Passive Intermodulation (PIM) Distortion Testing Guidelines

July 19th, 2018

Passive Intermodulation or PIM continues to be a problem for mobile carriers. There are many tools and guidelines that have been developed to make sure you minimize the PIM in your network. We recently held a webinar, PIM Cause and Prevention in Wireless Networks which provides a detailed introduction. Watch the recording of this webinar here.

Passive intermodulation (PIM) is defined as two or more wireless signals mixing together to create additional, undesired frequencies that cause interference or degrade transmission of desired signals in wireless networks. It has long been recognized as an obstacle to network efficiency. With today’s newer technologies, however, PIM is growing exponentially. Data usage is increasing but is not yet being proactively managed. Hypersensitive antennas and radios are susceptible to minute levels of distortion.

Meanwhile, there are more components than ever in the RF path; each is another potential source of passive intermodulation. The incidence and cost of PIM are critical threats to network efficiency, channel capacity, and bottom line profit. Effectively addressing PIM requires an approach that is both holistic and proactive.

Alliance’s partner, Commscope, has developed a program called PIM Happens, Just Not on Our Watch, to comprehensively address PIM issues.

On their web site you will find links to many useful tools and guide. Some of these include:

PIM Calculator

Andrew Solutions has developed a sophisticated PIM Calculator that enables operators to input various RF path components, along with the component PIM specification, model number, and cable length. The PIM Calculator then generates both a typical PIM value (in which the vectors combine randomly), and a worst-case value (in which the vectors all combine in-phase).


The best way to minimize PIM is to work to prevent it during field installation.

At the Andrew Institute educators have developed a new PIM Fundamentals curriculum that focuses on installation and connectorization.

It covers all Andrew products in the RF path including crossband couplers, tower mounted amplifiers, base station antennas, and transmission line products.