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Thread: 5.8 GHz helical DIY antenna cable

  1. #1
    Navigator schebb's Avatar
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    5.8 GHz helical DIY antenna cable

    Folks,

    Have built a fairly nice 5 turn helical antenna for 5.8 GHz. Would like to finish it with stuff I have in shop. Two questions:

    1. Can the cable from a D-link 2.4 GHz wifi antenna complete with SMA connector be used with 5.8 GHz?
    2. Can it be left at its 6 foot length?

    Seems like all home made antennas have very short cables on them. Thanks.

    Steve

  2. #2
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    I don't know the answer to your first question, but I do know that you can't leave it at 6ft. That is too long for such a high frequency. At 5.8GHz it should only be 2 or 3 inches, otherwise you will have big losses.

  3. #3
    Team Fat Duck Mechnan's Avatar
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    the shorter the better.
    How many engineers does it take to change a light bulb?
    3. One to hold the light bulb and two to turn the ladder.

  4. #4
    KK4IRW MASHTON1138's Avatar
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    Ideally for 5G8 you want between 2 and 5 inches in length, longer lengths will depend on the rating of the cable. On most more than 6 to 8 inches is not advisable as they are normally rated only to 3GHz.

    Post a picture of the cable you are talking about. Also if there is writing printed on it tell us what it says so we can help you find the specs of that particular cable.
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  5. #5
    Navigator schebb's Avatar
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    Click image for larger version

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    Hope there is a photo showing here. This is the cable and connector I want to rob from a 2.4 GHz wifi antenna for my DIY 5.8 GZhz helical. No writing on the cable. Is there a chance this cable would work for me? Thanks

    Steve

  6. #6
    Team Fat Duck Mechnan's Avatar
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    Should work but like most coax cables that don't have air as dielectricum and cost 100$ per meter it is propably only rated to 3GHz so try to keep it short.
    Plus make shure the cable has the same SMA plug as the tx (rp or normal)
    How many engineers does it take to change a light bulb?
    3. One to hold the light bulb and two to turn the ladder.

  7. #7
    Engineer for Jesus Christ IBCrazy's Avatar
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    That cable looks ok to use. Just cut it to 12" or less and you will be ok.

    -Alex
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  8. #8
    Navigator schebb's Avatar
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    Thank you all very much. I will try this cable and post results in future.

    Steve

  9. #9
    Navigator schebb's Avatar
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    Look like it should work? See any things that could be changed for the better?

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    Thanks.

    Steve

  10. #10
    Engineer for Jesus Christ IBCrazy's Avatar
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    Steve,

    My initial thought is your first turn is a bit too close to the reflector for the size of wire you are using. I would highly suggest tuning it with a range test of some sort. Put a few houses or something between the transmitter and receiver and play with that first turn. You might even find a full 1/2 turn close to the reflector tunes it in perfectly. It's not too hard to do, but it's not easy either.

    Other than that, everything looks good. Let us know how you like it.

    -Alex
    If it is broken, fix it. if it isn't broken, I'll soon fix that.

    videoaerialsystems.com - Performance video piloting

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