I hope to design 2.4 Ghz Omni Antenna

Discussion in 'Wireless & RF Design' started by srmed2000, Mar 11, 2009.

  1. srmed2000

    Thread Starter New Member

    Jun 23, 2008
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  2. wr8y

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    Sep 16, 2008
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    How are you going to get 15 DB gain out out of an omnidirectional antenna? :eek:
     
  3. srmed2000

    Thread Starter New Member

    Jun 23, 2008
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  4. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    It's definitely going to be a collinear of some sort!

    Eric
     
  5. wr8y

    Active Member

    Sep 16, 2008
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    How narrow would the pattern have to be to get 15 dB in an OMNI?

    Gain comes from concentrating radiation within a pattern (and taking radiation from outside the desired pattern). Just how far can we take this process and develop gain while keeping an omnidirectional pattern?
     
  6. wr8y

    Active Member

    Sep 16, 2008
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    :)
    The CLAIM is 9 dB. Most I have seen in a quality omni antenna is 7.5 dBd (so, maybe 9 dBi is possible - but not 15 dBd or dBi. I will believe otherwise when I see it.)
     
  7. KL7AJ

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    Nov 4, 2008
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    Some UHF TV broadcast antennas (slotted ring or panel) run that high a gain. But they are BIG.

    Eric
     
  8. wr8y

    Active Member

    Sep 16, 2008
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    Man, they are squeezing the pattern a LOT, ain't they?

    I have not had college physics yet, that will come late this year or next - I was just wondering how much you'd need to concentrate the pattern to get 15 dB(i or d) gain...

    I have a friend who is an associate engineer at http://www.munn-reese.com/
    I'll email him. (He's their AM directional guy, too. Does some transmitter work, but mostly AM directional arrays. But they don't go to Alaska - mostly midwest and upper great plains.)
     
  9. KL7AJ

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    This became quite common with the advent of HDTV. Most stations, if they're at any altitude, have to use some downward beam tilt, so the squashed pattern doesn't just skip over the top of the coverage area! But this is the only way they can get the required EFP, since it's SO expensive to generate any real power with DTV transmitters.

    eric
     
  10. RAH1379

    Well-Known Member

    Dec 13, 2005
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    It is possible, antennas at that high of frequency are small enough to stack several into an array, two that come to mind for omni-directional patterns would be a vertical colinear array, or stacked halos.
     
    Last edited: Apr 15, 2009
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