Series User Manual

Installation/De-installation
4.4.2

Choosing the most suitable antenna position in GSM mode

Example 1
Example 2
D000043188 en d – E65C – CU-P40, P41, P42 – User Manual
The GSM/GPRS modem of the communication unit CU-P4x needs a mini-
mum reception field strength of -99 dBm. See section 5 for a detailed re-
ception field level table.
Attenuation losses result in the antenna cable (–1.5 dB/m) and in the
building structure (depending on construction).
Depending on the reception field strength outside the building and the
attenuation losses in the building structure, the antenna can either be
placed inside or must be placed outside the building, as shown in the
following examples.
Assumptions:

Reception field strength outside the building = –75 dBm

Attenuation losses in the building structure = –30 dB

Distance between the meter and the outside wall = 8 m
Resulting reception field strength at the input of the CU-P4x:

when antenna with 3 m cable is placed in the building = –109.5 dBm

when antenna with 10 m cable is placed outside the building = –90 dBm
-105 dBm
-75 dBm Building structure: -30 dB
Fig. 4.7 Example outside placement of the antenna
In this case the antenna with 10 m connection cable must be placed outside
the building in order to reach sufficient field strength at the GSM modem.
Assumptions:

Reception field strength outside the building = –65 dBm

Attenuation losses in the building structure = –20 dB

Distance between the meter and the outside wall = 8 m
Resulting reception field strength at the input of the CU-P4x:

when antenna with 3 m cable is placed inside the building = –89.5 dBm

when antenna with 10 m cable is placed outside the building = –80
dBm
Cable 3 m: -4.5 dB
Cable 10 m: -15 dB
-109.5 dBm (inadequate)
CU-P4x
CU-P4x
-90 dBm (sufficient)
© Landis+Gyr
21/40