Everyone seems entrenched in building antennas from .058 wall drawn
aluminum. Ask about .065 wall extruded tubing next time you talk to your
supplier. It is common up here in Canada. The extruded process produces a
less precise tube but one that is plenty good for antenna applications, at
roughly 1/4 the cost of drawn. Compared to the prices that N9EN relayed,
some sizes are about 1/8 the cost. Plus you get an .007 thicker wall. With
all the money I saved, I bought a hydraulic gin pole......
I use 6061T6 (it's the only alloy my supplier lists) x .065 wall extruded
tubing for all yagi elements and mix and match with pipe for larger
elements. There is no need to have elements that telescope (i.e. 058
all) - one can design strong and inexpensive elements with this material.
For the tubing sizes up to 1 inch, it is simple to drill out the first 4
inches or so, so that you can insert the next element. I make it tight
enough that a rubber headed hammer is used to forcibly join the sections
(w/NoAlOx) and the joint is tight and rattle free, and I'm certain has low
RF resistance, now and many years down the road. No slitting the tubing,
compression clamps etc etc. I usually put a SS screw or two in just to be
sure.
73 Don
VE6JY
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