"Angela & Gary" wrote in message
...

I am planning to construct a vertical dipole array for 20m. The
electrical calculations are complete (with help from LB Cebik) and now
I'm looking for some advice on the physical construction. I'd like to
use Al tubing and find unfortunately that this is difficult to come by
locally. I will likely obtain this then from Texas Towers and therefore
the tubing lengths will be limited to 6 ft each. They do offer nesting
sizes so the real question is what diameter to utilize for the lower
most 6 ft segment (dipole being some 34 ft or so). Recalling the approx
dimensions of commercial vert antennas I've had in the past leads me to
believe that 1.25" or so would be sufficient. Comments/advice ?? I
would like to do this without guys if possible and plan on attaching the
lower-most segments to 4x4's. Thanks in advance all.

Gary

Gary -

Here are some suggestions.

1. Texas Towers is a good known supplier, but you can also get 8 and 12 feet
lengths of 6061 Aluminum tubing.

2. I talked to Charles Penninger, KC9DAO (St. Charles, IL) last weekend.
He does carry 6061 aluminum tuning in the 8' & 12' lengths and can perform
custom machining -- if you require.

His "Clamp-It" series of mast clamps may be of interest for your design.
http://www.penninger.com/prod01.htm

His web site is just being developed
http://www.penninger.com/

3. DX Engineering has a number of appropriate parts (radio support block
clamps - up to 2" diameter), depending upon how you wish to construct the
verticals or attach them to a wooden 4x4.
http://www.dxengineering.com/default.asp?DeptID=6

4. Array Solutions - 41' monster
http://www.arraysolutions.com/Products/asvd41-fs.htm

5. Cal-AV Labs vertical antennas is an approach to study (full sized 1/4
waves)
http://www.arraysolutions.com/Produc...v_vfseries.htm

6. Don't forget a static bleeder choke
http://www.arraysolutions.com/Produc...surgecoils.htm

A 20 meter field day antenna
http://www.kn5l.net/fdantenna/

w9gb