Topband: Vertical construction

Mon Jan 9 06:00:50 EST 2006

Date: Mon, 09 Jan 2006 05:12:34 +0000
From: W5UN <w5un at wt.net>
Subject: Re: Topband: Vertical construction

For what its worth ---

I constructed my verticals using 5", 0.050" wall irrigation tubing, from
top to bottom. The verticals are 140 feet high. The top section is 120
feet, made from three 40' lengths of the 5" tubing, and spliced with the
same 5" OD stock that I cut 36" long, and then cut a full lengthwise 5/8"
slot (using a dado on my bench saw) to permit squeezing the piece together
so that it slips inside the two sections being spliced. I then secure each
splice section using 16 self tapping #8  - 1/2" long SS screws

The bottom 20 feet is made from the same 5" OD tubing, and serves only to
raise the base of the vertical to the 20' level. A 36" long piece of
modified 4" PVC pipe or conduit is used to splice the top 120' section with
the bottom 20' section. Since the 4" PVC conduit is not quite large enough,
I modify it by cutting two 36" lengths of 4" PCV sewer pipe, then split
them on one side using my table saw. The first piece is slipped over the 4"
pipe, and the second piece slips over the first, making an insulating
section that is just right diameter to fit inside the 5" irrigation tubing.
a 2" insulating gap of PVC is left exposed between the top 120' long
section and the bottom 20' section. The insulating splice section is
secured to the aluminum tubing using four 6" long 1/4" galvanized carriage
bolts, lock washers and nuts.

Four sets of 4-way guys are attached, and the entire 140' length is pulled
up using the "falling derrick" method. The derrick is simply a single
length of 4", 0.050 wall aluminum irrigation tubing that is 40 (yes, forty)
feet long. 2000' of guying is required for a single vertical of this type.
all four guys on one side are attached to the derrick. I prefer the
Dacron-Kevlar material for this since it is quite strong, UV resistant, and
has very little stretch. 1/8" OD works just fine. The guys are attached
using a 6" full stainless steel hose clamp at each of the four guy points
on the mast. If you want to attach guys this way, 3/16" ID clear neoprene
tubing should be slipped over the guy line where it fits under the hose
clamp, in order to protect the guy line from being damaged by the top edge
of the cable clamp. I make a horseshoe shaped loop of the tubing with guy
line running through it, and secure the line with a BOWLINE knot
(important. If you don't know how to tie this knot, then learn!). This
gives a fisheye loop that can be secured with the cable clamp.

All materials except guy line and aluminum tubing is available from Lowes
or Home Depot, Marine grade all stainless steel hose clamps are available
from www.PlumbingSupply.com.  Guy line is available from The Radio Works.
Aluminum tubing is available from Hastings Of Nebraska, who manufactures
irrigation tubing, and will truck deliver for $150 plus cost of tubing.
They know where my place is, hi.

By the way, the guys do not need to be real taunt. A little sway is not a
problem. The vertical will chatter from self resonance in the wind. This
does not seem to hurt anything, but you better have all electrical
connections well secured.

I have one such vertical in place that has been there for one year, and
through hurricane Rita (only 60 mph here though). The second went up last
Friday. The remaining two will go up before the end of January if all goes
according to plan. I purposely waited a year after building the first 160
meter vertical to make sure it would survive the elements before proceeding
with the 4-square project.

In addition, I have a 4-square on 80 using this same guying method and
material, and it has been up over two years.

If this description is beneficial, I have a few photos, and can help
someone who SERIOUSLY needs it.

73, Dave - W5UN						w5un at wt.net

homepage: http://web.wt.net/~w5un    Grid: EM23mg

RR 10, Box 27
Mount Pleasant, TX 75455		