Horrible electrical interference
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Thread: Horrible electrical interference

  1. #1

    Horrible electrical interference

    I put on KYW when I got up this morning, as I do almost every morning, only to find it completely unlistenable. I am in South Philadelphia and there is some horrible reverberating electrical interference blowing almost the entire AM band off the air. The only stations getting through are 610 and 990. I called KYW's news room and a pleasant fellow who answered the phone said he would report it to the engineer, but that they had no other calls. I tried multiple radios. Anyone else have this happen this morning? Any thoughts as to what would be strong enough to blow almost an entire band off the air? I've never seen this happen before.

  2. #2

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    Quote Originally Posted by doowopfan View Post
    I put on KYW when I got up this morning, as I do almost every morning, only to find it completely unlistenable. I am in South Philadelphia and there is some horrible reverberating electrical interference blowing almost the entire AM band off the air. The only stations getting through are 610 and 990. I called KYW's news room and a pleasant fellow who answered the phone said he would report it to the engineer, but that they had no other calls. I tried multiple radios. Anyone else have this happen this morning? Any thoughts as to what would be strong enough to blow almost an entire band off the air? I've never seen this happen before.
    That's why CBS should put KYW on 96.5. I live out in Chester County and I notice bad interference going down Paoli Pike around the traffic signals. My parents are in Cherry Hill. Whenever I drive down Kings Highway, there is very bad electrical interference from the PSE&G wires. I don't have HD radio in my car but, I do have a couple at home and KYW sounds really good on WIP-HD2.

  3. #3
    If you still own a battery powered AM radio, walk around your neighborhood and find out where the interference is worst. Years ago, I found interference strongest near a transformer on a utility pole. I called the electric company to report it. They transferred me to someone who was VERY interested, and they came out to fix it in less than a day. If it is more widespread, report it anyway.

  4. #4
    Transformers and other sources of QRM (ham talk for electrical interference) is what is completely killing AM radio. It is deliberate.
    Host on Rowan Radio 89.7 WGLS-FM

    Radio DX'er- using Grundig Sat. 750, Tecsun PL-880

  5. #5
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    Quote Originally Posted by radiodx10 View Post
    Transformers and other sources of QRM (ham talk for electrical interference) is what is completely killing AM radio. It is deliberate.
    The main sources of interference are things like any CPU that is not protected / shielded, the power supplies we know as "wall warts", dimmers on electric lights, the circuitry in some LED bulbs, along with more traditional things like fluorescent lights, some electric motors switches and contacts, power line leakage across dirty insulators, etc.

    None of which is deliberate....
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  6. #6
    My inexact science of just driving around seems o indicate that the worst offender to the AM band is outdoor fluorescent lighting (as in shopping malls, etc). I used to live near 12KV transmission lines and they would produce a low frequency hum occasionally but would not blot out the signal as does lighting. My toaster does not seem to be a culprit either.
    Illegitimi non carborundum

  7. #7
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    Quote Originally Posted by landtuna View Post
    My inexact science of just driving around seems o indicate that the worst offender to the AM band is outdoor fluorescent lighting (as in shopping malls, etc). I used to live near 12KV transmission lines and they would produce a low frequency hum occasionally but would not blot out the signal as does lighting. My toaster does not seem to be a culprit either.
    In the desert, leaky power lines can be a major source of noise. As dust cakes on insulators, a path to ground of a high resistance and intermittent nature is established. Electricity arcs across particles looking for a path to ground, and the sparks are like little spark-gap transmitters.

    Electric companies used to spray wash insulators regularly. I have not seen that happen for many, many years.

    Mall lighting is generally not fluorescent. Older ones are Mercury Vapor, and today's approved outdoor lighting is Sodium. M/V lamps are very RF-noisy. Old Mercury Vapor lamps are still quite prevalent.

    CFLs are tiny Mercury Vapor lamps. Depending on the internal components (the built in "ballast") they can be moderately to wildly noisy on AM.
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  8. #8
    Quote Originally Posted by DavidEduardo View Post


    Mall lighting is generally not fluorescent. Older ones are Mercury Vapor, and today's approved outdoor lighting is Sodium. M/V lamps are very RF-noisy. Old Mercury Vapor lamps are still quite prevalent.
    I was referring to the lighting used on storefronts and in windows, not the parking lot lamps.
    Illegitimi non carborundum

  9. #9
    Quote Originally Posted by doowopfan View Post
    I put on KYW when I got up this morning, as I do almost every morning, only to find it completely unlistenable. I am in South Philadelphia and there is some horrible reverberating electrical interference blowing almost the entire AM band off the air. The only stations getting through are 610 and 990. I called KYW's news room and a pleasant fellow who answered the phone said he would report it to the engineer, but that they had no other calls. I tried multiple radios. Anyone else have this happen this morning? Any thoughts as to what would be strong enough to blow almost an entire band off the air? I've never seen this happen before.
    Are you listening in your home on a portable radio or home stereo system? If a portable radio that operates from battery, try unplugging the radio and try listening on battery. If the noise is reduced considerably on battery, you probably have a switching power supply somewhere in your home that is introducing broadband noise down the neutral buss in your home. Switching power supplies are everywhere: Computers, computer monitors, TV sets, cordless phones, and LED lights. Try going around your home and turn things off one at a time before checking outside for the noise source.

  10. #10
    Thank you all for the interesting information. I was using a simple clock radio that is sitting on top of my refirgerator in the kitchen. I've had it in the same spot for years with no issue. I think the issue is a bad transformer in the neighborhood. I tried walking around with a battery-powered transistor and the hum gets worse when I point the radio out of my side kitchen window toward due east. It is a reverberating low frequency hum that sounds like whur whur whur whur. It goes away when I turn the opposite direction.

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