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Thread: Antenna and power

  1. #11
    La Rata Del Desierto K7SGJ's Avatar
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    Quote Originally Posted by koØm View Post
    Waiting...waiting....waiting; isn't anyone going to tell him that doubling his input power equals a 3 dB increase to the antenna and, that the 3 dB increase in his signal would *probably* not make a difference on the receiving end.

    Maybe I'm wrong about that, maybe 3 dB gain would make a difference EME or Sat-Comms, feel free to edify me.

    .

    ETA: Doubling you watts is not the same as doubling the length of your pecker; hard to get that concept over to the CB crowd!
    I never thought of a 3db gain in pecker length. (other than from at rest to attention) Interesting concept.
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  2. #12
    Master Navigator koØm's Avatar
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    Quote Originally Posted by kk4fpx View Post
    The Mirage is the B 3030 G. It's not listed on their site. It says 30 in 300 out. I was getting almost 100 out with a 5 watt ht and I'm getting 300 out with 25 in, measured with two different meters into a home made Egg beater antenna.
    146-4s.jpg

    A gamma match is usually a variable capacitance device; the difference between a 2Kw gamma match and a 10Kw gamma match was the thickness in the dielectric insulator. Build yourself a heavier gamma match with large components.

    http://arrowantennas.com/solid/146-4s.html

    .


  3. #13
    Whacker Knot WØTKX's Avatar
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    Mel and Kelli have great ideas.

    True, the doubling of power (from 150 to 300) isn't gonna do much at all. However, he's stuck with the 300 watts output because of the radio. For now. How many feet of RG-58 would it take to attenuate... ;)

    That Arrow antenna has a claimed gain of 9.7dBi. :chin: Even if a bit of a high claim, that's a big help. Typical 10 element Yagi instead would be what, maybe 11-13dBi? Arrow antennas are pretty damn good, so that is decent. all by itself.

    Another Arrow Yagi "stacked" with a power divider is "yet another" 3dB, and would split that 300 watts. No more power issues, and gulp, more gain. Of course a phasing harness would split the power and give even more gain if carefully designed.

    But hell, the combination of 150 watts and the Arrow should do quite well.
    Two of those Arrows with 300 watts would hurt people. Eh?

    Always go for MOAR POWER (gain)!

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  4. #14
    SK Member 8/11/2015
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    Okay all I'll not try the 300 watts. Thanks for the input.

  5. #15
    La Rata Del Desierto K7SGJ's Avatar
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    Quote Originally Posted by kk4fpx View Post
    Okay all I'll not try the 300 watts. Thanks for the input.

    A wise choice. Just to give you an idea of what can happen, scientists had a 150 watt tracker on a bald eagle. One of them briefly ran 300 watts, and...........



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    A clear conscience is usually a sign of a bad memory

    RIP ALBI-W3MIV RIP RUSS-W5RB RIP BOB-VK3ZL





  6. #16
    Orca Whisperer PA5COR's Avatar
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    A well designed 10 element yagi can do 10 dBd my 11 element Flexa yagi states 12.4 dBd
    9.7 dBi will be 6 dBd.
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  7. #17
    Master Navigator wa6mhz's Avatar
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    just put a 50 foot run of RG-58 coax between the radio and the amp. U will lose enough dogbones to lower your power output way way down! 'Course Ur RX will be numb then too! (by about the same DB!)
    Seriously, I doubt the antenna would be harmed, if U have some decent coax going to it from the amp. RG-8X will probably warm up though I have run a KILLERWATT through mine. Those antennas are probably way underrated, as they never expected anyone to run high power through them.
    I would bet U could run a full 1500W into it and it would work just fine!

    Nothing on the antenna is really going to break down. The gamma match or T match is probably same the HIGH power antennas have, it is a pretty standard design. I know the tower mounted antennas are good for 1500W, but the arrow is a hand held antennna. Again no one expected any one to be QRO into a hand held antenna!
    Last edited by wa6mhz; 03-25-2015 at 03:35 PM.

  8. #18
    Master Navigator wa6mhz's Avatar
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    After examining that link, I cannot see why it wouldn't handle 300W EASILY! It' not the hand held antenna I was thinking of.

  9. #19
    Master Navigator wa6mhz's Avatar
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    Quote Originally Posted by K7SGJ View Post
    A wise choice. Just to give you an idea of what can happen, scientists had a 150 watt tracker on a bald eagle. One of them briefly ran 300 watts, and...........



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    I wouldn't wanna PISS THAT BEE OFF!!

  10. #20
    Island Godfather NA4BH's Avatar
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    Again no one expected any one to be QRO into a hand held antenna!

    You can do it once

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    The best ones are opened with a smile"

    NA4BH '15

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