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[TowerTalk] 80m 4-square materials

Subject: [TowerTalk] 80m 4-square materials
From: Dennis OConnor <>
Date: Sat, 16 Dec 2006 08:25:47 -0800 (PST)
List-post: <>
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:

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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