9500 MXC User Manual
3DB 23063 ADAA - Rev 004 July 2007 Vol. VI-B-19
IF Temperature
Modem / IF temperature out of tolerance. This is a warning alarm.
Probable Cause
1. The ODU is faulty, either with an overheating problem or with a faulty
temperature sensor.
2. Environmental temperature excessive. The ambient must not exceed 55
o
C
(131
o
F), which is a shaded temperature limit (no solar gain).
Recommended Actions
1. Check for other ODU related over-temperature alarms: Power Detector
Temperature, and Transceiver RX Temperature. Also check the PA Current
alarm.
2. Use the CT Performance screen to check ODU Temperature and Detected Tx
Power. ODU Temperature should not exceed 90°C, and then only in extreme
ambient and maximum Tx power conditions. If Detected Tx Power is not
normal, this may be as a result of general overheating, or a component failure.
• If there is correlation between other temperature alarms and/or the ODU
Temperature reading, a general overheating of the ODU is indicated. If
this cannot be associated with very high ambients, a faulty ODU is
indicated. The ODU must be replaced.
• If there are no other alarms, the ODU Temperature is normal, Detected Tx
Power is normal, and the ambient is not high, then a localized alarm
measurement fault is indicated. The ODU should be replaced.
3. Where an environmental temperature problem is suspected, use the CT
Events Browser and History screens to see if there is an alarm pattern
associated with ambient temperature and sun position. If confirmed, a sun
shield should be installed for the ODU.
Additional Information
This temperature output is used to maintain correct Modem/IF calibration over
temperature. The Modem/IF is located in the ODU.
Solar gain on the ODU can add 10
o
C or more to the internal ODU temperature,
therefore in ambients in excess of 45
o
C (113
o
F), solar gain can result in
over-temperature situations.
Detected Tx Power should be within 2 dB (typically within 1 dB) of the Tx
power setting in a RAC/Radio Plug-ins screen when ATPC is disabled. In
situations where ATPC is selected, refer to the commissioning record for
guidance on a normal Tx power indication.
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