Homebrew Inductors

[ka1tdq]

I'm sure that this topic has been covered before, but I need to make a homebrew air inductor using #12 solid copper. Tolerances are very tight and I need things to be very exact. Without using a center form, what's the material that will hold the turns by 'snapping into' the wire and you use 4 strips to run along the 4 'sides' of the inductor. I've seen guys use them online but I don't know what they're called or where to buy them. I think they're made out of teflon or something like that.

Jon

[WB4AM]

Not exactly what you might be looking for but it may help.

[ka1tdq]

It wasn't quite what I was thinking of but will definitely do the trick!

Thanks!

Jon

[wa2fxm]

Maybe this stuff will work for you? AD5X has this article which says he used nylon edge trim available here: www.mcmaster.com. PN 85085K8, $10.50 for 25 12-3/4” strips. Apparently it's 8tpi and holds #12 wire. I'm looking for the same stuff but I need 6tpi. Haven't been able to find anything else that will work. Good luck.

http://ad5x.com/images/Articles/CoilRevB.pdf

Mark - WA2FXM
Vermont Sanderista

[WBear2GCR]

A hobbyist with a lathe or a machinist can take some PVC pipe and put "V" grooves
in the pipe surface at any pitch (number of turns per inch) desired. The benefit of
the V groove is that the wire can be smaller or larger, as long as it rides in/on the
groove.

"Square grooves" (aka "Acme threads") are also possible.

You can drill some holes for the terminations and/or to capture the wire and then
apply the wire around the grooved form...

FYI.

                    _-_-bear

[ka1tdq]

That's what I was trying to find! Eight TPI should do fine. Thanks for the purchasing info too.

The winning design for my situation appears to be another 8-FET rig. I plan to fit it into the aluminum enclosure pictured in the equipment housing. To make everything super RF-tight and make everything fit, I need to run the plexiglass shaft for the tuning vacuum cap directly thought the center of the output inductor. To do that I need make my own coil with a gap in between.

PVC will work at 75 meters fine, but I'd just prefer not to use it. Plus clearances are small with this rig.

The second picture shows the layout with RF shields and everything. The phase splitter and duty cycle adjuster will need to be mounted on top of the chassis in its own small enclosure. I'll cheat on the VFO at this point and go to the Chinese standby.

Off topic, ACDC just came out with a new song and its a good builder-to.

https://www.youtube.com/watch?v=54LEywabkl4

Jon