As our lives become filled with technology, the likelihood of electronic interference increases.  Every lamp dimmer, garage door opener or other new technical “toy” contributes to the electrical noise around us.  Many of these devices also “listen” to that growing noise and may react unpredictably to their electronic neighbors, including Amateur Radio transmitters.

Sooner or later, nearly every active Amateur Radio operator will have a problem with interference.  This could involve interference to a neighbor's equipment, or, more likely, some form of intererence to Amateur Radio from the noisy devices that can sometimes even be found in our own homes.  The good news is that most cases of interference can be cured!  The proper use of “diplomacy” skills to communicate with a neighbor and standard technical cures will usually solve the problem.

What Is It?  While this question may seem intuitive, it may be the wrong one to ask if you have an RFI problem.  By Ed Hare, W1RFI.

Electronic Noise Is Drowning Out the Internet of Things.  Our increasingly connected world needs better protection against RF noise pollution, By Mark A. McHenry, Dennis Roberson & Robert J. Matheson.  IEEE Spectrum, August 18, 2015

Hunting Down RF Noises.  Find noise sources both outside and inside your home with a systematic approach, by Michael Foerster, W0IH.  QST February 2015, p 45.

Locating RF Interference at HF.  A proven and practical approach to dealing with RFI from grow lights and more, by Tom Thompson, W0IVJ.  QST November 2014, p 33.

A Quick Look at Radio Frequency Interference, by Joel R. Hallas, W1ZR.  QST May 2009, p 61.

Interference Primer - Parts 1 and 2 Derived from QST Lab Notes columns.  Contains general information on Radio Frequency Interference.

• A Ham's Guide To RFI, Ferrites, Baluns, And Audio Interfacing by Jim Brown, K9YC. (1st Link)
• A Ham's Guide To RFI, Ferrites, Baluns, And Audio Interfacing by Jim Brown, K9YC. (2nd Link)
• In Compliance Magazine provides a tutorial on ferrites Using Ferrites to Suppress EMI.
• Audio Systems Group, Inc. Publications 
  Provides a number of articles and application notes related to sound systems.  Some of these articles pertain to interference to audio systems from both power and RF sources.
• The EMI - RFI Page, by Mark Demeuleneere, ON4WW.  In this page, Mark provides some interesting background on some of his more memorable RFI experiences in Belgium.  As Mark puts it, “It took quite some time just to document these RFI cases.  Imagine how much more time was invested in finding and solving them!”
• The EMI - RFI Page, by Chris Gare, G3WOS.
• Variable Speed DC Motor Washing Machine RFI Fix, by Gene Preston, K5GP.
• Grow Light Electronic Ballast RF Interference, by W0QE.
• eEngineer provides an EMI/EMC Glossary as well as several other RFI pages pertaining to RFI.
• Lutron provides Applications Notes
• V-Soft Communications® LLC
  Provides AM FM Zip Code Based Signal Strengths: Field strength vs. Zip Code

Information for Electric Utilities

• Center for Devices and Radiological Health
  Addressing EMI in medical devices
• Welcome to the RSGB EMC Web Pages
  E-book-"The RSGB Guide to EMC" (Electromagnetic Compatibility)
• EMC Standards
  Contains a list that details some of the major electromagnetic compatibility (EMC) standards in place worldwide.
• Radioing eEngineer has a page on Radio Frequency Interference (RFI)
• The United Kingdom's Radiocommunications Agency has a Radiocommunications Agency EMC Awareness page with EMC/RFI information for the non-technical person and the general public.
• See www.aerorfi.org for information on interference in the aircraft band.  Much of this information also applies to the broadcast and Amateur bands.

Special thanks to George F. Munsch, W5VPQ for providing these documents.  They contain useful and comprehnsive information for both RFI locating and noise mitigation.  By Wilbur R. Vincent, W6PUX, George F. Munsch, W5VPQ, Richard W. Adler, K6RWA, and Andrew A. Parker, WV1B.

• Power-Line Noise Mitigation Handbook for Naval and Other Receiving Sites
  This is a comprehensive manual that describes how to understand, locate and correct power line noise.  A must for every utility or RFI troubleshooter.
• The Mitigation of Radio Noise And Interference From On-Site Sources at Radio Receiving Sites
  Provides information when sources are located within the boundaries of a site.  In most cases, these sources are electrical or electronic consumer devices.