ARRL

Sounds of RFI

Sounds of RFI

It is not always easy to identify where QRN is coming from and it's even harder to describe it to someone else if you're looking for their help.  Now you can identify QRN by comparing it to audio samples of noise from known sources...a kind of "audio fingerprinting."

If you have a player configured and you'd like to download the file instead of playing it online then you should be able to do so by right-clicking on the link, then click on Save Target As, and specify where you'd like to save the file. Feel free to download any of the files that interest you.

You can also click on the View Waveform button to see what the noise might look like if you could view it on an oscilloscope. The waveform views are 0.1 seconds wide, which is sufficient magnification to see what's going on. For example, noises that are based on 60 Hz line voltage will have 6 pulses in a 0.1 second window (60 Hz / 10 = 6), or six repetitions of a recognizable pattern in the case of the Sony TV waveform.

  • Household RFI

    Check out RF noise from household appliances and electrical equipment. Learn More

  • Computers

    Check out RF noise from personal computers, peripherals and related equipment. Learn More

  • Emitters

    Check out RF noise from known transmitters and RF emitters. Learn More

  • Utilities

    Check out RF noise from electric utilities, BPL and industrial equipment. Learn More

  • Miscellaneous RFI

    Check out recordings of RF noise from other sources that aren't as easy to categorize. Learn More

  • Unidentified

    Check out RFI submitted by people looking for help to identify unknown noises at their location. Learn More

About the Author, Craig Miller, KA1GYB
Craig’s interest in radio began in 1967 when his aunt gave him a Hallicrafters SX-28 shortwave receiver.  As an avid SWL’er, Craig spent many hours listening to stations around the world.  He was first licensed in 1981 as a Novice and began operating in the same apartment he now occupies. Craig’s Amateur Radio interests include participation in his local SKYWARN activities and several 75-meter Nets.  He also enjoys contesting, helping newcomers and lending assistance in times of public emergencies.  Craig reports it is often difficult for him to enjoy Amateur Radio due to RFI and other forms of interference.  Thankfully, he adds that his radio has good filters and DSP processing capability.