IBUC Operation Manual
Terrasat Communications, Inc.
Rev. A
7-32
General
The Terrasat Redundant Systems are self-contained units that require very little
maintenance.
Standard Maintenance
For optimum performance, inspect the mechanics of the system every six months.
Clean the antenna feeds as necessary to keep them clear of obstructions and check the
cables and connectors for signs of wear, damage or loose connections. Check all fan
intakes and exhausts to ensure that they are free and clear of debris.
FAULT ISOLATION
Transceiver Fault Isolation
The information contained in this section should suffice in determining whether a
Terrasat Redundant System is faulty. The intent is to determine a "GO" or "NO GO"
situation based on alarms indicated through the M&C ports, as well as measuring
certain signals using test equipment.
AC Power Problems / Conditioning
In today's electrical environment there are many types of power related problems that
prevent proper operation of sensitive electronic equipment. These noise problems or
disturbances can be caused by such things as voltage induced by lightning, the
switching On/Off of high power electrical equipment, or utility company actions such as
power factor correction. Serious problems can arise with the occurrence of transients
and spikes causing random errors, or even failure of the PSUI circuitry. Whatever the
origin of the transients, they can be classified in two simple categories:
COMMON MODE: This is the noise voltage that appears equally and in phase from each
signal conductor to ground.
NORMAL MODE: This is the noise potential between the power line conductors. It adds
to and subtracts from the power line sinusoidal voltage wave.
Category A
At the wall outlets (and more than 30 feet from a distribution panel) the typical noise is a
0.5 microsecond rise time up to 6 kV peak, open circuit voltage 100 kHz ring wave with
200-ampere short circuit current capability.
Category B
At the distribution panel one can experience the 100 kHz ringwave above but with 500
ampere current capability and a unidirectional impulse up to 6 kV potential rising in 1.2
microseconds and decaying to half voltage in 50 microseconds. Accompanying this can
be a short circuit current up to 3000 amperes rising to peak in 8 microseconds and
decaying to half value in 20 microseconds.
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