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Chapter 3 - Routine Maintenance
Confidential and Proprietary Information of ZTE CORPORATION 77
[
Test procedure
]
The following steps describe how to check a lightning protection arrester.
Here we take a 1/4
λ
wavelength lightning protection arrester for example.
1.
Power off all the ETRM modules on PSM.
2.
Loosen the jumper connectors jointed with both ends of the lightning
protection arrester.
3.
Calibrate the SiteMaster.
i.
Press the START CAL button to perform zero calibration prior to the
test.
ii.
Connect the open-circuit calibration terminal (OPEN) with
RF/REFLECTION on the backplane, and then press ENTER.
iii.
Connect the short-circuit calibration terminal (SHORT) to RF/OUT,
and press ENTER to perform load calibration.
iv.
Select SAVE SETUP to save the calibration (optional).
4.
Connect the SiteMaster to one port on the lightning protection arrester
through a testing cable.
5.
Connect the other port on the lightning protection arrester with a
matched load.
6.
Read the SiteMaster, and judge whether the return loss of the lightning
protection arrester is within the valid range.
7.
Repeat steps (4) ~ (6) to measure the return loss of another port on
the lightning protection arrester.
8.
Adjust the multimeter to X10K and then measure the resistance of the
conductor in the high-frequency sockets at both ends of the lightning
protection arrester.
9.
Adjust the multimeter to X1 and then measure the resistance between
the conductor in the antenna and the ground.
[
Normal result
]
Technical indexes of the lightning protection arrester comply with the
product specifications. The tested return loss is required to be more than
20 dB.
The resistance of the conductor in the high-frequency sockets at both ends
of the lightning protection arrester is more than 20 M
Ω
.
The resistance between the conductor in the antenna and the ground is
approximately 0
Ω
.
[
Troubleshooting
]
Replace the lightning protection arrester if the result is beyond the valid
range. For more details, refer to “Antenna Feeder Lightning Arrester”.
[
Recovery after test
]