ARESLAX, an arm of the ARRL Los Angeles Section, has used a $23,600 grant from Amateur Radio Digital Communications (ARDC) to purchase equipment that will help Amateur Radio Emergency Service® (ARES®) team members to locate and eliminate sources of radio frequency interference (RFI) that could hinder their operations.

“ARESLAX is a 501(c)3 nonprofit organization supporting emergency communication initiatives of the Los Angeles Section’s ARES program,” ARRL Los Angeles Section Manager Diana Feinberg, AI6DF, explained. “Earthquakes and wildfires are the primary disaster threats this region faces. Because these incidents occur without any advance warning, disaster communication groups in the Los Angeles Section must maintain a high degree of readiness.”

Thanks to the grant, Feinberg said, last spring ARESLAX purchased a Fluke ii910 Precision Acoustic Imager, which combines ultrasonic detection with visual techniques to pinpoint an interference source, such as power line noise, and produce photographic evidence. At the same time, ARESLAX used its own funds to purchase a Radar Engineers 243 RFI Locator and spent the summer familiarizing itself with the sophisticated equipment.

“By combining these two purchases with our preexisting equipment, ARRL Los Angeles Section Technical Specialist Chris Parker, AF6PX, believes the Los Angeles Section now has EMI/RFI locating capabilities exceeding those of area utility companies and their contractors,” Feinberg said. ARESLAX would like to eliminate all RFI sources in Los Angeles County.

The equipment will be used across the ARRL Los Angeles Section, the only ARRL Section consisting of a single county — Los Angeles County with 10 million residents and the most populous US county. Terrain ranges from sea level to just over 10,000 feet, including an extensive mountain range. “Using NVIS [near-vertical incidence skywave] on 80, 60, and 40 meters is essential for communicating between all these areas and neighboring counties during major disasters,” Feinberg said.

“For an increasing number of Los Angeles Section hams, EMI or RFI issues have made the HF bands difficult or impossible to use for DXing, contesting, emergency communication, or casual operating,” Feinberg said. She pointed out that the network of overhead power lines that expanded with the county from 1940 through 2010 has now deteriorated, resulting in arcing. “Additionally, our urban noise floor is rising from the millions of electrical devices used by consumers and businesses, including solar charging controllers and grow lights,” Feinberg said. “Unfortunately, the major electric utility companies eliminated their long-standing EMI investigative departments in recent years following personnel retirements and business restructurings. The utility companies now hire outside contractors for locating specific EMI issues, but this approach hasn’t sufficiently solved many problems for hams.”

RFI complaints can go unresolved for years, and tracking down interference sources has been the focus of a corps of technical volunteers. The new equipment makes that job far less time-consuming and more successful, ARESLAX said.

In 2019, ARDC announced the sale of some 4 million consecutive unused AMPRNet internet addresses, with the proceeds to establish a program of grants and scholarships in support of communications and networking research with a strong emphasis on Amateur Radio. ARDC, which manages AMPRNet, said it planned to provide monetary grants to organizations, groups, projects, and scholarships that have significant potential to advance the state of the art of amateur radio and of digital communications.