User's Manual

MODEL 2130 MARKER BEACON
Rev. A April, 2005 5-9
This document contains proprietary information and such information may not be disclosed to others for any
purposes without written permission from SELEX Sistemi Integrati Inc.
5.4.4.2 Procedure
a. A facility shutdown is required. Issue a NOTAM.
b. Disconnect the transmission line under test at both ends.
CAUTION
Megging transmission lines connected to antennas or other components may cause damage to equipment.
c. Connect the insulation tester between the center conductor and the shield. Operate the tester in accordance with its
instructions.
d. Measure and compare the insulation resistance against Table 3-1.
e. If the measured insulation resistance is less than the applicable tolerance, corrective action must be taken. If
significant change is found from the previous readings, corrective action should be initiated to prevent further
deterioration of the cable.
NOTE
If any cable measures less than infinite insulation resistance, especially new lines or those that previously measured
infinity, consider corrective action even though the measurement is within prescribed tolerances.
f. Restore the Marker to Normal condition.
5.4.5 Measure RF Cable DC Resistance.
NOTE
High DC resistance in RF lines with connectors attached usually indicates a faulted connector damage to the shield
and/or center conductor. Also moisture within a cable and/or RF connector may result in corrosion, with a resulting high
dc resistance path.
5.4.5.1 Test Equipment required
An appropriate DVM with the capability to measure low DC resistance in the order of 1 to 5 ohms.
5.4.5.2 Procedure
a. A facility shutdown is required. Issue a NOTAM.
b. Disconnect the transmission line under test at both ends.
c. Connect the insulation tester between the center conductors at both ends of the cable. Measure the dc path
resistance and compare against Table 3-1.
d. Connect the insulation tester between the shields at both ends of the cable. Measure the dc path resistance and
compare against Table 3-1.
e. Restore the Marker Beacon facility to normal.
NOTE
The measured values and Table 3-1 tolerances are to be used as a guide. This is a point at which maintenance action
should be initiated to prevent further deterioration of the RF cable or quality of service. Exceeding this tolerance does not
indicate that a facility should be removed from service.