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Ferrite beads block cell phone radiation?

  1. Jul 15, 2005 #1
    So how effective are these beads? Which dimensions would be optimal for radiation blockage?

    I'm understanding that the article assumes that radiation from the cellphone itself would appear to be reduced because the user has a headset and so the phone would be distant from the body. So the ferrite bead is just blocking any residual radiation that might be travelling up the headset wire?

    Thanks for your clarifications! :smile:
  2. jcsd
  3. Aug 7, 2005 #2
    How does this work?

    My understanding of cell phone radiation is that it is transmitted from the antenna, and that a hands free set would not rebroadcast that radiation. Does anyone know what the exact mechanism for hands-free transmission of radiation is?
  4. Mar 6, 2010 #3
    The headphone jack being connected to the phone's circuitry cand and does transmit radiation. If your are familiar with some phones that have FM tuners built in you will note that they require you to plug in the headphone for the radio to work. This is because the headphones or earphones act like an antenna to capture radio waves and direct them to phone.

    In the reverse manner when the phone is emitting radio waves (be it for FM radio or to communicate to the cell tower to make or receive calls) if the head phone jack is plugged in, the radio waves will travel up the head phone jack. this is not by design but non the less, this adverse affect causes the headphones to become a bidirectional antenna directing radio waves strait to the head.

    It is also not safe to put the cell phone to your head when using it. using a ferrite bead or sometimes called ferrite choke on the headphone, placed as close to the cell phone as possible is the best alternative to not using a cell phone that I have found thus far.
  5. Mar 24, 2010 #4
    May be, we sometimes exaggerate some topics too much.

    And take no notice of things like this.

    But the thing is, if any type of radiations penetrate through your body, then I wonder what exactly happens in our body during this process. There must be some kind of danger.

    I once read somewhere that if we use too much of cell phones, then our feet must have a direct contact with the earth during its use !!

    Any idea how come ? !

  6. Apr 1, 2010 #5


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    But I thought that was what has been tested so far and there's no connection to any cancers or diseases? That's why it has been approved as safe. Claiming that it is "not safe" really does require some research and proof on your part. Do you have any links to studies concerning modern cell phones where it has been shown to be unsafe? If not, how then do you come to that conclusion?
  7. Apr 1, 2010 #6


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    If the 'researcher' believes that then they must believe there is some distance at which it is safe.
    So having decided with no evidence that a phone next to your ear is dangerous, they have decided that one in your pocket is safe

    Otherwise i can come along and with the same lack of evidence say that he shouldn't use a hands free set, because the phone is still within 1m of you, you should use a Bluetooth headset and keep the phone 10m away. Although I suppose you could claim that the radiation from the Bluetooth as harmful.
  8. Apr 1, 2010 #7
    For maximum effect the bead should be placed around the antenna at its base.
  9. Apr 1, 2010 #8


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    That's false. At the wavelengths used by cell phones, their antennas work fine stand-alone.
  10. May 12, 2010 #9


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    Do you understand the general principles of how a cell phone works in the first place? A cell phone uses a radio to communicate with a tower; a handsfree set (bluetooth) is ANOTHER radio that communicates with the cell phone (using a radio at a different frequency with much lower power).

    Do you understand the difference between electromagnetic radiation like radio waves and ionizing radiation like X-rays and gamma-rays? I'll give you a hint- one can give you cancer, and the other has no measurable effect on you at all (that has yet been proven anyway).

    A sweeping generalization like "radiation is dangerous" is meaningless, and driven by undereducation in the subject.

    Let's just say that's excellent proof that you can't believe everything you read. Especially on the internet.
  11. Jun 20, 2010 #10
    Beads increase the impedance of the wire that threads through them at RF frequencies. Nowdays handsfree is going Bluetooth so this is becoming irrelevant.
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