HAM RADIO: Building a magnetic loop antenna Part 2.1 Capacitor Track

[@974twinmill2]

What a slick idea. Easy and allows a repeatable result every time. Great work Mike

[@mike-M0MSN]

Thanks 👍

[@bobyk87]

hams really know the art of repurposing materials, ingenious indeed.

[@krisraps]

This Is The Coolest Antenna Concept I Have EVER Seen !

[@mike-M0MSN]

Thanks Kris

[@Joe-KN4IFI]

Brilliant work Mike. Looking good. 73 Joe

[@g0fvt]

Very ingenious, well done. Watching the video I wondered about using some of the plastic curtain tracks, they make all sorts of different cross sections. A very ingenious project, thank you for sharing.

[@mike-M0MSN]

Thank you! Cheers!

[@PaulGrahamM0PGX]

Looks good :) I'm kind of following you, except I'm using a lead screw from a 3D printer and a stepper motor. It's nice and straight. I also printed spacer cylinders to go between the thinner copper pipe and the plastic conduit and superglued the thinner copper pipe, spacers and conduit together so the conduit and copper pipe slide in and out of the thicker pipe. I've had a 1.9m copper pipe loop sitting in the outhouse that has been waiting for a capacitor for years, you've finally pushed me to do something with it! :D

[@mike-M0MSN]

Fantastic, great idea with the 3D printer, must get myself one.. :)

[@andrewandrosow4797]

Hello! You spent lots of time to make this capacitor! What is the capacitance of this capacitor ? I think - 30-60picoFarads. Right?

[@mike-M0MSN]

Yep about right

[@icorezx14r]

Did I miss something. I haven't seen a signal report for this build. Was it a failure? Did it get multiple bands with good performance? Did it only work on one band? A lot of work for no on air performance testing...........

[@mike-M0MSN]

Yes ok, there is a lot of uploads to look at, but to help, it works well.

[@icorezx14r]

@@mike-M0MSN that's what I wanted to hear, thanks for the reply!

[@ianxfs]

Brilliant! How good is that?! 👍🏻 (ps. Did you remember to empty the tumble-drier while you were in there for brownie-points 😁)

[@mike-M0MSN]

LOL, yes yes...

[@on2mvh937]

What is the voltage the pvc pipe can isolate in kv ..?

[@mike-M0MSN]

a round 4-5K maybe more...

[@abdula4699]

Excellent job

[@ben2e0omr]

Great bogery, Heath Robinson. Brilliant British engineering.

[@mike-M0MSN]

Thanks

[@markg6jvy135]

Great project Mike and nice to see you improving on it 👍

[@mike-M0MSN]

Thanks 👍

[@BoB4jjjjs]

So you used your loaf, or rather your window guide. Well, it works, what more would you want?

[@DonDegidio]

Hi Mike, Excellent solution. Now time for more contacts. :-) Stay safe. 73 WJ3U

[@mike-M0MSN]

That's the plan!

[@Testalan1212]

Just a thought, is that track not going to change the tune being so close to the trombone.?

[@mike-M0MSN]

Alan Briscoe seems to be ok..

[@eventail2001]

@@mike-M0MSN Convention suggests having a chunk of metal inside the loop should be avoided. How to measure/prove this I do not know. About to start on my third loop one metre diameter of 15mm tube in a single piece round loop.

[@mike-M0MSN]

Nigel Evans yep you maybe right, but experimenting is fun...

[@glenmartin2437]

Thank you.

[@mike-M0MSN]

Welcome!

[@PaulRyder]

Inspired idea Mike!

[@blugoose86]

Hi Mike, great inspiring video. I was looking for part 3 the on air demonstration. I was also wondering if you added limit switches on the slide to stop the motor from trying to wind past the ends. de KA9TII

[@mike-M0MSN]

Need to do a follow up to this video

[@MidlifeRenaissanceMan]

Hi Mike I made my magnetic loop from 1” x 1/16” aluminium flat bar / strap. The loop is 8m circumference and only needs around 70pF to tune 7MHz I’m using a couple of stacked T240-43 as a transformer couple. It requires more driver side turns on 7MHz than on 14MHz. I haven’t tried it on 10MHz, I imagine it would be somewhere in between I built a small motorised piston capacitor out of 20mm electrical conduit covered in copper foil into a 25mm conduit tube with aluminium flashing wrapped around it side by side on the same piece of conduit The capacitor was good to around 20W CW on 7MHz. Anything over 40W and I was getting flash over and arcing through the plastic conduit I was using as a dielectric. After using electrical tape for extra insulation, I can get 60W or so, but still can’t get a dollar into it without arcing Out of curiosity, how much power are you running into the loop ?? I must admit, the aluminium strap is so much lighter than the copper tube. I found someone who does extruded fibreglass reinforced structural drawn plastic bars which is what I am looking at using to frame the antenna. Keep the weight down for a permanent mount on my rooftop

[@mike-M0MSN]

Thanks for the info :)

[@MidlifeRenaissanceMan]

@@mike-M0MSN cheers How much power are you running into your loop ???

[@pmueller071]

Great, why not use an electrical linear Actuator, or an Hydraulic one?

[@vk2ir1]

Great job Mike! I like that window channel de Tommy vk2ir

[@mike-M0MSN]

Thanks!

[@johng7rwf419]

Very good, another source for a track would be drawer runners. Numerous domestic types are available.

[@mike-M0MSN]

great tip :)

[@AliReza-zx8km]

Nice........

[@mike-M0MSN]

Thanks

[@hobbyrob313]

563/5000 Sorry but the motor shaft and threads are out of alignment! At the top I would the house which normally should be a bearing house (not ugly intended!) I would remove that House at the top(bearing house ) Leave the thread to swing back and forth a bit, doesn't matter that much. I have the same with my Prusa i3 3D Printer and it works perfectly! At the top the 2 threads swing back and forth (the guides keep it stable) (if you lock the screw thread it will only get stiffer) Unless everything is straight and in line of course! Make sure that the bearing house (which is close to the engine) is of good quality! Friendly greetings from The Netherlands! Rob

[@mike-M0MSN]

HobbyRob Thank you for your post I need to have a look. 🤗😀

[@hobbyrob313]

@@mike-M0MSN By the way, didn't you have a 3D printer yet Mike? is really worth it! it may be difficult at first but with with a bit of research and experimentation and a little luck ... I don't think building it yourself is that profitable anymore, a KIT is probably the best thing to buy! Kind regards from the Rotterdam area again! Rob

[@krisraps]

Sad Thing These Days Is That Everything You Buy Is A Bit Faulty And For Us, People Like Us , We Need Everything Perfect For SOme Projects And That Lil Bit Of Fault Makes The Project Go To PooPoo ! :( I Had These Problems So Many Times With So Many Projects, But Gladly Wood Is The Thing I Get The BEST One On Planet :) Baltic Birch Plywood, Its So Good For Any Projects And I Get It For Dirt Cheap here

[@kevinkc3onohelijeepworld953]

Nice fix good thinking and look economical vs a track slider set up with bearings 😉 KC3ONO

[@mike-M0MSN]

Thanks 👍

[@josebrivera1716]

I find your mag loop too complicated. This video deals with mostly with a motorized tuning. It’s a lot simpler doing it by hand.

[@mike-M0MSN]

so true.. :)

[@johnwest7993]

That's correct, unless you are indoors in your shack and the loop is outdoors up on a post. If that's the case, you'll also want both a remote loop tuner and a rotor, since the ability to rotate a small loop for directivity is a fundamental reason to make one.