Installation/De-installation
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D000043188 en d
– E65C – CU-P40, P41, P42 – User Manual
© Gyr
4.4.2
Choosing the most suitable antenna position in GSM mode
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
CU-P4x
-105 dBm
Cable 10 m: -15 dB
-90 dBm (sufficient)
CU-P4x
-75 dBm
Cable 3 m: -4.5 dB
-109.5 dBm (inadequate)
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
Example 1
Example 2
