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4:1 current balun suggestions?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KB4MNG, Jul 27, 2021.

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  1. KB4MNG

    KB4MNG Ham Member QRZ Page

    I have a high quality balun designs 4 to 1 current balun. I would like to utilize it. The situation I have, one leg will have to go on a roof and the other leg will be able to extended out. I have a high quality palomar 1500 watt tuner. What configuration would you suggest such as wire length etc....?

    thanks for your time kb4mng
     
  2. W9IQ

    W9IQ Ham Member QRZ Page

    Can you fill in the blanks?

    To what type of antenna are you referring? What is the length, height, etc? What band of operation? What mode and how much power? What is the model number of the balun?

    - Glenn W9IQ
     
  3. KB4MNG

    KB4MNG Ham Member QRZ Page

    I think a 4114 model. ITs a high power 4 to 1 current balun. Primairly 40 meters and some 75. Height of balun would be roof level. Was hoping you could give me a configuration to start with. thanks
     
  4. WD4ELG

    WD4ELG Ham Member QRZ Page

    OCF antennas work best with 4:1 current baluns, based upon my research and experience. You can get several bands out of the one antenna...80/40/20/17/12/10. Mileage may vary with noise, since it's not a resonant antenna.
     
    KU3X likes this.
  5. K6GBW

    K6GBW Ham Member QRZ Page

    OCF Dipole is the first thing that comes to mind. The 4:1 balun work on them up to about fifty feet or so, then they usually switch to a 6:1. The only problem is the OCFD for 80 meters is pretty big (90' leg and a 45' leg). Also being at roof height it's not going to get out really well unless you are courting NVIS on purpose. But hey, any antenna...
     
    WD4ELG likes this.
  6. WA7ARK

    WA7ARK Ham Member QRZ Page

    Yes
    Huh, that is news to H. Hertz and the rest of us...

    It is not symmetrical, but it is resonant...
     
    N5XH likes this.
  7. W9IQ

    W9IQ Ham Member QRZ Page

    A folded dipole is another option but for 40 and 75 together.

    - Glenn W9IQ
     
  8. WD4ELG

    WD4ELG Ham Member QRZ Page

    Of course. Apologies. Asymmetrical. Not a 50 ohm impedance (which is why we need the balun). But resonant, yes.
     
  9. WA9PND

    WA9PND XML Subscriber QRZ Page

    Lots of good info on OCFD on the web. Do realize that in addition to the 4:1 current balun, you will likely want to include a 1:1 choke on the feedline closer to the shack. An OCFD by design puts a lot of common mode currents on the feedline, and even the best of the 4:1 current baluns is not always enough.

    My OCFD is about 25' up. Tuned for 40 meters, it is fully functional without tuner on 40/20/15/10/6m. I tap at 18% as that gives me the shortest feedline back to the shack.

    https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwig7fu5nInyAhVNCM0KHQ_nAVMQFnoECAIQAw&url=https://rsars.files.wordpress.com/2013/01/k1poo-4-band-ocfd-40-20-15-10m-richard-formato-iss-1-3.pdf&usg=AOvVaw1oIZfXmercfGOaDgwJYEr5
     
    Last edited: Jul 29, 2021
  10. KB4MNG

    KB4MNG Ham Member QRZ Page

    Thanks for the info. What is the final length you come up with each leg. I understand it is hard to tune.
     

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