I've actually done something similar when I was a kid but I used a paper towel tube and a sheet of copy paper as a dielectric instead of pipes.

Thanks for the video. I followed your design with a few exceptions. I used 2 paper towel cores. I split one core and then cut off about 10mm / 3/8" along the same split cut so that core could be squeezed together smaller to slide inside the outer core. Your bigger diameter thin wall PVC might have given me greater pF as my end result. I slid my smaller core inside the outer core and taped it so it wouldn't expand Then I took out the inner core and wrapped it all the way around and the full length of the core with one piece of foil and then taped the foil. Then I wrapped the outer core with foil all the way around and full length and taped it. I taped my wires to the foil much the same as you did. My end result was 200pF. There's two things I'll do different if I make another one. That is to wrap more foil around the inner core so it will fit a little tighter and increase the capacitance because of closer proximity of the two sheets of foil. The other thing is leave 50mm to 80mm / 2 inches to 3 inches space at the end I'll hold to push / pull. That's because hand capacitance aggravates the tuning. I've watched a lot of your videos. Thank you.

Chilled video Peter! DIY neighbours and those birdies! Your knees must hurt tho! Thanks

I used a cardboard paper towel tube with one 6" square of foil, and a sheet of copy paper with one 6" square of foil around it with enough paper exposed at one end of the cylinder to hold it for sliding across cardboard tube. With just the paper as the dielectric I usually get over 1200 pf. The printer/copier paper worked for 7 watts CW on a mag loop. Next time I will try a tube with a smaller "trimmer" cylinder for fine tuning. I found that rotating while sliding makes for smoother tuning of smaller increments, preventing the friction skips and jumps.

This vid could have done with some tight editing.

This reminds me about Mr Villard's loop. The advantage of that was that the capacitor is integral part of the loop antenna and did not need wire connectors, since it was inductively coupled with the receiver. I wonder if anyone tried transmitting with Mr. Villard's antijamming loop.

Now that's granular control of a small value of C. Wonder what the breakdown voltage might be? If really high, would this not make a super easy to adjust mag loop cap? God I'd love to visit your magical land someday. Thank you for the wonderfully interesting and really creative ham videos! 73 OM

Good Job, Im About To Make One Myself From Two Pvc Tubes, But Much Smaller Then You Made :)

Can someone help me to know why my magnetic loop is increasing the static of the MW frequencies rather than reducing?

Is this the same idea used in so many homemade 11 meter cb amp videos I see being used as a tuning capacitor for input or output tuning???? See them in BBI Amps videos all the time. This looks like those copperish looking ones he uses. What amount of rf power can these hold up to if used on rf amp output side??

LOL, the connecting wires for this ginormous capacitor will have too much stray inductance for HF purposes.

What's an experimenter without teeth to cut with or toes to clamp his work in place! Aside from the total "plate" surface area, the two most important variables for a capacitor are the spacing between the plates--in this case the thickness of the outer tube (plus whatever clearance there is between the inner and outer tubes)--and the dielectric constant ( _k_ ) of the material(s) separating the plates--here, PVC and a little air. The closer the plates the higher the capacitance. The greater the dielectric constant the higher the capacitance. Air has a _k_ of slightly more than 1.0. PVC is about 4 (and other common plastics close to that). Glass can be as high as 18. Ethylene glycol (antifreeze) is 37. Distilled water has a _k_ > 80!

you know peter you could have used good Aluminum foil tape instead of that thin Aluminum kitchen foil.

That one strange sounding bird!

Double sided tape may make a tighter flatter fix

Interesting sounds in the background. Nice video.I have all your books

Can we use this capasitor in radio tunig

Probably using aluminium or copper tubing would produce better results and make entire thing more sturdy.

What are you going to do with it?

Deve prima costruire un tavolo dove lavorare