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Carolina Windom without vertical radiator?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by M6BTW, Jan 26, 2011.

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  1. M6BTW

    M6BTW Ham Member QRZ Page

    Hello,

    I have bought a Carolina Windom 40+ which has a 18ft (5.5m) vertical radiator between balun and choke. I didn't choose this model it was the only one availabe at store.

    Edges of the antenna are at about 33ft (10m) height but due terrain slope aspect and balun/feeder/choke weights I can't have the choke more than about 1ft (0.4m) off the ground. I think I have two choices, one to trim the radiator to a different shorten length or to remove it at all. I am not realy interested in other bands than 40m and by removing the vertical part of it I think I will end up with a classic windom antenna.

    If I remove choke do you think I'll have power radiated in feeder cable causing RFI? Better idea will be to keep choke and put a short cable between, if so what suggested length?

    Please advise.

    Thanks,
    Cornel
     

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    Last edited: Jan 26, 2011
  2. W5DXP

    W5DXP Ham Member QRZ Page

    If you remove the choke, you will have considerable common-mode current all the way to the shack. You could try shortening the vertical section even to the point of moving the choke very close to the balun. That would result in a 4:1 balun and a 1:1 choke in series at the antenna feedpoint.

    Personally, I would turn the OCF into a center-fed dipole and feed it with ladder-line which doesn't radiate much when the currents are balanced. The balun/choke combination could be moved back close to the tuner.
     
  3. W2BLC

    W2BLC Ham Member QRZ Page

    A couple of ways to go

    I have an OCF with a combo 4:1 and 1:1 balun in a single box at the feed point. The latter is to keep RF off the feedline. The antenna works well on 80 thru 10 with my rig's internal tuner.

    I prefer coax, however a center fed antenna using parallel feedline will work well over all the bands also. If you want to use coax, then place a 4:1 balun outside and run coax from the tuner to it - and parallel line from it to the antenna.

    Both antenna systems arrive at the same place and are pretty much equal in performance. I have tried both when testing many years ago - using the old A/B method. Only 80 and 40 were tested - I don't do DX or contests.

    There is no reason you cannot shorten the "vertical radiator" to whatever length you wish. I doubt if you will notice any real difference in performance. I proved this by running a Carolina with my OCF and doing the A/B thing. Again, only 80 and 40 were tested.
     
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