Ham Talk Live! Episode 248 - Building the Big Ugly Balun

Discussion in 'Amateur Radio News' started by WB9VPG, Feb 24, 2021.

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  1. WB9VPG

    WB9VPG XML Subscriber QRZ Page

    The "big ugly" might be a famous 22 ounce hamburger in Indiana, but this week on Ham Talk Live! we're talking big ugly baluns! John Portune, W6NBC will be on the show to take your questions about building an ugly (coiled coax) balun and why they are useful.

    Tune into Ham Talk Live! Thursday night at 9 pm EST (Friday 0200Z) by going to hamtalklive.com. When the audio player indicates LIVE, just hit the play button!

    If you miss the show live, you can listen on demand anytime also at hamtalklive.com; or a podcast version is on nearly all podcast sites a few minutes after the live show is over. Some sites include Apple Podcasts, Google Podcasts, Spotify, SoundCloud, Stitcher, Spreaker, TuneIn, Vurbl, and iHeart Podcasts; and it's also available on YouTube.

    A replay is also broadcast on WTWW 5085 AM shortwave near Nashville, TN on Saturday nights at approximately 3:30 pm Eastern.

    Be sure to CALL in with your questions and comments by calling 859-982-7373 live during the call-in segment of the show. You can also tweet your questions before or during the show to @HamTalkLive.

    bigugly.jpg w6nbc.jpg
     
    M1WML likes this.
  2. K2WPM

    K2WPM XML Subscriber QRZ Page

    Thought this was very interesting, thanks for the article John.
    I also really liked John's experiments with ladder line. w6nbc.com/articles/openwireline.pdf
    Be aware of the QRZ controversy over John's article however ... the thread is up to six pages!
    But coax-wound baluns aren't going anywhere; just search the antenna forum using the word "ugly."
    For ugly balun.
     
    M1WML and R6AD like this.
  3. KM1H

    KM1H Ham Member QRZ Page

    Id love to see a NanoVNA (or any other plot) of that thing as they have a reputation of being very narrowband.

    Carl
     
    M1WML and AK5B like this.
  4. W1YW

    W1YW Ham Member QRZ Page

    My preference would be to see this coil balun on CPVC rather than PVC, at least at HF.

    Nowadays one can VNA-measure the insertion loss of such coil baluns by a S12 'thru' normalized via a wee short length of hardline for the 'normalized' length. Anyone know its insertion loss at various freqs:)?

    Anyway, the objective of the Big and Ugly is to get folks to build stuff, always a welcome and valuable opportunity.

    I always enjoy frying concatenated choke baluns myself;-) Many years ago, my neighbor called the cops because such ferrite choke baluns are built into PVC pipe and look like pipe bombs... I asked the cop: what was I supposed to be blowing up... a bush in my backyard?
     
    M1WML, PU2OZT and AK5B like this.
  5. K6MIT

    K6MIT Ham Member QRZ Page

    ITS NOT A BALUN why do people keep calling these a balun ? a balun matches two different impadances.
    all this is is a rf choke..doesnt match anything...just stops rf from traveling on the shield of the coax...
    and even then, its only effective on the design freq of the choke and useless on all other freqs.
     
    VA7UO, KG0BK, M1WML and 5 others like this.
  6. PA0MHS

    PA0MHS XML Subscriber QRZ Page

    Wrong. A balun matches a balanced entity to an unbalanced entity. And that's exactly what this thing can do. And technically speaking, this is a transmission line transformer with a 1:1 ratio. And if you ground one end, the other end becomes symmetrical with respect to ground. And it presents a high impedance to common mode currents flowing through both the center conductor and the shield.
     
    K9EZ, N8TCQ, M1WML and 6 others like this.
  7. W1YW

    W1YW Ham Member QRZ Page

    No, a balun interfaces a balanced load with an unbalanced load.
     
    Last edited: Feb 25, 2021
    K9EZ, VA7UO, N8TCQ and 7 others like this.
  8. K5SOP

    K5SOP Ham Member QRZ Page

    Balun: A device or method used to match balanced people to unbalanced people.
     
    OE1RSH, HJ2MPD, N8TCQ and 5 others like this.
  9. KA1VT

    KA1VT XML Subscriber QRZ Page

    Called a Choke but also referred to as an Ugly Balun, it works and that is what is important. I made one with terminals for my G5RV and one for the OCF antennas I run. See below. Keep them away from metal, and I supported mine with the loops shown onto a wooden support. I used 2" wide electrical tape - and used 23 feet of coax. ugly choke.JPG
     
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  10. KZ5R

    KZ5R Subscriber QRZ Page

    New Model 1115.jpg 1-1 Compare Air Coax - 1115u.jpg 1115u v Air Wound Coax.jpg

    These three scans are for Carl who requested a scan of an air wound balun. The second graph compares SWR, Transformation and return loss to a toroid wound balun and the bottom graph is choking impedance. The core used in this last graph has since been updated and you can see the choking it now provides in the first scan. Hope this helps.

    Bob, Balun Designs
     
    M1WML, KK4OBI, WA7ARK and 2 others like this.

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