User Manual

AS4000 Operations and Maintenance
Section
605-0000-431
6
. Issue 1.6. Date3/2/99
DLP-014
Page 13 of 60 © Copyright Airspan Communications Corporation 1999
POWER
METER
CT
15W
Termination
RF Power meter
connection when
measuring Modem
Shelves 1 & 2
TX Output Power
DIP/LNA1 TX Filter
15W
Termination
POWER
METER
CT
RF Power meter
connection when
measuring Modem
Shelves 3 & 4
TX Output Power
DIP/LNA1 TX Filter
Figure 7-9. Power Level measurement Test Set-up
4. Restore power to the rack.
5. Put one modem into service and measure the output power. 18±0.5dB
6. The TX output power level is maintained by a power control loop in the system. For
the power loop to work the CT RF card needs a power level greater than 21.75dB
this can be achieved by using the Sitespan to set three users in service without any
STs in operation. This forces the three modems ( i.e. two modem cards) to stay in
the high rate acquisition mode. Three users provide an output of 22.8dB± 0.5dBm.
7. For the CT to reach it’s nominal output power from zero using the control loop
would take a considerable length of time. To bypass this process, the power control
loop may be overridden using the Sitespan to set the TX power the control voltage.
Proceed as follows:
a) Using the Sitespan select the RF Card view from the Shelf view. See Figure
7-7.
b) Set the transmitter volts to 2.2 volts by using the Up/Down button. Observe
that the auto levelling sets the Output power to 22.8± 0.5dBm. (note each
click of the up/down button has to be communicated to the shelf controller
and time should be allowed for this to happen).
c) Record results
d) Switch off rack. by placing both breakers in the off position.