Sagem SAGEM-LINK F - 1.8 - Aligning the Antennas

SAGEM-LINK F 288055571-04
Installation and Operation Manual
Page 20/142
Issue 04 : July 2005
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1.8 - Aligning the Antennas
Antenna alignment is performed with both terminals operating, in normal weather conditions. The
receive signal level (RSL) voltage is available on the ODU BNC connector.
A typical RSL curve at ODU access is given on Figure 1.12 The highest the RSL voltage is, the
highest is the receive signal level.
-90 dBm
1 V
2 V
3 V
4 V
5 V
RSL Voltage
RSL at ODU Input
-80 dBm -70 dBm
-60 dBm
-50 dBm -40 dBm -30 dBm -20 dBm
0.5 V
4.5 V
Figure 1.12 : Typical SAGEM LINK F Receive Signal Level Voltage
Note : RSL is measured at ODU antenna port. In some 1+1 systems involving a coupler or a
remote mount antenna, it is necessary to take in account branching losses to know the actual
power at antenna access.
Optimal performance is done when main antenna lobe is aligned with the center of the remote
end antenna.
It is important to identify main lobe antenna, by rotating the antenna to have the maximum RSL
voltage. Note there is around 25 dB difference between side lobes and main lobes (1.5 V).
Good Alignment