remote balun location

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by VK3HJV, Jun 14, 2019.

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  1. VK3HJV

    VK3HJV Ham Member QRZ Page

    Hello Ive just built a 4.1 remote balun for my horizontal loop feed with 450 ohm ladder-line and Im just wondering if there is any advantage or disadvantage were the balun should be located Its currently 1 ft above ground.

    Should i try to mount it a little higher or will it make no difference? I could go approx 10 ft from ground if needed.
     
  2. W9IQ

    W9IQ Ham Member QRZ Page

    What type of balun is it? A one core voltage balun or a two core current balun? Are you connecting coax to the balun or continuing with your 450 ohm line?

    - Glenn W9IQ
     
  3. VK3HJV

    VK3HJV Ham Member QRZ Page

    Hello Glen I have a 4.1 current balun I built from a kit, From the tuner i have aprox 8ft of RG214 coax to the balun (located just of the ground) then i have about 25ft of ladder-line fixed to the loop wire
     
  4. AI3V

    AI3V Ham Member QRZ Page

    What is the feedpoint impedance of your loop?

    You added a matching device, why?

    Rege
     
  5. AA5CT

    AA5CT Ham Member QRZ Page

    I think we need a "menu" with pictures (like at McDonalds) - this voltage/current 1/2 core stuff is getting nightmarish ..
     
  6. W9IQ

    W9IQ Ham Member QRZ Page

    T
    The purpose for using ladder line in favor of coax is to reduce the feedline losses. So you ideally should use ladder line for as much of the run as practical and connect your balun at that point to transition to coax or even directly to your tuner.

    Your antenna is not presenting a matched load for your ladder line. This means that nowhere along the length of your ladder line will there be a 450 ohm impedance. You may find that the input impedance is not a good match for your balun. In this case, you may need to extend or shorten the ladder line a bit to present a more suitable impedance to the balun.

    I asked one core or two in your balun because many manufacturers claim their one core balun is a current mode balun. There are no single core, TLT, current mode 4:1 baluns. Two cores are required.

    - Glenn W9IQ
     
  7. WB2UAQ

    WB2UAQ Ham Member QRZ Page

    Glen
    You raise a good point about a 1 core current balun vs and 2 core current balun. I believe Balun Designs has a 1 core (all windings on one core) that is supposed to be a current balun so I made up a balun with one core and experimented with winding direction and it seems to have reasonable common mode impedance for the core and number of turns I applied. Then some years ago Steve, G3TXQ brought up the need to have 2 cores for a 1:4 current balun and knowing Steve, I believe him as well. I still have the single core 1:4 balun and I'll go back and retest it but what is accepted as reality? tnx and 73
     
  8. W9IQ

    W9IQ Ham Member QRZ Page

    You will possibly find that your one core version offers some degree of CMC suppression but not to the degree that a proper current mode balun will.

    - Glenn W9IQ
     
  9. EA1DDO

    EA1DDO Ham Member QRZ Page

    One core CHOKE could be fine.
    4:1 Balun (Guanella style) needs TWO cores.

    73, Maximo
     
    KU3X likes this.
  10. AA5CT

    AA5CT Ham Member QRZ Page

    I'm wondering why, in all their infinite wisdom, why the inventors of these BALUNs didn't call them right from the beginning CURRENT or VOLTAGE baluns ...
    re: " Then some years ago Steve, G3TXQ brought up the need to have 2 cores"

    I wonder if this has more to do with stray capacitance and winding techniques than the fact they are sharing the same magnetic core; an OP up thread indicated good results at one time on his project.
     

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