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IBC site PIM locating guide

Permission:

1. IBC site access permission

2. Site DEA permission

Engineers:

1. Operator engineer (clearly with the diagram of the IBC system, and record the detailed

operation steps)

2. LMT operator (do the PIM test)

After preparatory works are being completed, you can enter the actual investigation phase. Actual

investigation follows the "segmented investigation, from near to far" principle. Points out every

piece of RF path should contain multiple nodes, shown as below,

Once operating can exclude multiple nodes determine the issue; IBC sites antenna systems are

usually many nodes, one by one node investigation is very inefficient.

BTS from near and far are based on the top, by the first part near BTS positioned away after

positioning. Because RF path passive inter-modulation interference is characterized by higher

transmit power, passive inter-modulation interference generated by the stronger and closer from

the BTS, the passive inter-modulation interference will be lower with the smaller power as the

attenuation of the RF path insertion loss, so the priority of the jumpers near the BTS will be

higher.

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The method of alternative contrast can be used to confirm the RF path properly or not,

Replace the certain segment RF path with the low PIM load and do the PIM testing (MML:

STRRFTEST).

There will be PIM interference with part 2 when PIM test result is no PIM as the example diagram

below:

Or there will be PIM interference with part1 as the example diagram below:

Low PIM load

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