My first time playing with wire antennas.. how to choose a balun ?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N8MLP, Apr 2, 2020.

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  1. N8MLP

    N8MLP Ham Member QRZ Page

    I just picked up a LDG z100+ to play around with some wire antennas. I also have a 20' crappie pole on the way.

    How do I decide on a balun/unun? 1:1, 4:1, 9:1 They are cheap enough Ill probably end up get a few.

    I use a 891 and plan do try building mostly endfeds because I don't have long sections of feed line, yet.
     
  2. WL7PM

    WL7PM Ham Member QRZ Page

    You have autotuner.... This device will impedance match your coaxial feedline to your RADIATING antenna wire. No " Balun " is required, nor desirable.
     
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    An end-fed doesn't use a balun, it uses a unun (unbalanced to unbalanced), and the "ratio" depends entirely on the antenna length in wavelengths.

    For an end-fed quarter-wave, 1:1. For an end-fed half-wave, about 49:1. For other lengths, something between those. This is "wavelength" dependent.
     
    WB5YUZ likes this.
  4. W9WQA

    W9WQA Ham Member QRZ Page

    many autotuners dont want to feed coax.. just one connector for wire. i use sg230. it says no coax.
    just told you all i know about that !!
     
  5. N8MLP

    N8MLP Ham Member QRZ Page

    I need a device to go from feedline to wire. I thought a balun/Unun is what does that.
     
  6. N4FZ

    N4FZ XML Subscriber QRZ Page

    You can use a Current Balun with your half wave dipole. It will reduce feed line radiation. You might not need a tuner if the dipole has a low enough SWR, SAY 1.8:1 or preferably less.
     
  7. WA7ARK

    WA7ARK Ham Member QRZ Page

    Makes a huge difference if you are building a non-resonant Marconi (which requires a good ground plane), or if you are building a resonant half-wave end-fed Hertz dipole, which doesn't require a ground connection, but might need a Common Mode choke on the coax at the "right" point in addition to a transformer.

    When using a non-resonant Marconi (wire fed against ground), the best place for the tuner is outdoors right at the antenna base. If you need to feed it with a coax run several wavelengths long and want to use an in-shack tuner, then you have to design the antenna so that the SWR is less than about 5:1, otherwise the coax losses make the antenna system a poor performer. With a remote tuner, it does the matching right at the antenna, and the coax can be much longer because the SWR on the coax is close to 1:1.
     
  8. KN6CSB

    KN6CSB Ham Member QRZ Page

    balun designs makes quality stuff, a bit pricey, but worth it for the "buy right once, cry once" type.

    read their info on this page. https://www.balundesigns.com/support-downloads/

    it really depends on what type of antenna you plan on.
     
    N5YPJ likes this.
  9. N8MLP

    N8MLP Ham Member QRZ Page

    Wow guys a lot of overwhelming info here!

    i was hopping for something simple and easy. Toss in a backpack, sling a wire in a tree or on my crappie pole. Tune and go.

    I also am not opposed to an off the shelf antenna like a Packtenna or something.
     
  10. N5YPJ

    N5YPJ QRZ Moderator QRZ Page

    The choice of balun if any depends on the type of wire antenna used. For instance I use a 2:1 current balun at the feed point of my Delta loops (there is a much cheaper alternative I'm not able to build it). For a doublet or dipole fed with ladder line my choice is a 1:1 current balun with a short run of quality coax from it to the tuner. It may be best to find the antenna that best fits your yard and wants first then look at baluns. You have an auto tuner that is a good start. :)
     
    N1LOU likes this.

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