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Phone antenna design

  1. Nov 24, 2009 #1
    I made the mistake of buying a cheap Chinese phone on Ebay
    (don't buy phones from Shaosan Li)
    The reception was useless and in only worked in direct line of sight of a phone tower less than 50 m away.
    With nothing to lose I pulled the back off the phone and located the internal antenna, and using the battery I jammed a loop of insulated copper wire against it.
    It now works a little better - Great outdoors but only sms indoors.
    Is there someone here that can save me weeks of trial and error and tell me the
    optimal length / thickness / material I should use to improve reception even more ?
  2. jcsd
  3. Nov 24, 2009 #2


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    Science Advisor

    Contact the seller and negotiate a return of the phone. If not, contact EBay. These sellers really don't want negative reports on EBay.

    If you really have to modify the phone, you can calculate the length of a quarter wavelength of antenna as follows:

    L = 75 / F

    Where F is the frequency. If F is 2400 MHz, the length would be 75 / 2400 meters or 3.125 cm.

    Strictly, it should be a little bit shorter than this, but if you cut a piece of wire to this length, it might be worth a try. You would have to solder it to where the existing antenna joins on.

    This might do some good, but it is only a last ditch approach. It probably won't work.
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