The ARRL RF Noise Identification Web Page
Identify the RFI that interferes with your reception
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. After a hiatus of several years, Craig resumed his operating activities in 2007. It was also about this time that neighbors and friends called upon Craig for assistance with their computers. Out of this Craig developed a small IT business aimed at the home user. Craig says he enjoys the work and its intellectual challenges.
Craig’s Amateur Radio interests include participation in his local SKYWARN activities and several 75-meter Nets. He also enjoys contesting, helping newcomers and always ready to lend 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.
When not on the radio, you’ll find Craig practicing music at home or the organ console at his Church. He holds an A.S. degree in Liberal Arts & Science with a concentration in Mathematics and a minor in music. He’s worked in a variety of fields from tool shops to the allied health. Craig also serves as Webmaster for his Church’s Web site.
About the RF Noise Website
Ken Alexander, VE3HLS first created this website to assist hams and SWLs in identifying annoying noises (QRN) that interfere with reception. It's 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 maintained by Craig Miller, KA1GYB, the RF Noise Website is here to help you identify QRN by comparing it to audio samples of noise from known sources...a kind of "audio fingerprinting".
The samples provided are just a beginning. It's our hope that users will also contribute their own QRN soundbites, either noises that you have positively identified, or those from unknown sources that will be posted in a special area for unidentified (unid) QRN. That way, other users can listen and possibly identify it and solve the mystery for all of us. In this way, everyone can learn to identify - and hopefully eliminate - the noises that ruin our listening!
A Word About The Files
What happens when you click on the links will depend on how your computer is configured. If you have an audio player like WinAmp set up as your default MP3 file player then clicking on a link will likely start WinAmp and play the file with no further action on your part. If you don't have a player configured then your system will likely start downloading the MP3 file and ask you where you'd like to save it.
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.
www.arrl.org/household Household Appliances and Electrical
www.arrl.org/computers Computers and Computer Peripherals
www.arrl.org/emitters Transmitters and Intentional RF Emitters
www.arrl.org/utilities BPL, Line Noise and Industrial Equipment
www.arrl.org/miscellaneous-1 Miscellaneous Equipment
www.arrl.org/unidentified E-mail me if you can identify one of these files!