Ham Radio - Improvements to the small magnetic loop build

[@captdaveclearedtoland8876]

That is absolutely amazing. As I mentioned in my previous post, I started building loops when you were living in your old house when I watched your videos. I just have fun building them and now I see this reduction gear is even better. I have a friend of mine who has a 3-D printer so he’s going to make me one thank you for all your hard work and ingenuity. I can’t wait to get one.🎉

[@slk23]

My WSPR station picked you up on 20m on Oct. 23! I love these antenna build/experimentation videos.

[@loughkb]

I've often wondered if somebody who picked me up will have noticed when I did the video. Cool.

[@ohyeawhosurpoppy]

So good to see you bright eyed and bushy tailed put out HAM stuff.

[@johnk8091]

Thanks Kev - you have always maintained in the past that the coupling loop needs to be as close as possible to the main loop, and preferably, oval shaped so that there would be more of the feed loop closer to the main loop. I will try your new method - thanks

[@loughkb]

And on some frequencies with this loop build that was still how I got the best match, with the loop pressed up against the big loop. Making the coupling loop adjustable just showed me that it's not always the best position.

[@johnwest7993]

Very nice job. All that's left is to further increase the Q of the loop, thus increasing the radiation efficiency on Xmit and narrowing bandwidth to reduce noise pickup on RX. It looks like your loop was broadcasting out of a window on the north or northeast side of your RV. I used to use my cellphone in my RV when up in the mountains, and I would place the little dipole antenna in the rig where it would only 'see' out of the front window. I even put grounded aluminum foil on the kitchen window and back window. Then I would point the RV so that I would hit a weak 'local' cell-tower back in my home coverage area instead of a much closer and stronger 'roaming' tower that cost much more to use but to which the phone would automatically flip because of its signal strength. I called it my 'window beam'. I should have built an actual multi-element beam, but I was lazy, and the window-beam worked fine.

[@notionocean]

Well done, Kevin. And it is great to hear the energy and enthusiasm in your voice again. It's a far cry from Kovid Kevin! Welcome back.

[@loughkb]

Oh, I have a long way to go. You're seeing me in the morning where I have a couple of hours of near normalcy. By afternoon I'm on the couch with a headache and no energy. Still getting a bit better month to month.

[@WECB640]

This is a great design on the coupling loop! Congrats Kevin. I believe it's acting as a variometer. I see the entire magnetic loop tuneup procedure somewhat similar to using a grid dip meter. You want very light coupling to find the resonant frequency of the loop first, then increase the coupling to transfer as much power as possible into the loop. The additional coupling will "pull" the resonant frequency of the loop, just as there is in a grid dip meter. Additionally, I would recommend that we hams pay a bit less attention to SWR, and more attention to the field strength of the antenna. That's just the opinion of this OM. 73

[@chuckk5358]

Very nice work! the clutch idea is killer!

[@colincolin30]

Kevin ,I have played with magnetic loops and had reasonable success. What you have discovered is new and now I will get 3d printing soon to make some parts. Thank you.73 Colin VK2JCC

[@loughkb]

Well, rotating the coupling loop isn't new, older texts on maglooops discuss that.

[@Aimsport-video]

Brilliant. Glad to see you back at it. Looks like 6:1 reduction would work even better. Oh and when you are asking for a signal report… say you are full legal, 59ft tower, three element yagi… and when they give you a 59… say “oops” using my QRP 4.7W MagLoop. Too many people sitting on full legal rigs can’t stand it when QRP hits 9. Sad, but true.

[@loughkb]

I'm actually working on developing a stacked two stage planetary gear transmission with a 12 to 1 ratio that takes up less space than this first unit does.

[@jansugalski546]

Glad to see you are back in business. KX4RG

[@robertruth3281]

Really nice work Kevin!

[@johnorrells3797]

Very interesting on the tuning

[@R50_J0]

You’re looking healthy and happy. Good to see that.

[@UDX-340]

That gear unit is sweet , and the loop is great , ive built 2 loops and both were not good ..will keep trying .

[@gamlemann53]

Very nice magnetic loop! The best to you from LB1NH 🙂

[@MountainRaven1960]

Got to hand it to you, you've done a great job!

[@williamgrice4790]

Kevin, you mentioned your clamp for the Coupling Loop. I remember you talked about in a previous video that an Ellipse worked much better than a Circle. Could you make your clamp in an elliptical pattern as well? Not to mention, using a similar herringbone gear to even further "fine tune" it to be slightly out of or back in full plane with the Larger Loop? just a thought. Great job. When I finally get my Capacitor I will be constructing my mag loop based off your builds. KI5IUF 73's

[@loughkb]

The top part of the form flattens out allowing you to press the wire up against the loop to deform it slightly.

[@williamgrice4790]

@@loughkb Thank you for that information. Going to get your gear 3D printed (credit all to you) and a smaller version. So 2 herringbone gear clutch gear boxes. Thanks again.

[@ericwalker3368]

Very nice gear and clutch for your magnet loop.

[@OldinMariner]

another great video, thanks Kevin. I have seen where flatting the drive loop will help the coupling also

[@loughkb]

Yeah I did a video on that a few years ago. That might be where the idea originated.

[@dougtaylor7724]

Kevin, I think you have found a way to generate income. The standoff and gear unit are brilliant.

[@loughkb]

It's not feasible. Far too much time and energy involved in the production of each to make it profitable. 3D printing is good for one offs, but not profitable unless you have a print farm with dozens of printers and a huge electric bill.

[@andrewking3087]

Very nice. QRP is a great way to learn.

[@mikethees6434]

That coupling loop thing is cool if I am ever forced to take down my big antenna (DX Commander) I'm going to have to build a mag loop

[@olivierconet7995]

I like the tunable coupling loop. Great idea. Now I need to find a RV. I want to use my loop antenna inside of it to get the same good performance 🤣

[@martymctry20]

Adapting to other pvc pipe diameters can be easily done with variables in the model if you provide native modeling program's file format.

[@loughkb]

Anybody at that skill level would just remake such a simple model themselves in minutes.

[@garylanders1470]

Awsome job!

[@njjensentube]

Hi Kevin …. That little island 🏝️ you mentioned at Africa’s west coast is the canaries… the island you don’t want to visit, because if you go there you’ll NEVER go back 😂

[@rogerp5816]

Could you add a fine tuning capacitor in parallel to the main tuning capacitor? I'm thinking the fine tuning capacitor would have only two stator places and one rotator plate giving you lots of trave with minimal capacitance change.

[@loughkb]

I have built two loops like that in the past. I had a second smaller geared down cap in parallel with the primary. There's a video on it somewhere back in my catalog.

[@RatchetFWD]

I dig the foray into gearing this bad boy

[@2852GUS]

Great to see you again and super improvement tips!!!!! Remember how many teeth on the gears?

[@MakeDoAndMend1]

I use car brake pipe etc. Vid = "FT8 Digital Mode. Ham Radio. Magnetic Loop Aerial. #ham" Cheers from old George

[@Greatlefty300]

Great job !

[@bctoner]

Well done

[@paulswift700]

I found that using gamma match made the loop usable without having to rematch it when changing frequency and bands. Just the tuning

[@karlhill6652]

Really great job there Kevin! A question, have you ever tried or had anyone show you using a variable capacitor for a mag loop dipped into a container with oil (mineral oil) to be able to increase the voltage it can handle and what the results came out of it? It's easy to get your hands om small capacitors rather than the biggies that costs slot not to mention the vacuum ones. Colud you do any test to these myths? Btw. I am sooooo pleased to see you back in the van and that your health is getting better by the day. Hang in there, you'll pull thru! ❤️

[@loughkb]

Well all you really need to do is look up the dielectric constant of mineral oil compared to the dielectric constant of air. If it's a better insulator then yes it would improve the voltage threshold. I don't have enough power to test it. I'm mostly QRP and can only get up to about 35 Watts with my amp. I just did a search, and mineral oil is a much stronger dielectric than air, a better insulator. So therefore it would definitely raise the voltage tolerance. No need to test it. It's not a myth

[@TerryGilsenan]

That was excellent! thank you.

[@mikethees6434]

Transmission is cool too

[@ouijim]

Changing LOOP antenna "material" (aluminum or copper) to much larger diameter tubing WILL improve efficiency ; ) I switched from wire loop to 1/2" copper tubing and it functioned much better ; ) Planning to try much larger aluminum tubing.

[@loughkb]

Yes, my first magloop was made with copper pipe. However, this is intended to be a portable loop, so coax makes it much easier to transport.

[@ouijim]

@@loughkb Using MFJ-936C loop tuner with 4 ft Loop of 1/2" copper tubing for 10 meter Net Night (portable) On German Hill which is highest point in area about a mile from my lowest point (10 ft above sea level) (home) ; )

[@SX939]

Keven; very interesting. I do believe closing the loop has the effect of improving the Q of the Loop which is the primary antenna. As far as your adjustable coupling, I think there is more to be seen as to improving the match. Moving the coupling loop does effect the Primary antenna however so does the capacitor. My question is weather or not you are only "HIDING" the SWR in return loss. Example being that an antenna measured at its feed point with 1.2 : 1 match ratio can be seen as a 1:1 match ratio measured at the transmitter with a long transmission line. I am not calling you out but am wondering myself since I am intrigued with big high power magnetic loops i have been building large loops using Vacuum capacitors and 12 foot loops of 2.25 inch hard line. Respectfully as always, Dennis KV4WM, A US NAVY NUCLEAR SUBMARINE VETERAN, Broadcast Engineer, and Fellow Amateur Radio Operator 73

[@loughkb]

If you look at earlier textbooks on magnetic loops, they refer to rotating the plane of the coupling loop in order to improve the match. It's similar to how a veriometer works as I understand it.

[@AlexejSvirid]

Quality is frequency dependent. It means your main loop impedance is different on different frequencies for R=ρ*Q. To obtain a good match you should have a set of coupling loops or adjust your coupling loop to current frequency.

[@JAMES-KB7TBT]

Very Cool

[@geraldcampbell6834]

I can get a nearly 1 to 1 match on my Chameleon Ploop magloop antenna by adjusting the Velcro that holds the small loop farther apart so the more of the loops touch and making the main loop more of an egg shape

[@loughkb]

I did a video on 'squashing' the coupling loop awhile back. I also did the same with my chameleon, but couldn't get consistently low on all the bands.

[@travelcanon847]

What i have found out, and also read somewhere is that the coupling loop works better if its oval like an egg, that way there is more skin between the 2x loops, just a thought

[@loughkb]

Yes I did a video on that, "squashing" The coupling loop. I think it's titled magnetic loops one change that makes a big difference. However as I'm discovering now, it might not be the best option for every area of frequency the loop covers.

[@travelcanon847]

@@loughkb Hi and thanks for the pingback, yes there could be many parameters that we need to test more thorough, thanks for coming back, and hope you get the cov id thing in order

[@loubarbaglia8174]

Hi Keven great job on gears and the couch. I HAVE PICTURES OF MY MLA 20 FOOT WITH MOTORESED COUPLING LOOP AND CAPACTOR BUT DON'T KNOW HOW TO SEND them

[@fpaolo63]

hi Kevin, interesting gear ... why not a video on design it with freecad ?

[@loughkb]

This week's 3D video will be looking at the gear workbench in FreeCAD

[@ronleblanc9832]

I had bought one of those cheap loops on ali express...if i make a slightly smaller loop on the same equipment would it raise the frequency range ?

[@loughkb]

Theoretically yes. I hope it's not this loop. kzbin.info/www/bejne/fouUaYmBdrJ4r5I

[@CamilleCullen-ow6qj]

Another amazing video!! Robert K5TPC

[@ICEDoTDK]

god job Kevin

[@protektwar]

once with the vid where you explained what and how you did your magLoop I started to make a box for my magLoop Capacitor... I overthinking it... now is in standby

[@biringen]

maybe a 24:1 gear ratio using a steppermotor controlled by a arduino could be a idea… for remote adjusting the capasitor

[@loughkb]

That's been done several different ways. Ideal for when the loop is in the backyard and your shack is in the house.

[@Don-ev5ov]

The loop is of course one inductor, but with the induced current traveling the same direction in the loop, the mutual inductance across the gap should increase as the gap narrows? So, by narrowing the gap you are increasing the inductance of the loop? I did a search on ”variometer magnetic loop” and the first video KZbin retrieved was one by you from nine years ago. The clutch is brilliant. Edited to add: Ah yes, I remember your bucket variometer build - fascinating.

[@blugoose86]

Question: Did you print these with PLA or PETG? Being new to 3D printing in itself, I was wondering which would be better. Also should I set the Prusa Slicer for .12mm, .10mm, or .08mm?

[@loughkb]

There's really not a lot of torque on the gears or the assembly. So PLA is fine. I printed most of it at 0.2 layers, except the output clutch and the input gear/shaft. Those two are printed at 0.15 layers with 40% infill and three perimeters. To give them more strength. The knob I printed with variable layers set to smooth just to give it a better feel.

[@blugoose86]

@@loughkb Thank you for the quick answer. I'm warming up the printer bed right now. I'm really excited about the new FreeCad too!

[@DIYDSP]

Nice engineering. How did you fab the metal parts? Im still new to HF and researching what antennas to use and hopefully build.

[@loughkb]

I didn't make any metal parts. The form and clamps for the coupling loop are 3D printed, as is the frame the capacitor's mounted on and the gear down assembly. They're all printed in PLA plastic.

[@DIYDSP]

@@loughkb oh! How about the herringbone gear and knob? They look metal? What material are they? Ps i just watched 3 more vids on mag loop. Might be perfect for me as a next step. Ofc i will begin manual tuned :)

[@loughkb]

@@DIYDSP They are printed in PLA. A color called " silk silver " from geetek.

[@Philip-KA4KOE]

Nice!

[@MrStanwyck]

That’s an awesome design for your loop and gear reduction. Where did you get the variable capacitor from? Bill KC2KNA

[@loughkb]

I talked about that back in the design video. It was a sale on ebay. Alliexpress has many sellers with new stock of various types, and there's always a guy at a hamfest with a box of them.

[@MrStanwyck]

@@loughkb thanks Kevin!!! I did find your design video. I can’t believe it’s that hard to find a manufacture of these capacitors. I wonder where Chameleon gets them for their F-loops. Have a good day….

[@wojciechb7896]

Hello, could you give the capacitor parameters or the company name? I would be grateful. Wojtek SP9DLK

[@loughkb]

That was discussed in the design video. It was a purchase off eBay of a single unit. somewhere around 30-170pf as I recall.

[@vladnurk4710]

metric equivalent 3/4 " is 19 mm

[@loughkb]

19.05 mm to be precise.

[@Homer19521]

Herringbones are sexy, but why? Less backlash? Scissor spur gear would work for that (backlash) but maybe harder to execute. Certainly don't need the herringbone for torque or power requirements. Very nice job!! 👍👍👍

[@loughkb]

Zero backlash with herringbone gears. Makes it easier to fine tune when you don't have any play in the system.

[@EricMarshallva]

prettycool!

[@Charles-g5d7k]

👋🏻K. from C.

[@loughkb]

Hi C.

[@ronleblanc9832]

Super interestinh