See https://www.thingiverse.com/thing:4277687 to download STL files.

This design includes a bottom support that accepts banana plugs to make tapping the coil easier. The inductance of this coil measured by my inexpensive component tester is 40 uh.

The supports are designed to slip over a 2 inch piece of PVC pipe and glued in place. Pipe fittings can be glued into the ends of the pipe to allow attachment to the antenna mast and whip.

The coil supports are numbered on the ends and should be arranged counter-clockwise around the supports as viewed from the numbered ends. This will allow the coils to be wound in a nice spiral. The supports are 100mm in diameter (about 4 inches) and the assembled length will be around 150mm (about 6 inches). The spiral is 4 turns per inch and the grooves should accommodate 14 or 12 gauge wire.

At the feedpoint of the antenna I used a 1 uh matching coil as detailed here: http://www.k0bg.com/match.html

There are 11 parts to print: a bottom support that accommodates banana plugs, a mid and upper support (same file) and 8 wire supports. Each wire support is different and should be arranged as noted above.

I created an earlier version that's 6 TPI with a calculated induction of 100 uh. See https://www.thingiverse.com/thing:3848128 for details.