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Portable radio in train, bad reception

  1. Apr 27, 2009 #1

    I travel by train nearly every day, and I am using a crappy portable radio connected to my phone (it's just a very small radio receiver built into the earphones) to listen to the radio during the journey.

    I can't help but noticing two effects, one that can probably be explained pretty easily, but one that I cannot explain:

    1. While the journey progresses, the reception (is that the correct word?) becomes worse and worse. Sometimes it is worse than other times; I may hear no noise whatsoever on same days, and only noise on other days.
    I thought this could be explained easily because I am travelling further away from the radio broadcaster near my area, and I may have to change the frequency to get a better reception.
    However, once I get off the train and have left the station, the reception is usually back to normal!

    2. When the train starts braking when it arrives at a station, and when I am close to either end of the train cart, my reception is suddenly completely gone. It is not a coincidence; the trains engines sound like some electrical whine, and when they start to brake it is clearly audible by the change in engine sound. The radio reception is gone the instant the train starts braking.
    If I am in the middle of the train cart when the braking occurs, the reception loss is not so obvious, although it is still present.

    I am merely wondering, what can cause this? I don't know if the train's engines are electric or not (they sound like it though), maybe they cause some interference somehow?
    I can't understand the relevance of the braking though, nor the relevance of my position inside the train cart.

    Finally, is there anything I can do about this except buy a better radio receiver? It's not very important of course, but since I was wondering about this I decided to ask. The noise does get very annoying and I'd like to listen to the radio properly...

  2. jcsd
  3. Apr 27, 2009 #2
    The noise is obviously due to electrical sparks that emit the whole range of radio waves. I am afraid you cannot get rid of it even with a better receiver. Before buying a better one, borrow one to check.

    Concerning the braking effect, I have no idea. Maybe some strong magnetic or electric field affects (tunes away) the receiver frequency?

  4. Apr 27, 2009 #3
    I like the sparks idea, but that does not explain why there is no noise for like the first 15 mins of the journey. After about 20 minutes or so the noise starts and worsens progressively.
  5. Apr 27, 2009 #4
    It may be sparks from high-voltage wires along (or close to) the train way, not only sparks from the train contacts.

    Last edited: Apr 27, 2009
  6. May 18, 2009 #5
    What kind of train are you on - a diesel electric, an all electric with overhead catenary or one with a third rail?

    Are you listening to AM or FM?
  7. May 18, 2009 #6
    Both the first and the second. I'm listening FM.
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