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Thread: External Antenna Question

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    Question External Antenna Question

    Hi all.

    My brother has a truck and has a external antenna for his Nokia mobile hands-free kit (the type that attaches to the front windscreen). Is there any reason that this antenna cannot be used for his Navman? He no longer uses a Nokia phone and his new phone has no problems with coverage so we where thinking that the antenna could be used to boost the signal strength of the Navman.

    Thanks in advance.



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    i think the connectors are universal it should connect if not you should be able to buy a adapter and yes it will work on the navman
    IF IT DONT WORK USE A BIGGER HAMMER

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    Most GPS antennas (external to navigators, handheld GPS) have a preamplifier in them which is powered by the unit via the cable. If the antenna you connect has a DC short to ground you might break something in the unit by shorting its DC supply...it might be current limited but ...risky !

    External GPS antennas are sometimes described as "active antennas" - in other words they have a built-in preamplifier.

    EDIT....here's a bit on adding an external antenna, or you could just buy such a device off EBAY etc.



    EDIT AGAIN ....if you are really keen, and enjoy a bit of do-it-yourself, you can make your own antenna out of bits and pieces..

    Last edited by bulbous; 27-02-08 at 08:32 PM.

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    Quote Originally Posted by bulbous View Post
    If the antenna you connect has a DC short to ground you might break something in the unit by shorting its DC supply...it might be current limited but ...risky !
    If the antenna has a DC short then it wouldn't matter what device you connect to it, wouldn't it still damage it?

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    Quote Originally Posted by antelopeslr5000 View Post
    If the antenna has a DC short then it wouldn't matter what device you connect to it, wouldn't it still damage it?
    Absolutely not ! An antenna can be a perfect short-circuit to DC but quite resistive to Radio Frequency energy.

    Have a look at the folded dipole on a TV antenna for example, a dead-short for DC but a 300 Ohm impedance for RF.

    Many antennas present a DC short across the feeder cable, in other instances (especially at HF and MF) a Radio Frequency Choke is deliberately placed across the feedpoint to bleed off static and to assist in lightning protection.

    RF is strange stuff until you've absorbed enough....or too much....or something. .

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