User's Manual

MODEL 2130 MARKER BEACON
Rev. A April, 2005 5-7
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purposes without written permission from SELEX Sistemi Integrati Inc.
5.3.6.2 Procedure
a. Remove system power and insert wattmeter with 5 W, 50-125 MHz element into RF output transmission line.
b. Reduce the RF power output of the transmitter in small increments until a lower alarm occurs. The reduction must be
done slowly and in small increments to allow the monitor time to respond to the change.
c. Verify that the alarm occurs at the alarm limit or prior to the set alarm limit. For instance if the RF alarm limit is 3 dB
then the measured RF power at the alarm should be = 3 dB.
d. Increase the RF power until an upper RF alarm occurs. Verify that the alarm occurs at the alarm limit or prior to the set
alarm limit.
e. Return the RF power output to normal.
f. Reduce the identification modulation in small increments until a lower alarm occurs. The reduction must be done
slowly and in small increments to allow the monitor time to respond to the change.
g. Verify that the alarm occurs at the alarm limit or prior to the set alarm limit.
h. Return the modulation to normal.
i. Increase the identification modulation in small increments until an upper alarm occurs. The reduction must be done
slowly and in small increments to allow the monitor time to respond to the change.
j. Verify that the alarm occurs at the alarm limit or prior to the set alarm limit.
k. Restore the facility to normal.
5.3.7 Antenna Feed Line VSWR Check
5.3.7.1 Test equipment required
a. Vector Voltmeter or Network Analyzer
b. Directional coupler for use with Vector Voltmeter
c. PMDT
d. Attenuator, 20 dB, Type N
5.3.7.2 Procedure
a. Turn off Marker Beacon transmitter. Disconnect cable to the antenna.
b. If a network analyzer is used, set to 75 MHz, perform 1 port calibration using short, load and open per manufacturers
instructions.
c. Connect the antenna feed line and measure VSWR. Verify that the VSWR is within the tolerance of Table 3-1.
d. If using a Vector voltmeter, place the attenuator then the bidirectional coupler between the transmitter output and the
antenna feed line.
e. Connect the A probe to the forward directional coupler output. Connect the B probes to the reverse directional
coupler output.
f. Turn on the Marker Beacon and log on using the PMDT.
g. Set the modulation to OFF.
h. Perform 1 port calibration using short, load and open per manufacturers instructions.
i. and measure VSWR. Verify that the VSWR is within the tolerance of Table 3-1.
j. Return the Marker Beacon to Normal configuration.