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Thread: Inverted V Dipole Balun and UnUn

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    Wink Inverted V Dipole Balun and UnUn

    Name:  1-1 to 4-1 Size 2 Fit.jpg
Views: 71
Size:  16.5 KBInverted V 4:1 Balun w/ 1:1 Choke

    For Critique. Output SO-239 to Inverted V Dipole Header also w/ SO-239.
    2.4 x 3.7 ABS Case housing 1:1 and 4:1 UnUn/BalUn. Iron Toroids 1.65 x 0.95" ID; heavies @ 67.5g [2.4oz. (cheap)]. Inverted V Dipole Header would be attached above BalUn Case. Rotate image 180 degrees.
    10AWG solid copper 12-10M Bandwidth.

    Preference for Inverted V comes down to an arrow shot, or thrown rock. over a 40-60' height limb with fishing reel line attached. 550 paracord, one tall tree is all thats needed and no climbing.

    Added: [1] Will use 12AWG magnet wire x 12 windings (2x0.0828x12 = 1.987) inside circumference 2.95". Should be good for 450W RMS. Image shows spacing off. Actual will be closer to 1/6" inside (0.08) and 1/4" outside spacing. [2] Graph indicating 10 windings = SWR 1.1 and 14 is better, for 10/11M. 12 is happy medium.

    Dave Castler, KE0OG see UToob; says heat build up on toroid (assuming common mixtures) can cause them to shatter and/or become over magnetized. Got me to think longer on these iron toroids, while they may become magnetized quicker and possibly remain so, I can't imagine them shattering. Must say, Amazon seller Brand: Taigoehua is obfuscating answers to my inquiries as to permeability or material mix. A chance purchase at best.

    You gotta hate this: Product inquiry 1. Q: What is permeability. A: by J. Awph (received definition for permeability); and inquiry disappeared. Inquiry 2. Q: Mix 77 permeability 2000, Mix 31 permeability 1500, Mix 43 permeability 850, what is permeability of these Toroids. A: by BJ Lewinsky, "Yes" ; and again inquiry disappeared.
    Last edited by Alabama Buckeye; 04-13-2022 at 02:40 AM. Reason: [2] Happy Medium; chance purchase
    All answers are opinions and may, or may not be technically correct.

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    Asking out of curiosity...... why the 4:1 balun?

    My understanding is that a normal horizontal dipole is 72-75 ohms impedance....
    and when you slope the arms down... that actually lowers the impedance much closer to 50 ohms...
    meaning it will match like that. I would certainly still put the 1:1 in there.....
    But I find myself itching that the 4 to 1 would drop that 50 ohms to about 12.5 ohms.

    I usually only see 4 to 1 baluns on loops and folded dipoles as those have 200 to 300 ohms impedance.... so they NEED to be transformed downward towards 50.

  3. The Following User Says Thank You to Bobcat For This Useful Post:

    Alabama Buckeye (04-15-2022)

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    Thanks Bobcat for reply. GD server is again p1$$ing me off. Wrote a response and submitted and it sent it to byte hell.
    Sure won't be donating again til this crap is fixed.
    All answers are opinions and may, or may not be technically correct.

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    By golly it sez it right there: Dipoles have a feed point of about 75Ω in free space, and can be fed with 50Ω to 75Ω coax with or without a 1:1 balun. Inverted Vee's present closer to 50Ω due to the effect of the ground being close to the tip of each leg. Feed your inverted vee with 50Ω coaxial cable, with or without a 1:1 balun.
    Inverted Vee Antenna – M0UKD – Amateur Radio Blog https://m0ukd.com

    My initial Inverted Vee had 0 activity while Imax 2000 was awash with activity during past Solar Max. Used Tuner to no avail.

    Now have a couple 1:1 UnUn Chokes with uses in mind. Was going to try different design 4:1 which incorporates choke windings using the 2x 1:1s.

    Again thanks Bobcat.
    Last edited by Alabama Buckeye; 04-15-2022 at 01:05 AM. Reason: speeling
    All answers are opinions and may, or may not be technically correct.

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    Any time! I hope you get that thing "up in the wind" and pull down some signals!

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    Was going to go with this design to build 4:1 in lieu of my previous inspired design, Simpler. Made them up, not with 12AWG solid copper; found to be too hard to wind. After Bobcat's advice I now have two Choke UnUns for in shack for attachment to TX/Rceivers. 100W maximum.
    4:1 Current Balun | M0PZTm0pzt.com



    All answers are opinions and may, or may not be technically correct.

  8. #7
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    Thank YOU for that reference article. I collect info like that. Converted it to a PDF file using the Print Friendly site.... so I can save it easy!

    Thanks again.
    Bob

    Quote Originally Posted by Alabama Buckeye View Post
    Was going to go with this design to build 4:1 in lieu of my previous inspired design, Simpler. Made them up, not with 12AWG solid copper; found to be too hard to wind. After Bobcat's advice I now have two Choke UnUns for in shack for attachment to TX/Rceivers. 100W maximum.
    4:1 Current Balun | M0PZTm0pzt.com




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    Why for sake of balance, "In order for each end of the cable to be opposite to each other, there is a crossover point – there is no performance change when doing this and you’ll see many examples of Baluns that have this trait", he didn't wind 5 X 5 in lieu of 4 x 6.
    I used 18AWG, good for 100W, and squeezed 10 winding around my new found iron toroids. Inside circumference 2.95" a tiny bit larger than 140-xx @ 2.83". Used 3 stranded wire for rotor; came in handy with 3 colors, red/white/black.
    Last edited by Alabama Buckeye; 04-15-2022 at 03:37 PM. Reason: speeling
    All answers are opinions and may, or may not be technically correct.

  10. #9
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    I am thinking of trying a "folded dipole" using ladder line to build it.

    For one, it would be horizontal...a little better for DX,
    They are also a little more resistant to "noise" and I am kind of plagued with noise in the suburban area I live in.
    Since it is a wire antenna it will be cheap enough....
    And to keep it cheap it uses a "coax balun" wired in that does the same thing as a 4:1 balun.
    Folded dipoles are inherently about 300 ohms so a 4:1 transformation will bring it down to 75 ohm... which is the same load that a standard dipole presents so it should work fine.

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