Training, Installation & Service Manual - Livewire Connections Ltd

12. Low Noise Block down converter (x2) (LNB).
The LNB receives the Ku-band (10.70-12.75 GHz) radio signal,
amplifies it and converts it down to a L-band (950 or 2150 MHz)
Intermediate Frequency (IF). The conversion is controlled by 2
Local Oscillator (LO) frequencies and the LO frequency is locked
to an external reference signal.
The Ku-band interface is WR75 waveguide and the IF interface is
a 75 Ohm F-connector. DC power and 10 MHz external reference
signal are also supplied over the IF cable. The L-band IF output
is routed to the VSAT Interface Module (VIM) located on the
ADU’s azimuth pedestal.
13. Ortho Mode Transducer (OMT). (behind cable screen, not visible
on photo)
The OMT provides a low-loss waveguide interface between the
dual polarised ADU feed-horn and the BUC/LNB.The main
purpose of the OMT is to separate transmitter and receiver
signals and to provide sufficient isolation between BUC and LNB.
The OMT uses the orthogonality of the signals to split and
provide isolation. The OMT also detects the BUC output power
and temperature.
14. Inertial Sensor Module (ISM).
The ISM shall — based on request from the PCM — provide
information about movement of the parabolic reflector, in the
form of samples from gyro- and acceleration-sensors.
The ISM board is:
• Communication as slave of the ADU Bus connecting the
Inertial Sensor Module (ISM), the DC-motor Driver Modules
(DDM), the Polarization Motor Module (PMM), and the
Pedestal Control Module (PCM).
• Collection of contemporary sample-data sets from all sensors
and provide those to the PCM on request. A set of samples
should be collected within less than 100 micro seconds.
• High stability and accuracy 3 axis accelerometer and angular
rate sensor.
• Prepared for wide range 3 axis accelerometer.
• Calibration of sensor offset, gain, and misalignment over
temperature (stored in non-volatile memory).
• Secure fixing to the parabolic reflector.
• Diagnosis of board supplies, sensor inputs, etc.
15. Elevation locking pin to lock the antenna dish in a fixed position
(for safety during service) (not visible on photo).
Removal and replacement of ADU modules
9999
Service & maintenance
98-133966-E2 Chapter 9: Service & maintenance 9-15