RF noise is a common topic of discussion among radio amateurs. The proliferation of electronics has overwhelmed and complicated the noise environment; they are no longer just power lines. Unless isolated from civilization, most radio amateurs experience radio frequency interference (RFI) – sometimes without even realizing it, although the spectral bands of modern transceivers make radio frequency noise much more obvious. Various approaches have been taken around the world to tackle the deteriorating noise level, with some addressing poor regulation.
“We all want to improve our ability to copy the weak by increasing our signal-to-noise ratio,” said Alan Higby, K0AV, in March. NCJ article, “Tracking RFI with SDR one source at a time.” It offers practical methods for individual radio amateurs to improve their own noise environment. “We can do this by reducing the noise on every tape we work on. Reducing the noise level increases the relative signal strength of weak signals. Those in a typical living environment find that locating and eliminating RFI sources is an endless process. It’s a lot like weeding a garden. ”
International Amateur Radio Union (IARU) warns against complacency. “Radio enthusiasts can’t relax because even if the desired noise limits are agreed, there are many fraudulent manufacturers and retailers who will be happy to sell noise-generating devices, leaving filter circuits to reduce costs,” a statement from IARU. IARU called on members of the societies to get involved.
The FCC Technology Advisory Board (TAC) – Commission Advisory Group – an investigation has been launched in 2016, looking at changes and trends in downstream spectrum noise to determine if noise is increasing and if so, by how much. The TAC encouraged the FCC to undertake a comprehensive noise study in 1998 and warned the FCC not to implement new spectrum management techniques or initiatives without first completing one. In 2017, the FCC’s Office of Engineering and Technology (OET) invited comments on a series of spectrum management (TAC) questions. ARRL, in its comments, took the opportunity to urge the FCC to reinstate the 2016 TAC noise level study, which, as ARRL claims, was discontinued before it even began. ARRL called on the FCC to “deviate from the traditional regulatory model”, which restricts transmitters only, and called for a “holistic” approach to transmitter and receiver operation.
Greg Lapin, N9GL, represents the ARRL at the TAC and chairs the ARRL RF Safety Committee. “Perhaps the best result we got was an indication that illegal devices, mainly LED lights, were in circulation and the Bureau of Law Enforcement agreed to look into it,” he told ARRL. “We never heard what they found out, but I recently bought some LED bulbs online from a website in Texas and they sold lights not approved by the FCC – and I didn’t seem to care.” aimed at tackling 5G issues.
ARRL offers a wide range of RFI information on his website.
Paul Giancolo, W1VLF, will propose “Finding and Correcting RFI” as part of ARRL training network a series of webinars, on Tuesday, April 20, at 17:00 UTC.
MiR Ritz, Director of the Northwest Division of ARRL, W7VO, will propose “High Frequency Noise Reduction” as part of ARRL training network a series of webinars on Thursday, April 22, at 19:30 UTC.
Some national regulators are addressing noise complaints, although not necessarily from users of licensed services. In the UK, the regulator Ofcom recently sent engineer only 30 minutes after receiving a signal for interference in an unprotected licensese-released keychain devices in this case. “In rare cases, defective or unauthorizedsThis equipment can interfere with nearby technology and prevent it from working properlySaid Ofcom. It is unclear whether interference with licensed services will receive the same level of attention.
Participants in the International Radio Amateur Union (IARU) Region 1 conference in Germany in 2017 devoted a significant discussion to noise issues and the need to monitor noise levels. The Deutscher Amateur Radio Club (DARC) is working on the development of a noise measurement system that approximates the methods used by the International Telecommunication Union – Radiocommunication Sector (ITU-R). DARC reported that 35 of these electrical noise zone monitoring systems (ENAMS) have been delivered and are looking for another 20 sites as part of efforts to monitor noise interference in HF bands. DARC said ENAMS could help make scientifically reliable statements about interference levels.
The IARU Region 1 EMC (Electromagnetic Compatibility) RF Noise Measurement Team meets quarterly to share ideas and experiences. One of the projects under consideration is the development of a common database to collect the results from different monitoring stations for further analysis.
IARU sees wireless power transmission (WPT) technology as an imminent threat of noise, especially from WPT (WPT-EV) electric vehicle charging systems. “For the amateur service, given the planned density of WPT-EV systems, it is estimated that there will be a widespread and serious impact on its operation in the vicinity of WPT systems” from parasitic emissions, said in 2019. ee publishers article, written by Amateur Radio Companies Concerned about High Frequency Noise. The article added: “To ensure a low probability of harmful interference in radiocommunication services, further research is needed, including an assessment of actual equipment, mitigation techniques and other measures to improve WPT-EV systems.
The South African Radio League (SARL) encourages radio amateurs to create their own systems for monitoring radio frequency noise using a key and a Raspberry Pi. The HF noise monitoring system takes samples of the 12 × 1 MHz band every 2 minutes, recording the data in a file.