Anritsu has developed the PIM Master to verify if receiver interference at a cell site is due to an intermodulation product of two or more transmit frequencies, also known as passive intermodulation (PIM).
The PIM Master generates two high power tones in the transmit band of a base station and Anritsu’s family of handheld RF instruments’ PIM Analyzer measures the 3rd, 5th, or 7th order intermodulation products in the receive band coming back down the same cable. And the GPS option will record the location of the measurement.
PIM Testing versus Line Sweeping
A PIM test cannot, however, measure VSWR. This means the test set will not see an open or short condition, unless the fault displays non-linear behavior. A return loss figure that is failing will not be determined with a PIM test measurement.
Components deteriorate as they age due to a number of issues, including poor mechanical design, poor installation, and moisture ingress (which is the most significant). On-site faults can mostly be categorized into two main types: linearity related and impedance related.
PIM testing measurements reflect the overall linearity of an antenna feed line and Line Sweep measurements reflect the overall impedance matching of all of the components in an antenna feed line. Both tests need to be performed to ensure the overall quality of an antenna feed line. Passing one type of test (PIM or Line Sweep) does not guarantee the other test will pass.
- Noise Floor
- Distance-to-PIM (DTP)