Brutkey

Michael K Johnson
@mcdanlj@social.makerforums.info

For my #HamRadio tunable elevated radial project, I want to isolate them from the earth and the mast, and I'm not finding an isolating mount that goes into a normal ½" "light stand". So I've come up with this design to build. (Yay, I can't just buy it, so I have an excuse to spend some shop time!)

From 1" 6061 aluminum stock and 1" POM:
An aluminum stem/spigot that fits the tripod, with a 1" section above. In that section, an M14x1.5 threaded socket.
A POM threaded bushing; M14x1.5 on the outside, M10x1.5 on the inside, with a 2mm flange on top
An aluminum piece on top with M10x1.5 screw threads on both end, and six 4mm holes drilled around it to accept 4mm banana/bullet plugs. The M10x1.5 is to match the JPC-12 feed base.

I intend to raise only two radials, but six holes give me a chance to change my mind later, and even with just two they make it easy to line up the holes well enough with where I want the radials to run. (An elevated radial is worth about 8 ground-coupled radials.)

My idea is to machine the POM threads a little over-size, so that the whole thing is hard to screw together and locks together kind of like a nylon locknut. The larger diameter of the aluminum pieces will be knurled to facilitate this. It's meant to be strong enough to hold as much as 30 feet / 10m of loaded vertical, including JPC-12 riser sections, JPC-12 loading coil, and up to 25' whip.