ARRL

Computers

The files in this section are recordings of RF noise from personal computers, peripherals and related equipment. If you can match noise at your location to one of these files then you can be confident that you know where your noise is coming from. Now all you have to do is find it and fix it!

RFI Noise

  • Computer Monitor

    Contributor: Ken, VE3HLS
    Noise Source: Computer monitor
    Where Found: 5975 kHz USB, but occurs throughout the lower HF bands
     

    Listen

    monitor.gif

  • Logitec Computer Speaker

    Contributor: Ken, VE3HLS
    Noise Source: Computer speakers, made by Logitech
    Where Found: 10051 kHz USB, and other locations in the HF band. The occurrances of noise are about 6 kHz wide.
    Notes: The speakers were purchased about 5 years ago. They have a circuit in them that turns them off after several minutes of inactivity. They turn themselves on when they detect audio at the input. When off they emit the RF noise in the file, and go quiet when they are on.


    Listen

    compspeaker.gif

  • Cable Internet Router

    Contributor: Henry Baum
    Noise Source: Cable Internet Router
    Where Found: 6m and 2m bands.
    Notes: "This noise is heard on 6 meters and 2 meters only. I was so annoyed by the noise for about a year till I found out about the noise. This is the sound of my Cable internet router. The noise is only heard on a few frequncies on 6 meter SSB. The recording is of 6 meter SSB."


    Listen

    henry_router.gif

  • 5-Port Ethernet Switch

    Contributor: Phil, VA3KDC
    Noise Source: 5-Port Ethernet Switch
    Where Found: Above 9 MHZ
    Notes: "This recording is on a grundig FR-200 receiver The noise is from an SMC EZ 5 port ethernet switch. This noise is heard at intervals up and down HF, most noticible above 9 mHz. Recording was made in AM mode"


    Listen

    va3kdc_switch.gif

  • Toshiba Cable Modem

    Contributor: Alex, KC5CMW
    Noise Source: Toshiba Cable Modem
    Where Found: 40m Band
    Notes: "I have found that my computer cable modem emits a carrier with a data stream imbeded about every 30 kHz on the 40 meter band. I also notice it on the 10 MHz WWV freq. The modem is a Toshiba model pcx2600."


    Listen

    kc5cmw_modem.gif

  • HP Model W1907 LCD computer monitor

    This sample was taken at 147.10 MHz FM.  The interference signal appeared every 240 kHz above and below 147.10 MHz and throughout the entire 2-meter band.

     

    Listen

    HP_W1907_Monitor.gif