Anritsu invented and developed a patented technology that pinpoints PIM faults called Distance-to-PIM™ (DTP). DTP shows the location for PIM problems within the antenna system, as well as distance to external PIM sources outside the antenna system. This was an incredible step forward in improving the quality of information received from the on-site PIM test. But one problem still remained for pinpointing external PIM beyond the antenna - DTP could tell you how far away from the antenna the PIM source was located, but not the angle. If the antenna had a 120 beamwidth, the PIM could be located anywhere along the 120 arc at the distance measured by DTP.
PIM Hunter is a patent-pending technology that allows a test technician to pinpoint the location of external PIM beyond the antenna. By walking along the arc of the DTP distance from the antenna with PIM Hunter technicians can pinpoint the source of the PIM typically within a few centimeters.
The PIM hunting process begins with an Anritsu PIM Master MW82119B to inject two high-power test signals into the system under test. The test signals broadcast through the site antenna, exciting any PIM sources in the RF path. These PIM sources behave like CW transmitters radiating the IM3 frequency in all directions. With the PIM Hunter test probe connected to a spectrum analyzer in burst detect mode (Spectrum Master MS2720T or BTS Master MT8220T) or in custom setting (Spectrum Master MS2712E/MS2713E, Site Master S332E/S362E, or Cell Master MT8212E/MT8213E) and an appropriate bandpass filter installed, technicians can “hunt” for these IM3 signal sources along the arc of the distance provided by the DTP measurement of the PIM Master MW82119B. When the probe tip comes in close proximity to a PIM source, the PIM value increases by as much as 30 dB, indicating the precise location of the PIM source. The Identifying Sources of External PIM white paper, found in the Library tab, provides more detail on the external PIM hunting process.