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AM Radio signal IS sounding from my wall heater

  1. May 22, 2015 #1
    I am a video and sound engineer. There is clearly AM radio coming from my wall heater.
    An earlier thread on this topic discussed the possibilities but ultimately left the subject with an assumed crazy old lady's false perception. I assure you this is happening.
    There is a 50,000W AM station (6x 150' antennae) within a half mile and interference from this station is pronounced in the area. My speakers and recording equipment are useless here. Now the radio is clearly audible out of the wall heater. I've attempted to ground it better, shield it with sheet metal, disconnect all the wires, to no avail.
    The incessant RF bombardment is a concern but the consistent annoyance of hearing the unwanted radio all night is truly horrible.
    The wall heater started acting as a radio receiver around the same time we had solar panels installed on the roof. Maybe the panels/added wires are adding to the building's electrical load and exacerbating the already insufficient grounding? Help please!
  2. jcsd
  3. May 22, 2015 #2
    Is it possible to modify the heater?
    Sound coming from the heater means some part of the unit must be vibrating. Can you disassemble the heater and add support and/or additional attachment points for the vibrating component so that it no longer vibrates at audible levels.

    Note: Only do this if you are completely sure you will not not turn the heater into a fire hazard.

    Edit: does the heater sound at all times or only when turned on?
    Last edited: May 22, 2015
  4. May 22, 2015 #3


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    welcome to PF
    living that close to such a high RF field can often cause weird probs like that

    If it happens only when the unit is powered, there's obviously something in the heater that is producing a diode action and demodulating the RF to audio
    If happens when power is also off, then its possible that 2 joining sections of the metal casing have small bare spots and are acting like a diode and rectifying the RF .... just like an old wire thread and a galena crystal

    what sort of heater is it ? split cycle aircon that can supply hot and cold ( winter/summer) ?
    or something much more basic ?
  5. May 22, 2015 #4


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    This caused a few problems in WW2 when the BBC started broadcasting messages to Europe in German. My father told a story of a pub landlord that heard German voices coming from a chimney and thought someone was on his roof.
  6. May 22, 2015 #5


    Staff: Mentor

    mrspeedybob gave you the most practical advice: find the part that is vibrating rather than trrying to do something electrically. Locate the source of the sound and use something like a styrofoam kernel from packaging material to stop the vibration. Make sure that the location doesn't get so hot as to melt the foam and make sure the heater is unplugged before putting your hand inside.. A cheap stethoscope (less than $5 on Ebay) is an excellent tool to accurately localize a sound.

    The effects of nearby radio towers can be bizarre. I once live aboard my boat within 1/4 mile of the Radio Marti Voice of America transmitters in Marathon Florida. It interferes with radios, phones, and computers. LED lighting flickers even when the power is turned off. Galvanic corrosion is accelerated. There are even reports that nearby residents mysteriously discover that they can speak Spanish :wink:
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