Frequency Scan; Receive Signal Level - Sagem -LINK F Installation And Operation Manual

SAGEM-LINK F
Installation and Operation Manual
- Link ID Code
If there is a tributary alarm, verify tributary inputs configuration and connections.
-
- If there are other alarms, or if the link does not work, refer to the troubleshooting section
in this manual
Note any discrepancy in the field commissioning form.

2.3 - Frequency Scan

A special function of the Pilot software is to measure and to record automatically the receive spectrum
around receive frequency. This operation is done on the local terminal only. During frequency scan
process, local transmitter is in mute position, so the link is not operating.
This measurement allows the user to measure interferer levels around receive frequency and to
display it graphically. A record of this measurement is stored in the flash memory, and can be
consulted after installation. In order to check interferer level at receive frequency, it could be
necessary to mute the remote transmitter.
Refer to frequency scan procedure in chapter 3 section 3.3.7.6.
Frequency scan is to be done separately on each end of the link.
Note in the commissioning form the presence of interferers close to the receive signal (adjacent and
second adjacent)

2.4 - Receive Signal Level

In normal weather conditions, the receive signal level depends on :
•
Remote Transmit Power (tolerance : ± 2 dB)
• Remote and Local antenna gains (tolerance : ± 1 dB each)
•
Free Space Path Attenuation
•
Coupler Losses for a 1+1 Hot Stand By system, or flex guide losses for a remote mount system
Compare the actual receive signal level displayed on the main screen of the Pilot software, with the
expected signal level.
As the tolerances are:
•
± 2 dB for the transmit power
• ± 1 dB for the antenna gain (per antenna)
•
± 3 dB for the receive level measurement
•
± 0.5 dB for 1+1 coupler losses
If we want to compare the receive level displayed with the expected calculated receive level, it is
necessary to take in account the tolerances for each parameter :
For a 1+0 system, the worst case for this comparison is within ±7 dB (±2 ±1 ±1 ± 3). For most of the
cases, a typical tolerance is ±5 dB.
So, if the receive level displayed by the Pilot software is less than 5 dB compared to the calculated
receive level, it should be necessary to check again antenna alignment, a propagation problem or a
wrong polarization first. If there is still a problem on the receive level, replace ODU, then IDU, and if
necessary the antenna.
Record the measured receive signal level at each end of the link for each receiver.
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Issue 04 : July 2005