Maintenance Guide Part 1

NeTIS MAINTENANCE GUIDE – Version 1.1 23/139
The transmission command indicator, CTX on the UCM is on
Measure the RF signal output from the UCM board
On a spectrum analyser the signal should have the following form:
Central frequency Fo MHz / 10 KHz / division Fo: programmed radio frequency
1 KHz bandwidth
10dB/division
If the spectrum only shows rays or if the spectrum overshoots the 25 KHz width, the UCM
board is defective
When a TETRA radio bench is available, the RF MHz signal will be analysed by the bench
programmed on the RF frequency of your BS. The bench is configured as follows:
Base station test
Duplex test, Tx test
RF MHz carrier
Synchronisation acquisition on 'normal and synchro burst'
Constellation measurement
If the bench does not synchronise, check the spectrum as indicated previously.
If the bench synchronises, it indicates the signal power and its frequency error; it should be
less than +-100Hz. If this is not the case, check the clocks. (See §2.6.4)
The output level of the UCM board: around - 5 dBm.
Pay attention to the power regulation from a set point supplied by the PA (Power Amplifier)
which can vary this level. A check of the power of the PA output must also be carried out.
If no significant signal is present at this level, check that the UCM frequency band is
compatible with the desired value - if so the UCM module is defective.