Digikey Order (for the high power version)
Attached is a Digikey Part List that you can use for the higher powered version. These capacitors go up to 560V, which allows you to use a ~500W amplifier, and get up almost two feet of range. The attached version only includes the bare minimum parts. As long as you’re making a Digikey order, order some extras in case you make a mistake or blow one up (that’s particularly true of the TVS protection diodes, which I smoked several times).
Step 2: Make the Coil Winder
In order to wind the coils, you need a frame to wind them around.
On a piece of plywood, you need to use a compass to draw out a precise 20 cm circle and a precise 40 cm circle.
Hammer nails evenly spaced around the circle. For the 20 cm circle, I used around 12 nails and for the 40 cm circle, I used around 16. At one spot in the circle, you’ll want to make an entry point that will hold the wire while your beginning the first winding. At that spot, hammer another nail close to one nail, then another a couple inches away.