Radio Works Carolina Windom Balun Question

Discussion in 'Ham Radio Discussions' started by W8DNZ, Feb 26, 2019.

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  1. W8DNZ

    W8DNZ Ham Member QRZ Page

    I have a Radio Works 80LP Windom that has a defective balun (damaged in the recent wind storms). Does anyone know if this balun is a "standard" 4:1 balun, or is Jim did something special in the manufacture of this item? Jim has retired, and there is no support available now from RW.

    Thanks. . .

    Mike - W8DNZ
     
  2. K4AGO

    K4AGO Ham Member QRZ Page

    Mike, There is nothing magical about the 4:1 balun that
    Radio Works uses. Purchase one to replace the damaged one or better yet, build it yourself.

    Take a look at this link.

    https://m0ukd.com/homebrew/antennas/homemade-carolina-windom-antenna/

    73
    John
    K4AGO
     
    KA4DPO likes this.
  3. N8QZH

    N8QZH Ham Member QRZ Page

    IDK what he done, I'm thinking because he recommended a BALUN and a "line isolator" That he used a voltage balun and then a 1:1 current balun (Choke)..

    What you want is a 4:1 current balun (guanella balun). Which provides the 4:1 transformation as well as the RF choking action.
    Because the off center fed antenna is inherently unbalanced, You need the isolation of a current balun, to prevent feed line radiation / reception..
     
    WA1GXC and AF7XT like this.
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I think that would defeat the purpose of the Carolina Windom design, where the vertical coax feedline from the feedpoint down to the isolator is intended to radiate (lots of common mode current, kind of on purpose).
     
  5. KC8VWM

    KC8VWM Ham Member QRZ Page

    Perhaps this is the perfect opportunity to try out a different and better antenna design.
     
    KA4DPO and AD5HR like this.
  6. N5CM

    N5CM Ham Member QRZ Page

    ARRL Antenna Book, 23rd Edition, page 10-8, "The "Vertical Radiator" for the Carolina Windom is a 22-foot piece of RG-8X coax, with a "line isolator" (current-type choke balun) at the bottom end and a 4:1 "matching unit" (impedance transformer) at the top, The system takes advantage of the assymetry of the horizontal wires to purposely induce current onto the outer shield surface of the vertical coax section. Note that the matching unit is a voltage-type balun transformer, which purposely does not act like a common-mode choke balun."

    So, if I understand correctly, the upper balun is a 4:1 voltage balun, and the line isolator is a 1:1 choke balun.
     
    K6OJ and N5XH like this.
  7. W2AAT

    W2AAT XML Subscriber QRZ Page

    Agreed.... He should take a look at the W5GI Mystery Antenna!
     
  8. W8DNZ

    W8DNZ Ham Member QRZ Page

    Thanks all.

    The 80LP has the 22' vertical section with the line isolator at the bottom. So I agree the balun at the feedpoint should be the 4:1 voltage-type transformer.
     
  9. W8DNZ

    W8DNZ Ham Member QRZ Page

    Not an option at this time. . .
     
  10. AF7XT

    AF7XT Ham Member QRZ Page

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