Computer Speakers Picking Up Radio Station

Discussion in 'General Electronics Chat' started by LED Man, Dec 1, 2008.

  1. LED Man

    Thread Starter Active Member

    Jan 15, 2008
    62
    0
    Hey guys,

    My computer speakers are picking up and amplifying a specific FM radio signal. I have noticed that it gets somewhat louder when other things get plugged in to the same surge protector. Does anyone know how to fix this?
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    Are you shure it is an FM radio station?
    A FM signal needs a fm-disciminator to be heard.
    An AM signal can be detected by the base/emitor-diode of a transistor, and more often heard in audio devices.

    On this website there is a possible solution :
    http://www.stevelarkins.freeuk.com/computer_interference.htm

    Greetings,
    Bertus
     
    Last edited: Dec 1, 2008
  3. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
    2,040
    287

    Yep...almost absolutely, positively an A.M. station. Having been chief engineer of a 50KW station for a quarter century, I learned how to get R.F. out of every device known to man. :)

    Ferrite beads around the speaker leads are the best first line of defense. They will solve about 90% of overload problems like this.

    eric
     
  4. LED Man

    Thread Starter Active Member

    Jan 15, 2008
    62
    0
    Hey guys, thanks for the info so far. I just want to confirm that I am in fact picking up an FM signal. I verified this using a clock radio I have in my room. Can I still use ferrite beads or would something else be better? Thanks.
     
  5. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Make certain you are using a shielded audio input cable, not an unshielded headphones extension cord.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Along with using shielded cable, make sure that your speaker connections are clean. 91% isopropyl alcohol on a small cotton swab used on the jack and plug may help.

    Make sure your power connections are clean.

    Try swapping out your surge protector with a new one. If it's been in use for awhile, it's likely that it either has corroded sockets and/or it's been subjected to the effects of a lightning strike. If a lightning strike was nearby, the MOV(s) inside the protector could be fried and you wouldn't know it.
     
  7. LED Man

    Thread Starter Active Member

    Jan 15, 2008
    62
    0
    Wow it's pretty much completely gone now, that was it. I still hear it but its very faint, I'm going to try the ferrite beads to get rid of all the interference. Thanks.
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    What was it?
     
  9. LED Man

    Thread Starter Active Member

    Jan 15, 2008
    62
    0

    This got rid of pretty much all the interference. I'll try the other suggestions too. Thanks guys.
     
  10. rbxslvr

    Member

    Nov 30, 2008
    14
    0
    I've also had problems with that in the past. My house is a few hundred feet from a radio tower. Everything in our house used to be able to pick up FM 101.9 (our local station). They moved to another town though, so no more problems.
     
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