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Wired USB devices shown to lose power due to RF interference

  1. Feb 16, 2013 #1
    I previously posted about an RF interference issue that was affecting a pair of Klipsch ProMedia 2.1 speakers here. I have since found that a neighbor living across the parking lot broadcasts transmissions of up to 2,000 Watts from his apartment, which has been the cause of this issue. I have even found a causative relationship between the broadcasts, and seemingly random power loss of wired USB devices connected to my computer. The broadcasts disable wired USB mice, so that they must be unplugged, and then plugged back into the port. This also affects the USB power connection of my iPhone, so that the phone reacts as if it has been unplugged, and then plugged back in within milliseconds.

    First off, I have a CompTIA A+ Certification, and have much experience with computers. There is no question about the soundness of the hardware and software. Secondly, questions about grounding in my apartment surfaced in response to my original post. I have tested the three pronged receptacles that my devices are plugged into with a multimeter. That testing showed ~120 volts from hot to neutral, ~120 volts from hot to ground, and no appreciable reading from neutral to ground.

    The one question for which I have been unable to discern a satisfactory answer is whether or not it would be possible to prevent interference from powerful radio broadcasts? I originally thought that grounding was supposed to be important, but it has not appeared to be meaningful. I have ferrite chokes installed on the electrical input to the amp/sub, and I have chokes installed on the output wires from the amp/sub to the speakers. The chokes have made an impact, but it seems that I do not have enough wire to accommodate the number of chokes that would be required to keep the speakers from being affected. As for the mice and iPhone, I could install chokes onto the PC electrical input plug, but it would be utterly impractical to install chokes onto the wires between the devices and the USB ports. Is there any type of shielding that I could possibly use? Are there any steps I could take on my own to prevent the interference?

    I have talked to my noisy neighbor about filters, which would seem to be the prescribed solution for issues like this that I am aware. But the conversation always turns to center around the frequency on which my devices operate. He insists that my devices must necessarily operate on the same frequency that he is broadcasting, otherwise this issue would not occur. He provided to me a set of speakers which had a higher frequency response [significantly smaller sub], that he was sure would not be affected. They were. He is now talking about elevating his antenna so that his broadcasts travel over my apartment, instead of through. I am not sure if he is thinking about this issue in the proper terms.

    This issue was nonexistent in an apartment only 1/4 mile away. But my situation is such that I will be in this apartment for some years. I am not trying to rock the boat, but the mouse issue is absolutely insufferable when I'm trying to do homework!
  2. jcsd
  3. Feb 16, 2013 #2


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    I don't know what country you are in, but operating a 2kW transmitter that causes that level of RFI is probably illegal. Since there is no problem about proving who is doing it, getting the relevant authorities to close him down should be straightforward.
  4. Feb 16, 2013 #3


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    Many years ago, my wife and I had an apartment across the street from a chiropractor that had a large radio mast attached to his house. I was getting lots of thumping noises through my stereo in the evenings until I figured out what was causing it.

    I pounded on his door, and his son told me that his father was busy talking to somebody in South Africa. I told him to get his father to the door ASAP. The jerk came to the door and suggested that I get some shielding on my "cheap" stereo. I told him that the next knock on his door might be from someone coming to confiscate his SW gear. The interference stopped right then.

    This was decades before personal computers, but my stereo gear was top-notch (probably cost a lot more than his stupid SW amp) and I had never had any problem with interference before. When the jerk's kid told me that his father was busy talking to somebody in South Africa, that nailed it. Key-coding halfway around the world (Maine, US) to SA takes some real horsepower.

    Please get some guidance about shutting this person down. He has no right to interfere with his neighbors' electronic devices.
    Last edited: Feb 16, 2013
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