Get a 1 foot length of 1 1/4 inch PVC Schedule 40 pipe
which will fit loosely over the 1 1/4 inch aluminum.
Saw four lengthwise slits a few inches long in one
end, at 90 degree spacing around the PVC. Clamp
this to the aluminum with a hose clamp.
Repeat above using 3 inch PVC Schedule 40 pipe which
will fit loosely over the 3 inch aluminum.
Use standard PVC plumbing parts to connect the 1 1/4 inch PVC
pipe to the 3 inch PVC pipe using PVC pipe glue.
Jumper around this plastic assembly with a piece of
aluminum wire clamped to the aluminum tubing with
hose clamps. This provides electrical continuity.
I built six 40 meter verticals this exact way (except
the stinger was 2 inch aluminum).
Note that the aluminum is inside the PVC in both cases,
and you do zero machining of the aluminum.
Rick N6RK
On 6/8/2019 9:08 AM, Jeff Blaine wrote:
I'm rebuilding my 40m 4-sq verts and have some 15' lengths of 3" OD/
2.75 ID tubing to use on the base end. And for the "stinger" end, I
have some tapered elements off an old yagi that are 1.25" OD on the
bottom of the 17' length.
Other than buying some concentric lengths of aluminum to step from the
1.25 OD stinger up to the 2.75 ID base tubing, any good ideas of an
interposer that would take up some of the space?
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
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