simple 2.4GHz antenna

Discussion in 'General Electronics Chat' started by bug13, Nov 30, 2014.

  1. bug13

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    Feb 13, 2012
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  2. MikeML

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  3. djsfantasi

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    Do you plan on making it as your only option? Since your an RF and antenna newbie, maybe buy an antenna.
    A quick search shows many commercial solutions for an antenna for you, such as this one.
    Shipping from the US is likely prohibitive, so I supply that link only as an idea.
    I don't know if you can get one locally, but that (and a similar) antenna is between USD 2.75 and 5.00
     
  4. bug13

    Thread Starter Well-Known Member

    Feb 13, 2012
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    Hi djsfantasi

    I am open to any suggestion, I understand that I don't have RF and antenna knowledge. I will buy one from supplier if I have to, but If I can connect something I have now to just test it, that will be great. My goal is to get it good enough to talk to each other and do some current tests.

    So If I get one from a supplier, can I just solder a 50 ohms coax to the antenna and my little module?
     
  5. bug13

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    I am hoping to get something working with a couple wires/coax, something good enough to just get them go talk. I don't mind if only have a couple of meters range.
     
  6. GopherT

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    How about picking up a used 2.4GHz WiFi router and pulling the antenna off of that?
     
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  7. Lestraveled

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    The wavelength (in air) of 2.4 GHz is 4.92 inches. A quarter wavelength is 1.24 inches. Take a piece of coax and cut the shield back 1.24 inches and you are done.
     
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  8. KJ6EAD

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    There are lots of instructions online for making improvised 2.4 GHz antennas from coax cable, tubing, cans and other junk. You'll probably get enough range and not damage anything by removing the shielding from 12.5 cm of coax center conductor.

    Edit: This would make a rough full wave antenna. Les has given you the 1/4 wave version above.
     
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  9. bug13

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    Good idea, I will if I can find one, thanks!

    Just to confirm, do you mean something like this??
    [​IMG]
     
  10. bug13

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    BTW, what is the different between using an 1/4 wave, 1/2 wave or full wave antenna?

    Thanks!
     
  11. KJ6EAD

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    Yes and read the information in MikeML's Linx link for the answer to the second question.
     
    Last edited: Jun 3, 2015
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  12. MikeML

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    No. It should look like this:

    [​IMG]

    [​IMG]


    The coax shield braid is folded back along the outside of the vinyl. The sleeve is not connected at the bottom end. You can leave the inside insulator on the whip portion. The dimensions are a few inches, not 8ft, which would be for the 28MHz amateur band...
     
    Last edited: Dec 1, 2014
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  13. Lestraveled

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    Putting metal close to a 2.4 GHz antenna will turn a great SWR into a very bad SWR. So, the transmitters in the 2.4 GHz devices have to be very fault tolerant when it comes to SWR. Building a temporary test antenna should be a pretty casual exercise. I say that any of the above examples will work fine for in-shop testing. Don't worry about exact measurements, you would need a network analyzer to get it perfect.
     
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  14. bertus

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  15. Lestraveled

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    Bertus
    Excellent resource site for bug13's project. Very good find.

    Bug13 - suggest you look at "antenna construction" on the page bertus linked to. Lots of good stuff.
     
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  16. bug13

    Thread Starter Well-Known Member

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    You often refer to this educypedia website, I think I need to book mark this, thanks a lot!

    Will do, thanks for your help!
     
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