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Thread: antenna tuning

  1. #1
    SK Member 8/11/2015
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    antenna tuning

    I finally got around to checking swr on my Inverted v fan dipole antenna.On the 10 meter segment the swr is 1:3 can't check the 40 meter on this meter as it's for CB.Any ideas on how I should go about lowering it?

  2. #2
    Pope Carlo l NQ6U's Avatar
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    Unfortunately, we need a little more data. Without knowing the antenna's resonant frequency, it's hard to give any advice. However, that CB meter should be okay across the bands as long as you keep the wattage in low.
    All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.

  3. #3
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    The 10 meter is cut for 28.400 MHz and the 40 meter for 7.075 hHz.

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    1.3:1 is acceptable and that CB meter should be pretty accurate all the way down to 80 or even 160 meters. It's going up in frequency that would be a problem.

  5. #5
    Pope Carlo l NQ6U's Avatar
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    Quote Originally Posted by N2KKM View Post
    1.3:1 is acceptable and that CB meter should be pretty accurate all the way down to 80 or even 160 meters. It's going up in frequency that would be a problem.
    He said 1:3, though, that's pretty high. Craig, I figure your antenna should be about 16' 6" long overall, is that what you have there? And how are you feeding it?
    All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.

  6. #6
    Whacker Knot WØTKX's Avatar
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    1.3 is a high swr? That's about a 2% power loss. No big deal. Even with a 4 watt output QRP radio ( ;) ) that's a loss of approx .1 watt. The coax itself probably has more loss. And at a 100 watts or so, no big deal. Check your SWR with the CB meter, it will work just fine.

    If you're gonna get that fussy, I'd suggest some magic (note the credits at the bottom ):

    Last edited by WØTKX; 04-21-2012 at 05:35 PM.
    "Where would we be without the agitators of the world to attach the electrodes
    of knowledge to the nipples of ignorance?" ~ Professor "Dick" Soloman



  7. #7
    Pope Carlo l NQ6U's Avatar
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    Quote Originally Posted by WØTKX View Post
    1.3 is a high swr? That's about a 2% power loss. No big deal.
    True, but he said 1:3, not 1.3.
    All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.

  8. #8
    Whacker Knot WØTKX's Avatar
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    OK, my bad. I read it wrong. Unless he's running a pi-network tank output (tubular style) that's not good.
    "Where would we be without the agitators of the world to attach the electrodes
    of knowledge to the nipples of ignorance?" ~ Professor "Dick" Soloman



  9. #9
    SK Member 8/11/2015
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    The antenna is 16'6" but I used insulated wire and left about 6" more to wrap around the insulator so It might be a little too long.and I may have stated the swr reading wrong the meter swings up to the 3 mark on transmit.

  10. #10
    Pope Carlo l NQ6U's Avatar
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    Yeah, it sounds like it probably is too long. Using insulated wire has the effect of lengthening the antenna electrically, for one thing. Better that than it being too short, though, because it's a lot easier to fix. Just start clipping the wire at each end maybe 1/4"-1/2" at a time and check the SWR after each trim.
    Last edited by NQ6U; 04-21-2012 at 06:04 PM.
    All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.

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