PIM testing should be conducted while subjecting the device or line under test to a dynamic stimulus. If the magnitude of the PIM that is being measured exceeds the pass / fail limit during the test, then the device or line has failed even if the PIM returns to a low level after the dynamic stress has stopped. Figure: Dynamic Stress by Tapping a Loose Connection shows this. This trace was created by tapping on a loose RF connection, which shows that PIM in this test situation is very unstable under dynamic stress and then very good when the stress has stopped. Definitions for how to apply dynamic stimulus are defined by IEC62037 for RF cable assemblies, RF cables, Filters, and Antennas. The only problem is that this work was done with FACTORY testing in mind. The IEC specification does not currently address how to apply dynamic stress in the field. Operators, therefore, need to define their preferred test methods. The MW82119A PIM Master has the PIM versus Time measurement mode, which supports dynamic testing and keeps track of the worst case value for the duration of the test. It also compares the measured values to the pass / fail limit that you have set.

Note that the peak PIM values are displayed in red because the measurement exceeded the upper limit setting.

In this example, the measurement exceeds the set limit at three locations. The Pass Indicator displays FAIL in red letters. Also note that the measured PIM and Peak PIM values are displayed in red numerals.