HAM RADIO: MAG-LOOP Project: Making the Trombone Capacitor.
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- Опубликовано: 16 окт 2024
- No special tools needed, just pipe cutters and a blowtorch. simple build trombone capacitor.
MAG-LOOP Project: Making the Trombone Capacitor.
15mm copper pipe
22mm copper pipe
20mm conduit (plastic pipe)
4 x 15mm couplers
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Many thanks
Mike M0MSN
People tend to get hung up on what others have done and can they do it the same way - "do I need a lathe?", "I don't have those exact materials". You've shown that it can be accomplished with simple materials. Nicely done. I have pretty much the same loop as you (for 20 - 40m) and when I need to drop down to 80m, I switch in an 80mm x 100mm unetched double sided PCB in parallel with the cap, and I can tune across the band. Efficiency is probably terrible, but I can at least listen. Can't wait to see the end result.
Yep.. Thumbs up
Good work Mike!
Cheers Time
Another great reference video....cheers
Roly :)
Thank you.
Welcome!
Briliant! Absolutely Brilliant.......
this is a good idea to make a simple and cheaper capacitor..what should I do if I need to make a capacitor for more than 100 watts?
Increase the space between the plates or use a better isolator so that there is less chance of a flash over.
Hey Mike, this is a great little antenna you built. I didn't see it in action yet or I may have missed that video. Thanks for sharing. 73 Clark KG7LOI
Ok, so that is a lot simpler to build than cutting stuff on a lathe. Waiting to see how you motorise the trombone.
Brilliant! I'll have to go round the DIY store now and see if I can source them here too (Budapest) everything is at least metric so I might be lucky. I might have a go at making a steam punk manual antenna tuner! © 2020 😁😁😁
Hi Mike,
You sure did make it look simple. Looking forward to seeing the loop in action. Stay safe. 73 WJ3U
Cheers Don
Cheers Mike great information 73
Cheers Andy
This is great info about the correlation between the various pipe i/d & o/d and the couplers suitably taking up the last gap around the 15mm. My only question is what is your final Q like for the finished loop (ie how efficient/lossy is the plastic pipe as a dielectric?). The reason I ask is that I tried 2 copper plates 6mm apart and slid a sheet of glass in & out to vary the capacitance by changing the dielectric constant. The measured capacitance changed beautifully but the final loop Q was crap as although glass is a good insulator it was still too lossy at HF to make a good var-cap. I think teflon is a good low loss insulator and think the loaded grey PVC pipe is rubbish but the white stuff you have found, is it good or bad?.
All good questions, It seems to be working well....answers in the next video..:)
Very nice video, I enjoy the way you build your magloop.
Excited about your next tudorial...
Vy 73 de Stefan DG4RBS
Thanks. :)
Hi Mike another great video. You certainly make it look so easy and the fact that you could use readily available materials is just iceing on the cake. Have you thought about making these capacitors a little smaller by stepping up the pipe sizes to 28mm? This should make them a little smaller. I'm currently experimenting with 28mm and 22mm and 15mm pipes. So far so good 95pf with 10cm lenght. I will let you know how it works in practise once it is soldered togeter. Have you experimented with any other diameters?take care
Sorry i didnt make it clear in my previous post the 95pf on 10cm lenght is just one half of the trombone so the full trombone would be half of that.
I will have to give it a go. :)
Nice going Mike.
Cheers Roly...
You need to put the center sleeve on the inside conductor so you have full adjustment without rattle...!!! 😊
Good tip!
awesome video! I have been looking for an alternative to air variable capacitors (which are really hard to come by) and I think your idea is great! How much power can the trombone handle?
Around 100 Watts
Very nice 👏👏
Thanks 👍🏻
The project is very interesting, please can you tell me where to buy the plastic pieces to hold the tubes, thank you very much
Check description, DIY Shops everything is from DIY.. :)
The minimum of the capacitance is key. What was it?
Mike 👏👏👏👏👏👏👏👏
Thank you..:)
Did u make any spark "test"? How many KV or RF Power can u go? TNX and have fun! Great project. Like! Keep on moving!
No Spark test...
@@mike-M0MSN how many kilovolts can this take? I assume i'll have to build longer ones in parallel, but I don't know starting limits...
I suppose then the stationary parts of the capacitor are part of the loop length?
Yep, spot on.. :)
you should consider selling these as kits?
One day maybe
I'd buy one.
Cool! Wanna see your mag loop in action. 73 PY5WHO
Why not get a few syringes and pipe to make it hydraulically move. That way you can operate it remotely and still be able to tune it without having to manually touch it.
Great idea
hreat video
Thanks Craig
@@mike-M0MSN i got the local Texas dias, how about length i am in very unknown country right now
you might have explained the relevance to the main project.... and then its application (it`s not obvious to everyone)
Sorry Gabriel, :(
@@mike-M0MSN ur forgiven
i like the trombone but my trombone gets rusty so a now call it a rusty-trombone,,
lol