User's Manual

P. G. TM0060
3-4
3.3 OPERATING INSTRUCTIONS
The bidirectional amplifier has no external controls. When powered the unit will amplify
signals in each direction.
When the green light is on, bias conditions of active devices in all the RF paths are within
specifications and the downlink power is above the minimum preset limit. The red
FAULT light goes on whenever active devices in the RF paths have failed or the downlink
output power is too low. Corrective action is to check if the input power is correct and
then to check the fault conditions as indicated below.
3.4 FAULT CONDITIONS
If the FAULT light is illuminated it indicates that one of the following conditions have
occurred. Two LEDs on the side of the unit show the status of the RF and DC bias
alarms and indicate the source of the fault conditions.
3.4.1 Low RF power (“PWR” LED on) - Check the level of RF power out of the
amplifier by connecting a meter or spectrum analyzer to the Test Port J3. The actual level
is higher than the measured level by 24 dB at PCS frequencies. If the RF fault option is
enabled a fault will occur if the RF power falls below approximately +5 dBm.
By measuring the RF input power at J4 the correct functioning of the amplifier can be
checked. The gain should be approximately 20 dB minus the inserted attenuation.
3.4.2 DC Bias Change (“BIAS” LED on) - A DC bias alarm indicates a fault in the
amplifier. This condition mandates replacement of the amplifier.