HAM RADIO: Building a Variable Capacitor, DIY Capacitor, Magnetic Loop

[@wayneparris3439]

Nice job for freehand. I spent a lifetime in Aerospace tooling though I am retired now. When you have a lot of identical parts to make, if you can join the individual parts into a larger block you accuracy and speed go way up. If you want to make another tuning condenser after you cut your plates but before trimming to final shape or drilling any holes, you can use double sided tape (very thin) to join all your parts into a block. Now final sanding to shape will go much quicker and the parts will be all the same. When drilling your holes, all the holes will also be the same. If you have even a small hand drill press, that will keep your drill square to your work and a belt sander or disc sander will make final shaping a snap. With better accuracy you can then reduce the gap between the stator and rotor too. Again, very nice job for free hand work!

[@mike-M0MSN]

Great tip many thanks 😊

[@orangmakan]

He needs that big of a gap because there might be up to 5000Volts between them when used for trimming a loop antenna.

[@philandmia]

Thank you for the inspiration. I have now built 2 for my antenna tuner. Not as hard as I had imagined.😁

[@MrPanetela]

hopefully i an keep this story short. way back in the day, my Dad called a repair man to look at his TV and radio. The repair man first looked at the radio. I as a baby boy thought wow! there's a city in there! The gang capacitor was like a gothic cathedral. Then the repair man giggled and say to my Dad, here's the problem, and proceeded to pull a tiny deceased mouse that had nibbled it's way into the radio for its new home. And of course shorted out the tube while scurrying around in there. Thanks, your presentation evoked a lot of great memories. Wish you the very best, you and your family. This generation will never realize how wonderfully great those days were before everything changed.

[@mike-M0MSN]

Beautiful story, thank you for sharing. best wishes Mike-M0MSN

[@paulperano9236]

Love the idea and great execution too Mike. You could design the plates on a PCB system and get them made through the like of PCBWay, 10m boards for a few pound, then use std brass washers to space them. With double sided PCBs and plated holes it could be very interesting.

[@jbgreer]

I feel certain you've explained how effective the scroll saw is at cutting sandwiches. Very effective. Great work, Mike.

[@mike-M0MSN]

Thanks 👍 almost as good at cutting fingers...

[@jeffreydove2036]

Hi, nice capacitor you made. Though you need to round all the corners or you will leak out at high voltage. I have built some of them also, and yes it is a lot of time. But you have something you built yourself and can now build even better. Great job there. Jeff

[@mike-M0MSN]

Thanks for the tips!

[@joewoodchuck3824]

Nicely done! There's a design I have in mind that's much easier to make. I'll just cut out squares. Drill a hole in one corner for shafts so the square is used as a diamond shape, and nip off the opposite corner to clear the next shaft. I know it's a little unconventional and won't look as cool as semi circles but I'll save a lot of time. Accumulating hardware as I go along.

[@stevenlstout]

It is important to deburr the edges to reduce arcover. I used to make similar parts on a CNC Punch machine. I would check with local sheet metal shops for a bid. They can make complete parts that are drilled and deburred very quickly.

[@mike-M0MSN]

De-bur very important.. and yes next time CNC it maybe££

[@lc79tourer26]

Ahh, I see you beat me to sharp edges bit already, sorry to have made the point again. Something to be said for reading comments first before shooting my mouth off.

[@DavidALovingMPF102]

Nice. the variable caps I use for my homebuilt A.M. radios have gone from $15 to $36. 10 pf to 360 pf. I too am looking into making my own. Thanks!

[@andrewskater8813]

Impressive dedication! I bought an old radio to get the tuning capacitor and germanium diodes and after destroying some of the polystyrene capacitors realised it did not have germanium diodes and was using tube diodes as detectors..............so months later I am slowly getting the radio to work as a restoration project

[@maurasmith-mitsky762]

Excellent video. Lots of work involved. May your new variable capacitor serve you well.

[@mike-M0MSN]

Many thanks!

[@BoB4jjjjs]

You should be proud of that one Mike! Excellent, I would not have thought to try it. I threw a box of these out when I got married, never thought I would ever have a use for them :-(( the daft things one does when moving house in a hurry!

[@mike-M0MSN]

Yes I think I did the same, we live and learn.. :)

[@americaswayout4489]

I think the word you Brits use to describe something fantastic is BRILLANT, so we can go with that. Years ago Crushcraft sold a vertical called an R3 it had some traps for 10,15,20 but also used a capacitor like you just built with a motor and outside box plus it had a control box for inside. I acquired the control box, have a 24-28 volt motor and should have other parts to try to make something work. I also have the driven element from an av4 beam that is about the same as the r3. You make everything seem so easy, but every time I try a project, some hard to find or use tool gets in the way. Trying to build some spreaders for a version of DX Commander the key whole size was not available. You really have a lot of talents !! If you get bored or would like a challenge, I would send you the control box and other parts if you would like to tackle building the outside box, etc to remote tune the antenna. The control box has the voltages etc? Also, the same inside control might be stable with other capacitor tuned antenna like those loops you have built recently?

[@mike-M0MSN]

Maybe one day, but for now I have too much to do... thank you for your nice comments

[@hyperionsixzeroeight5064]

I seem to remember kits being available to construct variable caps. Hamfest flea markets another good source. Surplus military gear (old stuff) another source for us scroungers.

[@stephennelson-smith3312]

Super job - it came out really well! I must say I did chuckle when you baulked at the price of a VC on ebay, and then spent twice as much on just the saw, let alone the parts, but inspiring all the same.

[@problemwithauthority]

I remember the sound of using a scroll saw on metal...makes a heck of a racket.

[@mike-M0MSN]

yep, next time, ear plugs.

[@quebirt]

Very cool. I assumed special materials and exact spacing would be required. I may actually give this a go. I have a very nice variable capacitor that came out of an old ham radio but it's lost in my "collection."

[@thehulkster2707]

Very helpful and an inspiration because the price of variable air caps are through the roof..ty

[@mike-M0MSN]

Glad it was helpful!

[@hydromakers]

absolutely the finest capacitor that i have ever seen.

[@AGeekNamedRoss]

Next time, for that semi-circle notch on the stator plates, try this: Drill the holes first, then cut them out. That small diameter semi-circle is hard to get right with a scroll saw. Also, this project would warrant the purchase of a small drill-press.

[@michelemarchitiello1868]

Complimenti. È bellissimo questo condensarore variabile, costruito con le tue mani.

[@markjhonthan9123]

WoooooW Good job I like . I was want to make one like this but I want made A small variable capasiter

[@Joe-KN4IFI]

Great work Mike. Doing plate after plate can get a wee bit tedious. 73 Joe

[@mike-M0MSN]

yep two days of work one cap... :(

[@chuckmaddison2924]

Impressive, I tried a couple of years back, and it was a glorious failure . After seeing this might have another attempt.

[@omsingharjit]

you can make it's rang more better and flexible by connecting each stationery plate with jumpers connectors or 7 step rotary switch found in Stepped fan regulators and sure you have to seperate all plate electrically .

[@pierre5325]

Mike, most excellent job Mate!

[@SuburbanDXing]

All I can think of here is that if I tried half of the stuff you do, they'd call me "Lefty" (with the local hospital getting plenty of my gear money). Fun to watch your craft, Mike...good stuff. 73! de WX0V

[@mike-M0MSN]

Thank goodness for the NHS

[@SuburbanDXing]

@@mike-M0MSN Indeed...hopefully I will not be in use of their services...keep up the great work here...73!

[@michealbell5042]

Keep up good work I would love to see this with a mag loop🤔👍😀

[@mike-M0MSN]

Maybe???

[@southernexposure123]

Real nice job on the cap. A few years before I bought a commercially made antenna tuner I red necked a tuner together from junk box parts. My coil was the spring which was still in a 5 subject school notebook and the variable cap was from a defunct 9 volt transistor radio. I switched the number of turns on the coil using Rat Shack test jumper wires. You remember those. They had spring loaded alligator clips on each end. Oh, and the 5 subject notebook served as my log book. lol I used it with a 200 watt Swan 400 tube rig and it never arced. My key was a Rat Sheck roller switch - hand held. ((-: Long live CW.

[@mike-M0MSN]

Oh I remember them, great times. Cheers

[@MiscDotGeek]

FB OM! I built one this week too, but I used PCB's and switches. It actually went to about 400pf, but I don't think it would handle the higher voltages that yours would. My channel has it if anybody wants to see. But I like yours a lot- very properly built and as good as any much more expensive one, if not better :)

[@mike-M0MSN]

many thanks I have a visit. :)

[@ahmedisml]

Wonderful job

[@TEGEscalator]

73 Mike, great achievement, but you have to be patient. I was just talking about it this morning with my friend but it will be a 500pf. ps: do not forget to remove the blue plastic which protects the aluminum.

[@mike-M0MSN]

Blue plastic, oh yes

[@ConsertandoTudo]

To people looking for a way to make it, and does not have access to all tools, that could be made using raw printed circuit board and a rotatory (?) sand papper. Prefer fenolite (?) pcb over fiber glass. Great job.

[@johnnydunphy6396]

Top class ..well done .. SIR

[@mike-M0MSN]

Many thanks

[@Stelios.Posantzis]

You could have stacked the plates together and secured them in a vice, with some support blocks judiciously placed, before filing them. That way you could get uniformity. Achieving uniformity with the spacers is more critical to making a precision part and also harder to achieve but still doable. It would be best to cut them using an alignment jig though in order to minimize the filing work needed afterwards in order to get them all to be square cut and of the same length.

[@mike-M0MSN]

Yes, a vice is the next purchase.

[@g0fvt]

An interesting project, well done, I may make similar but using double sided PCB for the plates with brass hardware. Watching the test I got the impression your minimum capacitance would be lower if the lower pates were a simple rectangle below the spindle. Not being critical but would make construction a little easier. I do see some companies offer water jet cutting..... might be worth looking into?

[@mike-M0MSN]

Great idea

[@PE3FS]

nice prototype and a lot of work . I hope you don't forget to peel of the plastic from the alu. The value is a bit different then. But I am sure you know. looking forward to the next video

[@mike-M0MSN]

Thanks, will do!

[@MrMrsteve01]

Those flux capacitors are crazy. Total banana bibulation and scheming. Been thinking about doing it in a full stasis pizza loadout.

[@krishnaananda3617]

Hello! Amazing! Thank you.

[@husabyrr6496]

Très bonne vidéo. Je me lance pour en faire une.thank you.

[@whamni]

Brilliant Mike, soon as I saw you using the file I knew lol

[@mike-M0MSN]

;)

[@lc79tourer26]

Very nicely done, My only thought would be to try and get rid of any sharp edges that might help avoid arching, other than that, a good effort.

[@harryszwergstatt2879]

Really great job!👍

[@philippejoigny5928]

Congratulations Mike for this wonderful achievement! 73, Philippe (F1PBT)

[@mike-M0MSN]

Merci beaucoup pour vos commentaires

[@sheilamoore6255]

Yes, all you need is a 300 dollar table jigsaw, some high-dollar aluminum plate material, etc., etc., to make your very own variable capacitor!!! Great!

[@mike-M0MSN]

😂😂😂💋

[@thefallenone7988]

Good job because they get an arm and a leg for them these days if you can find them. Although some can be had at a decent price if you look hard enough. 😎👍

[@mike-M0MSN]

To true 😀

[@warrenkeillor9034]

That is inspiring! I too have always wished to get a big air gap capacitor. That is a nice simple design. I wonder how large of range one can possibly get with this concept, going big?

[@Timtron432]

Hi Warren, A friend of mine that has a cnc water jet cut all my parts for a very very very big air variable cap lol 900 pf minimum to 1.8 uf max that i put inside a plastic sealed clear box. I use it to tune and find the peak's when i tune the coils of ( Not A BiTT or A BiTT ) The variable 1.5 uf cap is used with other ac caps to get in range and find the peak output of the BiTT or Not A BiTT.. Cheers!!!

[@jmd62800]

Fantastique job !! You are in crédible , you transform idéal in real !!! ( not,so easy) congrats 👍👍👍

[@DedyBlackLaBeneamata]

incredible idea

[@mike-M0MSN]

Thank you! Cheers!

[@jdmccorful]

Very intriguing idea. You need some practice with your saws, learning the best blade with the right speed. Scroll sawing is an art. I've wonder about doing this and you have given me a push to investigate. Thanks.

[@mike-M0MSN]

Thanks 👍

[@sagorreza114]

Wonderful built! Impressive.

[@mike-M0MSN]

Thank you! Cheers!

[@TechTed1]

Great job there

[@Dr._Spamy]

One trick to drill holes from even distance is to drill a clamped stack of roughly cut sheet metal peaces all at once. The final shaping could be done after the drilling then.

[@antonioroccuzzo4214]

Nice job 👍👍👍👍👍

[@mike-M0MSN]

Thanks 👍

[@johnpeterson7264]

Marvelous !

[@johng.3740]

Good job building the capacitor! I'm wondering if you could cut the individual capacitor plates from plastic or wood, then cover them with a layer or layers of aluminum foil.

[@mike-M0MSN]

Yes you can!

[@jean-marcparatte5564]

Fine work.

[@mike-M0MSN]

Many thanks!

[@francisauspert513]

Thanks Mike (Belgium)

[@michealbell5042]

You have inspired me to build one it's over halfway done. It's very time consuming I don't know if I will do it again😅

[@mike-M0MSN]

Yep, two days of cutting and filing and drilling and printing and.....

[@chazrw2chz290]

Nice build. 👍👍 Although I'd likely be lazy and outsource the cutting to a friend that has a plasma cutter. 😉

[@mike-M0MSN]

A friend yes, but a company!!! way to expensive..

[@chazrw2chz290]

@@mike-M0MSN Without a doubt. Really liked your video, gives me all sorts of ideas.

[@kellypaws]

It’s a talented piece of work, and VCs are expensive. But, and it’s a big but, looking at the tools you have to own, and the time it takes, not to mention the skill, obviously the skill, I was rather thinking there’s a reason they’re dear.

[@binal5542]

Nice

[@josephleister9198]

Excellent work...thank you for sharing.

[@mike-M0MSN]

Thank you! Cheers!

[@kariolavi]

Looks great Mike! I´ve used a cheap nibbler attachment on my drill. The thickness of the aluminium plate was 1,5 mm and it works fine. Some filing is still needed of course. 73 de Kari OH2BCY

[@mike-M0MSN]

Great idea.

[@jeanlouisberthault7603]

Very nice job, have a nice day, JB from FRANCE

[@mike-M0MSN]

Thanks, you too!

[@monolito8556]

beautiful !

[@AdamosDad]

This is real HAM Radio!

[@mike-M0MSN]

Many Thanks 🤩

[@andyquattro]

Fantastic work Mike ! I've subscribed so I don't miss the roller coaster inductor video ;-) 73 Andrew G1PPZ

[@mike-M0MSN]

Welcome aboard! and that's a great Idea too.

[@Stelios.Posantzis]

Good call. Ebay prices on these things are astronomical. I guess most of those items have long been scrapped or are simply rotting away in sheds or labs.

[@mike-M0MSN]

yep!

[@crazycrab8578]

need this for me crystal radio , nicely done

[@waynedavies3185]

Excellent video.... well made.

[@Tump2010]

need to get the foot to sit on the work to keep it from jittering. :-) You need to add a disc or belt sander to your tool list to help with the shapes and edges.

[@mike-M0MSN]

Good call!

[@Aimsport-video]

Bravo!

[@KenPaisley]

Nice job. A belt sander and a drill press might make that a lot easier. Why did you leave the plastic film on the plates? Wondering if it changes the capacitance. I would think it does.

[@flapjack9495]

I was wondering that, too. There's no good reason to leave that film on there. It shouldn't change the capacitance too much but it might increase the dieletric losses.

[@ianxfs]

I’m very pleased too Mike 👍🏻

[@mike-M0MSN]

Cheers Ian

[@ben2e0omr]

Excellent build Mike. I shall put my order in now please.

[@mike-M0MSN]

ha ha,, :)

[@M7XCB]

Excellent work love making my own things bet your miss not happy about chest freezer lol

[@mike-M0MSN]

You got that right!, but you should see the kitchen......

[@M7XCB]

@@mike-M0MSN haha bad as me I had yaesu 767 Gtl DX on the kitchen table apart for over 1 week yer it took me to fix it my wife was very supportive at least she knows where I am lol

[@jeremycole3008]

very nice build. i like it

[@boxingday11]

Thanks Mike 👍🇬🇧

[@andylinton2798]

Nice work! But I wouldn't have had the patience to cut out that ally, I'd have got some metalwork place to CNC cut it!

[@mike-M0MSN]

Next time!

[@MichaelEdelman1954]

Saw this and immediately subscribed. Very nice.

[@mike-M0MSN]

Awesome, thank you!

[@attilarivera]

👏👏👏👏👏👏 Thank You!!! ✌😊👍 💚💛💙 🇧🇷🇧🇷🇧🇷

[@iestynwyn4311]

good job mike. you should have been in the A team tidy

[@mike-M0MSN]

Merdoc, or Face-man

[@GeorgeWMays]

That is very cool. Thank you for a truly interesting video. It is much appreciated.

[@mike-M0MSN]

Glad you enjoyed it!

[@JoseSilveira-newhandleforYT]

Looks good! I wonder, with all the work and expense, if it would not have been more effective to have them cut (water jet or laser) professionally - you obviously have the means to draw the CAD files required. That would also benefit from tighter specifications, allowing for smaller plate gap and smaller size for the same range of capacity (unless you are going for an high voltage application).

[@mike-M0MSN]

Yes Jose, Laser or water cut is the next level, I wanted to do it all myself first, that way I know it can be done.

[@JoseSilveira-newhandleforYT]

@@mike-M0MSN Absolutely! And as you got the prototype running very smoothly, it can only get better :-)

[@johndoe-bq1xt]

THANK YOU !

[@mariepi]

Possibly you can do the same with copper sheet or tin plate, with the advantage of being able to weld them

[@Dr._Spamy]

Aluminium is know for not making very good conductive connections. Even to let the protective foil on it won't help with this problem. On the other hand - most of this variable capacitors are made from aluminium sheet metal. But with somehow riveted brass spacers, I guess.

[@ianide2480]

apply contact adhesive to the printed parts and stick aluminum foil to those?

[@laxmikantpattar7096]

Wow supper

[@mike-M0MSN]

Thank you! Cheers!

[@jonyy3429]

Shoutout to Mainville

[@HeinSchlauHeinSchlau1234]

That is great! Thank you for this Video

[@mike-M0MSN]

You're very welcome!

[@omsingharjit]

similar story for me for 2 to 5 pf and veri cap availablity in my country either unavailable or Extremely expensive i want to buil my own but kind of smd type .

[@TheNoCodeTech]

Very helpful man, thanks

[@mike-M0MSN]

Glad it helped

[@markg6jvy135]

Nice build Mike 👍👏👏

[@mike-M0MSN]

Thanks 👍

[@wfwtheradioguy3414]

Nicely done.

[@mike-M0MSN]

Thanks! :)

[@danielpincu7743]

Hi! Wonderful job you've done! A quick question thought... Isn't going to too lossy for a magnetic loop antenna? It wouldn't be a good idea to weld the plates together to form a one block? The same for the rotor and stator.

[@flapjack9495]

There are a number of things that could be done to improve the Q of the capacitor here, but a lower Q might actually be somewhat beneficial in that it would make the normally-stupidly-sharp tuning of a magnetic loop antenna less sharp. It all depends on exactly how poor the Q is, really.

[@coltronex]

All I can say is very well done!From Colin,G1PGI

[@mike-M0MSN]

thanks Colin

[@stevek5416]

The protective covering on the "al-you-min-ee-um" as you say, is going to give you a little capacitive bump due to the dielectric effects. Don't know how much (or if it will even be noticeable). I would say that you did an excellent job of achieving your goal for a very high Q cap at a very low cost. What cap value were you shooting for?

[@mike-M0MSN]

Yes will be removed before use.. :) and 200pf so one or two more fins.. :)

[@stevek5416]

@@mike-M0MSN - Depending on the voltage that it will carry (power), you could also use shorter spacers between fins.

[@peasant8246]

@@stevek5416 I was about to comment the same thing: 3,5mm spacing between fins is a lot. I would've tried to limit it to ~1mm.

[@pietrogazzera5733]

Very well done!

[@mike-M0MSN]

Thank you very much!