Hughes Electronics recently announced that research it conducted in cooperation with London Southbank University found that humidity makes a significant contribution to passive intermodulation (PIM) in cellular networks. Along with the research, the collaboration between Hughes and the university authored a white paper and developed the WaveWay connector system. The white paper, titled “Connector Related PIM,” “sheds new light on some unknown sources of PIM [and] has found that humidity deposits a layer of salts and other airborne contaminants which interfere with ‘clean’ signal transit and have invented a novel way of dealing with it,” Hughes Electronics stated.
The company further explained, “PIM is a series of resulting signal harmonics and distortions that emerge between two or more interacting signals when transmitted through passive components such as cables and connectors, causing unwanted interference and degradation of wireless communications. 4G, 5G and future-generation networks require stricter signal to noise ratios (SNRs) and the issue of PIM must be addressed if cellular capacity is to be maintained.”
The salts referred to are “almost impossible to see,” Hughes noted. They are “deposited during the evaporation process,” and are “electronically conductive, and play havoc with skin effect signal transmission.” The salts “instigate surrogate (signal) pathways, causing parallel path and harmonic signals and distortions, which are a root cause of PIM,” the company elaborated.
Hughes Electronics’ new IP68-rated cap for connectors includes a humidity indicator. “The cap, which protects open connector interfaces from mechanical damage, dust and humidity is transparent and incorporates an ingenious blue indicator in the top of the cap that visibly turns to pink when it detects the presence of humidity,” the company said. The image on this page shows what the cap looks like when it is and is not exposed to humidity. Hughes continued, “It is possible to determine the amount of humidity present by the shade of color. Instructional information is provided with each cap to help the user.”
The company adds that the cap has been approved by “most major UK networks” and is economical to deploy. Hughes emphasizes that the cap “can save companies many wasted man hours of PIM diagnosis and expensive trial-and-error remedies tracking down sources of PIM they simply cannot see.”
The screw-on cap does not require special tools to install. They are available for 7/16 and 4.3/10 connectors.