D-CLASS-jumperPassive Intermodulation (PIM) can be a real nightmare. If you are the one specifying the components used in your network, or the one installing them, PIM can be as hard to interpret as a bad dream. It’s the bane of the LTE network, and can cost you a lot of time and money to diagnose and repair.

As we’ve described before, PIM robs the system of precious channel capacity, coverage area, and revenue. A seemingly small PIM degradation of 1 decibel (dB) can rob over 10 percent of a cell site’s coverage area. LTE technology is even less forgiving of PIM than 2G and 3G technology. Every possible source of PIM has to be eradicated for an LTE site to perform optimally.

That’s why CommScope takes PIM so seriously in all of its RF solutions. One of the common, and yet most easily avoided, sources of PIM in the RF path is the installation of an under-performing RF cable assembly. Cable assemblies are commonly referred to as jumpers, and a truly poor performing jumper can degrade the network by more than the 1dB previously referenced. 

As LTE technology evolves, antennas, tower-mounted amplifiers, and remote radio units (RRUs) are increasing their port count, hence adding more jumpers to today’s and tomorrow’s sites. With more jumpers come more chances to increase PIM… or, more opportunities to minimize PIM by choosing the right jumper.

The latest addition to our PIM-limiting portfolio is SureFlex D-CLASS cable assemblies. D-CLASS cable assemblies offer rock-solid Dynamic PIM performance.

Static testing is good… for the lab. Dynamic PIM (per the International Electrotechnical Commission 62037 standard) is a more comprehensive measure of PIM that takes real-world conditions into account. Traditional static PIM testing alone cannot predict how RF path components will react to environmental factors. Tower vibration, varying component installation techniques and other physical environmental factors can all affect the performance of wireless components, even after they have passed all of your site testing.

PIM degradation, due to these external factors, can necessitate revisits to cell sites for remediation, typically requiring expensive late-night work and sector shut-downs.

Stop PIM before it starts. SureFlex D-CLASS jumpers are designed to meet dynamic PIM of -162dBc (4.3-10 series) and -159dBc (DIN) and are backed by CommScope’s limited product warranty for a period of 10 years. You’ll get certified dynamic PIM right out of the box.

The D-CLASS jumpers are available with the latest 4.3-10 series connectors or traditional DIN connectors. The factory-installed SureGuard integrated weatherproofing system is a molded boot designed to seal connector junctions between jumpers and feeders/antennas/ RRU/ amplifiers. You can install in seconds with no special tools, and unlike traditional weatherproofing, SureGuard weatherproofing solutions are reusable.

Need to learn more about PIM? Visit the PIM Site Audit and Avoidance webpage. If you haven’t heard about our revolutionary new way of testing for PIM, check out the Optical PIM Tester. It turns a reactionary testing procedure into a proactive process—all from the safety of the ground. 

Question about the D-CLASS jumpers? Leave me a comment, and I’ll reply.

About the Author

Mike Schaefer

Mike Schaefer is a product line manager in the HELIAX Cable Products group, with 20 years experience in the wireless industry. He holds a bachelor’s degree in management, a professional development certificate in organizational leadership and an MBA in Marketing.

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