Video

This is a clever design that inexpensively overcomes several of the challenges in constructing an efficient mag loop antenna: low resistance loops and expensive high voltage capacitors. I'm off to the hardware store.

Hi Dennis, is Jacob here XE2YWI, that magnetic loop, looks pretty nice nice and cheap, I wonder for the measure. More exactly on those parts, so I could be able to get me one of those, if you would and be so kind. Thank you 73s

In a few weeks.... news about my copy of this project.

Hey Dennis I was wondering if it was possible to set this up as a ring antenna possibly 2 or 3 rings in a horizontal alignment possibly using stainless horse fencing tape to wrap. To build a omni directional. Rooftop antenna for my schoolbus or my jeep? KJ5DQA

Brilliant idea!

Very interesting design! I’ve been thinking of building a magnetic loop antenna, but had put it off due to finding a suitable capacitor. 73, Tom WA1LBK

Thanks for the video… this is the epitome of ham radio

GREAT VIDEO. Thanks so much. I love it just like I loved the book, _Three Hundred Zeros_!

Loved this Video and Three Hundred Zeros. I have read it and re-read it many times. Permanent part of my library. Thanks Dennis

I like the ideas you used, is it possible that the trombone slide capacitor could be 90 deg. to the loop and still perform well?

That loop is a very interesting design as spiral wrapping the conductive tape around the plastic pipe without the edges of the tape touching then, that meant that a coil was wound around the plastic tubing. This resulted in a magnetic loop in the lane of the plastic loop as if it was a long solenoid and the radiating component of the " solenoid current was that current parallel with the plastic loop. The edges due theor sharpness of the conductive tape was breaking down in voltage stress mode, and would limit the power that " wound loop" could take. Nice idea but that " wound loop is certainly not a simple loop to analyse in depth . Congratulations,

Parlez en français si vous êtes francais

How much would increasing the copper pipes to 1" copper help???

Have you tried a square loop of PVC or pex tubing

Loops are not antennas. Loops are INDUCTORS and do not radiate as antennas, they might couple to some other object. Inductors do not radiate, they conserve energy

For some reason, looking at you explaining, had me expecting to see you float in weightlessness like on these ISS videos 😀😝 Must be the lightning and all the machinery! Cheers

Hard copy?

Dennis, could you thread a 12ga wire thru the center of the pen in the primary loop and bring it outside through a small hole and wrap the 1" shield"? 73 KF0IDJ

Brilliant!

i used to build and sell loops. if you look for pex al pex water pipe it has the foil layer built inside. there are several diameters that fit inside each other. my best seller was 2 turns of pexal with a smaller diameter pushed in to join the loop and form the capacitor. tuning was done with nylon threaded rod to spread the 2 turns slightly. one of these sitting on my workbench in bulgaria got me into new york on 1w

Thanks for the demo brother. I’m ordering one!

As the Brits would say, this is brilliant! Thank you. I gave away my vacuum-variable cap a few years ago because I had no idea how to use it in anything, and I do have some air-variable caps, but I really like this antenna for its electrical conductivity. Do you know its Q? Its bandwidth compared to other loops? Perhaps a sweep with a NanoVNA. I need the bandwidth to be very narrow to deal with the noise at my locale and because I'm running QRP. I ask because the trombone cap has that plastic pipe as a dielectric between the plates, so it will have a somewhat lower Q than an air variable cap.

Experimenting is priceless fun. Great

VERY interesting antenna!

Learned so much thank you

Great idea for an inexpensive but Very Effective Var. Tuning Cap. Specially with the Aluminum Tape and pvc tubing , TYVM for sharing a Great idea 73s

Brilliant. This oughtta win a design contest. Thank you! I want to give this a try. 73 DE NØIP

foil band dont touching copper tube right? TA1APD 73!

Suggestion Instead of the thrombone variable cap

Добрый день! Скажите ,на 27 мгц какой нужен диаметр рамки?

any videos of your out door version ?

The video mentions that the copper leg spacing is 6" but the blog loop diagram shows a spacing of 4-5". Which to use?

good enough

Here is a link to THE COPPER TUBE HANDBOOK pdf document. Bending is described on page 30. www.copper.org/publications/pub_list/pdf/copper_tube_handbook.pdf

Thank you for spending so much time sharing your design!

This works excellent, I built one for cb. My attempt at the trombone wasn't successful (it my first attempt at building any capacitor and I didn't have any understanding of the feel for it ) so I built a simple variable variable plate. It's just two steel plates from the electrical aisle (junction box covers I believe) attached in their corners by a plastic bolt and spaced with plastic nuts and washers. The tape-loop ends are wrapped and soldered around two short bits of copper that are bolted to either plate and a long piece of plastic zip tied to the movable plate and to the mast at the other side allows adjusting with a firm hold. Whether or not it would handle 100w without better connections, I don't know but it works great for 4w. My outer loop is just shy of a 1/4 wave and it doesn't seem to require very much capacitance. Were it smaller or like for multibanding it would need a more so I think my trombone was just too big and I do intend to try again at some point. Anyways, thank you for the video! 👍

Since you are using coax for your capacitor, I would suggest putting a SO-239 at the antenna end and cutting additional lengths to get you on 30 and 20 meters by just switching your cable capacitor. I appreciate you showing a way to make a loop antenna for 100 watts for little cost.

Thanks loved the trailer. I am sure I am going to love this book. Just like Three Hundred Zeros Let me know when I can pre-order a hard copy. TIA !

アルミテープとは奇想天外で面白い。そして、僕にも作れそうです。

Cool

At half of the video I see the best idea of making a loop antenna, very clever.!

This looks a great project even though Im very new to the hobby I would like to try it...but I dont have the analyser to 'tune' the different bands as you did. Is there another way to do that?

Thanks for the neat video and ideas, now i am going to try your tape idea for a vertical base antenna. I have lots of large pvc pipe that will stand up by its self. 73s, N5UEB

good one. hi folks for qrp project see vu3inj.blogspot.com for tx rx trx cw osc dsb etc

Can't wait to try this antenna. Excellent Video.

This has got me looking at the trampoline in the the back yard...hmmmm.

Very nice, I homebrew one with a trombonne for 27 MHz. Nice idea. 7351.

I am collecting parts right now to make one of these. I was wondering if the diameter of the copper tube will change other dimensions. I was able to locate 5/8 ' rather than your recommended 3/4' tubing.

Thanks for this, gave me some ideas to overcome some problems I'm having building my own.

ABSOLUTELY Fantastic. Ham radio LIVES