Fold the end of a Dipole Back - What's Happening?

Has anyone told you Cal you’re brilliant? I’m over here with my head spinning! Keep up the great work!

Callum,... you sell SUPERB ANTENNAS because you sell yourself, first!! I make it a habit to watch EVERY VIDEO that you produce, as fast as I can get through each one of them. I have learned so much, even at 82 years of age, with my ticket that I got at age 12!! THIS WAS A GREAT VIDEO to put in my bag of tricks!! Kudos, Callum!!...and I THANK YOU, SIR!!...Ron,.. K6PAM

Thanks Callum I have now realised why my antenna projects had not given me the results I expected on quite a few occasions. I always thought that folding over insulated wire shortened the element. Glad I watched this video.

Of course you are 100% correct. I also discovered this effect about 14 years ago putting up a 40 meter dipole. That is also why I understood your design of the fold-over's of your DXCommander vertical. Excellent video!

Great video!! So this is the reason I got problems to tune my inverted V. Thanks again

Wonderful explanation, Cal - thx!

Just did some of this over the weekend before watching your video. I didn’t come up with any formula but results were similar. Great stuff!

Perfect timing Callum, because I just made a wire dipole for 10/11m and when I tuned 1:1 without loops at end. Then I made loops and found no difference. But you have confirmed for me what was sitting at the back of my mind. 😆 Thank you always for the free Science lesson's. I appreciate you dearly.

You are awesome, Cal! Thank you for these videos, I just subscribed...it would be foolish not to! And thank you for the nudge toward the SWR calculator, i just plopped it right on my desktop. We will be moving out to the country soon and I will be able to flex my antenna wings a bit. Cheers from Maine!

Keep these coming my friend! I watch all your videos and appreciate your hard work. I also share what you taught me with others and credit you as source. :-)

Thank you! I was always curious about that !!

Inspired by your video on making the loaded dipole, I started running a linear loaded EFHW for 80M. Physical length is right at 93ft versus 131ft for a non-loaded EFHW. Easy to make: two stranded insulated wire cut at 93 feet, solder the pair together at one end, at the opposite end connect one strand to the balun and tune by trimming the other strand. Lots of good DX (Europe and South America) from Kentucky. Thanks for all of the practical science. PAX John (ko4hzh)

Well this is a revelation to me. It makes perfect sense though. I'm working on a new 17m rotatable with wire elements. You've given me something to consider while I'm running the tests. Thank you!

I never knew about the foldback at the end of the antenna affects the length. I was taught long ago that it doesn't matter because the antenna would end at the foldback. That must had been for uninsulated wire only! Now it makes sense when I was trying to get a efhw to resonant I had a heck of a time when I had a lot of wire folded back, none of the changes I made made any sense! Thanks for teaching a OM new stuff. Every time I watch your videos I learn something new. I'm definitely saving my pennies for a DX commander!

Very good man… I always wondered about what I would call “folded dipoles” for HF… You’ve given me an experiment idea 💡!

My best guess – is that folding back insulated wire creates capacitive loading similar to a ”capacity hat”. I remember someone tuning an antenna by inserting a ”capacitor” in the middle of an element, only the ”capacitor” consisted of two insulated wires twisted together. He even took those two wires, twisted them together, and measured them with an RLC tester. What I might look into is what effect linear loading has on the radiation resistance, and thus the efficiency of an antenna. 73 de AF6AS in “DM13” land

This is cool Callum,...very often played at Dipol tuning by adding cuting wiring ! Thank you very match for this video !

Great video! when I built my Pseudo commander classic I had issues with the tune. I had taken the fold over and twisted it around itself.... I did not get the correct tune until I made sure the fold over was the correct length and NOT twisted. It is all about the experiment. Thanks for your wisdom!!

Thanks Cal, your timing is impeccable. I just got my Classic setup and have been tuning it using the SWR Calculator and have experienced precisely what you are referring to. Example, I needed to adjust my 40/15M element from 6.98MHz to 7.150MHz which the calculator told me to shorten by 23.76cm. I folded that much back (as well as twisting it) so I didn't cut it and regret it later and it only went to 7.045Mhz which comes out to 38%... pretty darn close to 1/3 which might have been even closer if I hadn't twisted it. Before this video, I searched high and low for the answer as I suspected what you demonstrated. Now I know and can account for it. Thanks and 73s

Shorted vs capacitance because of the small separation of the fold over legs with dielectric in between (air and insulation).