My first thought is 3 sections of 20G tower guyed at the top and setting on
UHMW pads. Then 3 sections of 10 foot long schedule 40 aluminum pipe in
decreasing diameters... You will need to shim them to fit together with ~1/2
foot overlap and have them MIG welded into a single 29 foot piece... If you
make the two step down diameters far enough apart you can have a machine shop
bore a sleeve to join each section properly without fiddling with thin sheets
of flashing, etc., or with bending thicker pieces for shims.. Say 3" to 2" to
1"... I'll let you look up the sizes and play with the ratios...
There are other ways to shim without machining, using rectangular tabs with
bored holes and welding through the holes... Homebuilt aircraft fabricators
will know how or you can call me and I'll explain...
Here is one source for pipe schedules:
http://www.easternmetal.com/products/pdfs/standards/aluminum-pipe-extrusions.pdf
Anyway, this will leave you roughly 58"-4" tall and shy of resonant and a 0.5"
tip extension and/or capacity hat will walk them on to frequency...
denny / k8do
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