Connect with us

AM Radio Interference

Discussion in 'General Electronics Discussion' started by dm99, Oct 29, 2012.

  1. dm99

    dm99

    26
    0
    Oct 29, 2012
    I live above a bar/restaurant and for most of the day I cannot pick up much on my AM radio. When the bar is closed much of the interference goes away. I spoke with the owner of the bar and he told me he's be willing to work with me if I can figure out exactly what's going on.

    How do you start to figure something like this out?


    A description if I can get anywhere with this. . .

    During the day and evening there are silent stations which interfere with some of the legitimate AM stations. At night or in the morning before the bar opens these are gone. The tuned light will light on most of these.
     
  2. CocaCola

    CocaCola

    3,635
    4
    Apr 7, 2012
    It's likely a combination of many factors...


    • Physical presence of people interfering with signal, remember walking around or in the proximity of the bunny ears on your TV back in the day :)
    • Cell phones and other radio devices in the vicinity, yes even thought they are on a different frequency in close proximity they can and will interfere...
    • Additional neon signs or other electronic devices powered up during business hours?
    • Additional lights during business hours, florescent?
    • Something else in the vicinity that just happens to coincide with the bar hours, like another business with machinery or what not...
    To name a few...


    Do your radio stations have Internet mirrors, or possibly Cable TV mirrors? If so you might consider using those... Or consider a larger antenna on the roof...
     
  3. donkey

    donkey

    1,286
    56
    Feb 26, 2011
    the fact that its AM might make my answer a little less likely. but is there a DJ or jukebox that is not wired to the house speakers? they could be using a transmitter for this. even a wireless microphone.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,689
    Jan 21, 2010
    If he's willing to work with you, perhaps you can take an AM radio down there to establish that the radio picks up the interference in the bar, then be with him as he either opens up or shuts down. See if the interference starts as something is turned on and/or stops when it is turned off.

    There may be more than one source. If you can determine what is causing it, it may be possible to eliminate the problem at the source.
     
  5. dm99

    dm99

    26
    0
    Oct 29, 2012
    I do know that it starts suddenly, persists all night, and washes out most of the AM dial throughout the entire bar/apartment.

    I'm thinking the lights, or something else that's on all night is probably the cause. The bar owner was convinced that it must be the microwave ovens, but we ruled that out.

    There's no DJ equipment, it's a sports bar. I've never seen microphones either.

    Why would the lights in the bar affect the radio and not the lights in my apartment or anyone's home or business?
     
  6. CocaCola

    CocaCola

    3,635
    4
    Apr 7, 2012
    Everything electrical effects radio, but everything electrical is not created equal... The electrical stuff in your house and other businesses do effect the radio, it's all a matter of what is more powerful the legit radio signal or the interference signal (ask the few successful TV channel hijackers about this)... All it takes is a silly irregularity in one of the light fixtures or the wiring to create all sorts of isolated interference... It might very well be one light fixture or neon sign that is causing all the issues or compounding a bunch of other smaller things...
     
    Last edited: Oct 30, 2012
  7. dm99

    dm99

    26
    0
    Oct 29, 2012
    Here's what we're going to do. The owner is going to turn the radio on in the bar as soon as he gets in tomorrow. Then he's going to proceed as usual and see what happens. I'll let you know what we discover.

    He told me that he has noticed that the AM stations are washed out on the public address system too.
     
  8. gorgon

    gorgon

    603
    23
    Jun 6, 2011
    If there is a dimmer cicuit on the lights, you may have a HF field generated that blanks out other AM signals. Or just a bad connection in the light circuits.
     
  9. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,689
    Jan 21, 2010
    Or dodgy HID lights.
     
  10. dm99

    dm99

    26
    0
    Oct 29, 2012
    So, he thinks he narrowed it down to the televisions in the bar. He said that when he turned them on the radio totally washed out. There are 22 television sets throughout the place.

    Plausible?
     
  11. dm99

    dm99

    26
    0
    Oct 29, 2012
    We narrowed it all down to one TV set.
     
  12. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,689
    Jan 21, 2010
    Yes

    Excellent.

    It may be worth testing (if you can) that the problem remains if this set is plugged into a different outlet, or if the antenna connection is removed.

    Let's assume that unplugging the antenna has no effect, and neither does plugging it into a different power outlet.

    This probably means there is a fault with this set (especially if it is the same make/model as others which don't wash out the radio).

    So, what do you do now?

    Ideally for you, he will decide to replace that set. However let's assume he's not going to pay to fix this.

    1) you can buy him a new TV

    2) You can pay to have it looked at professionally (possibly leading back to (1)

    3) You can try to find something to suppress interference on the power line and plug the TV into that.

    In theory, he may actually be liable for the interference. But it is probably not worth pressing that point too much, especially if this is also your watering hole.

    What does he want to do? Have you thought of offering him some $$$ (less than the price of a new TV) to help him upgrade it? It all depends on him. But he's come to the party so far by trying to track this down, maybe you can reciprocate a little just to be neighbourly.

    Hey, maybe you can upgrade you own TV and give him your old one?
     
  13. Timescope

    Timescope

    43
    0
    Aug 30, 2012
    I have also noticed that the PFC circuits of LCD tvs generate interference that washes out my FM radio. The power supply circuits of most LCD tvs I have seen are not screened and may radiate interference.

    Timescope
     
  14. dm99

    dm99

    26
    0
    Oct 29, 2012
    They're all the old monstrous square ones with the glass tube.

    We noticed something odd about it. Every couple minutes the picture squeezes in like an hourglass for just a few seconds. Could this be related?
     
  15. dm99

    dm99

    26
    0
    Oct 29, 2012
    He's got a contract with a company to maintain the system, he's going to have them come out and investigate. I don't believe he technically owns the equipment.
     
  16. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,689
    Jan 21, 2010
    In that case he has a fault and they should fix it.

    Everyone should be happy. :)
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-