[HBR] Riddle me this!

[Walt Hutchens]

I've had very good results -- a couple of perfectly adequate HBRs --
using PVC water pipe from Lowes.  I think the 1" Schedule 20 (thin
wall) stuff is what I used; it fits snugly on an octal bakelite base
from a dead metal vacuum tube and can be secured with epoxy when
you're ready to do so -- best after doing the experimenting to get the
stuff inside the form just right.

I've never done a microwave oven test on this stuff but if you don't
have the front end peaked to perfection the receiver goes dead, so the
Q is certainly high enough.

The 1" is a nominal inside diameter: The O.D. is around 1-1/4" as I
recall.

I cut off all unneeded pins to make the coil easier to insert/remove.
A Dremel tool can be used to increase the clearance inside the top to
mount APC trimmers.

You can make a flange for the top from a slice of a PVC pipe slip
coupling.   When these turn out well they're just about
indistinguishable from commercial.

Walt
KJ4KV