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simple 433mhz antennas?

Discussion in 'General Electronics Chat' started by NleahciM, Jun 17, 2005.

  1. NleahciM

    NleahciM New Member

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    Hi - can anybody give me any advice on how to make a very simple 433 Mhz antenna? Could a specific length of wire work? Or what about an antenna that's actually a trace on a pcb? Sorry I'm horrible when it comes to RF :eek:
     
  2. Roboticinfo

    Roboticinfo New Member

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    reply

    What are you trying todo?

    I mean what type of project are you doing?
     
  3. NleahciM

    NleahciM New Member

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    Re: reply

    I'm making a remote control for my outside lights. The only thing not designed is the antennas - everything else has been designed and tested. I've just been using short pieces of wires for antennas and the range seems to be pretty good, amazingly.
     
  4. dave

    Dave New Member

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  5. Roboticinfo

    Roboticinfo New Member

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    Any antenna should work fine but I would recommend a antenna off of a cordless phone like a 900mhz
    depending were you bought your tx/rx
    it could go as far as 500 feet.
     
  6. DirtyLude

    DirtyLude Well-Known Member

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    Do a search on Digikey for '433mhz antenna'. I tried making my own for a while and dealt with tuning problems. I use the linx 1/4 wave whips, now. For $2.00, it's hard to justify making your own, and they look pretty professional, too.

    You can see what it looks like, here:
    http://www.higginstribe.com/gallery/watercool/index.php?image=controller02.jpg

    If you want to go cheaper, they even have some cheezy helical coils for under $1.00.
     
  7. Roboticinfo

    Roboticinfo New Member

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    Didn't those antennas cost $10.00?

    Anyway for stylish antennas


    http://www.antennafactor.com/index.php?section=products

    go to this website.

    It is owned by linx Technologies
    And they have a variety of antennas.

    But the antennas from cordless phones are just as stylish and are good in range.
     
  8. chiba

    chiba New Member

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  9. Roboticinfo

    Roboticinfo New Member

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    That is two feet are you nuts!


    But cool calculator though
     
  10. JimB

    JimB Super Moderator Most Helpful Member

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    A simple monopole antenna is a quarter wavelength long, only six inches.

    JimB
     
  11. mechie

    mechie New Member

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    Re: reply

    Bad advice :!:

    You need an aerial that is at least close to the right size, impedance and design for your chosen frequency and task (directional/omni/...)

    Start by looking at http://www.antentop.bel.ru/ for a directional
    Or http://www.lprs.co.uk/pdf_directory/2386mylprs1110799793er-data-sheet-v2.pdf page 16 of the datasheet gives a bit of info on wire and pcb track aerials --- I'm using these little transcievers at the minute, playing with a 16.4cm monopole on a portable keyboard and a centre-fed dipole (about 4 times the above) for a remote control system - it works for me !
     
  12. Roboticinfo

    Roboticinfo New Member

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    Mechie I use cordless phone antennas for my projects that use those 433mhz tx/rx modules and I get a good range.

    Not bad advice

    Good advice
     
  13. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    As already suggested, a 1/4 wave whip is only short, and VERY easy to calculate - but even easier, read the datasheet for the RF modules you use, they generally give one or two exact aerial dimensions - particularly as the aerial is an important part of the licence free conditions!.
     
  14. NleahciM

    NleahciM New Member

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    The datasheet gave no information on this whatsoever. I think they said that a quarter wave antenna would be a good idea - but they gave no dimensions or anything like that.
     
  15. NleahciM

    NleahciM New Member

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    awesome - I'll start it out with that as it's by far the simplest solution. Thanks!
     
  16. Roboticinfo

    Roboticinfo New Member

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    But you would need two feet of wire!
     
  17. DirtyLude

    DirtyLude Well-Known Member

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    Re: reply

    I specificly said in the post that they were $2.00.

    If you went to digikey and did the search I suggested, you would have seen that the antennas that came up are actually the Linx line and to be exact, the Linx 1/4 wave whip that I show in the picture is $2.03, USD.
     
  18. Roboticinfo

    Roboticinfo New Member

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    I know you said that
    I accentdently forgot to put didn't they used to be $10.00 dollars.
     
  19. chiba

    chiba New Member

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    Hmm, i calculated a 1/4 wave antenna @ 433MHz to about:

    0.56788167205542725173210161662818 ft

    The only way i could get a result of "2 feet" was to take my shoes off then count :)
     
  20. Roboticinfo

    Roboticinfo New Member

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    Ohh I did the full length

    not 1/4
     
  21. NleahciM

    NleahciM New Member

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    Re: reply

    A quarter wave (6.5") wouldn't work? Actually for the receiver 2 feet isn't a problem at all - but for the transmitter it would be.
     

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