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By David M. Sheaffer, KC8MAY
2568 CR 37, Lakeville, OH 44638
January 6, 2005
The idea for this tower started after a Field Day and I had encountered problems of getting an antenna up without having trees or other immovable objects that are always in the way. I wanted a light-weight tower that would be easy to transport and erect. Ideally, it should also be inexpensive and built out of readily-available building materials.
For my first attempt, I used sewer pipe and tried to assemble it in such a way that it would telescope by air or the exhaust of a vehicle. However, the available pipe was not of a tight enough tolerance as to be able to get the o-rings to seal in every random piece.
On the second attempt, I decided to
once again use the sewer pipe as it is lightweight and readily available at
most building supply stores. However,
this time I decided that I would construct a crank-up telescope. I started with a 4-inch schedule 40 plastic
pipe with a 3-inch pipe fitted inside of it.
For the third section, I fitted a 2-inch pipe inside of the 3-inch
pipe. A bit of machine work was
required, so I decided that I would make available a kit of these parts and an
assemble drawing. Therefore, anyone
wishing to build this tower would only need a hammer, drill & bits,
screwdriver, adjustable wrench and 2 taps (a #10-24 and a ¼ inch- 20).
Cutting the pipe to length and gluing together the bearing end and sliding it on to the 3-inch pipe starts the assembly. Next, glue the bearing end and slide it on to the 2-inch pipe. Once the glue has dried lay out the pieces and place the 3/16 cable through the pulleys and the end caps as shown in the photograph. In the fourth step, the insides are sprayed with a dry lubricant so that they will slide together easier. Then, slide all tubes inside each other making sure that the cable does not get tangled and is straight through all caps and pulleys. When all is lined up, place glue on the caps and tap them together. If desired, the assembly can be screwed together rather than glued.
A boat winch may be used to raise
and lower the telescope. This can be
mounted with U-bolts. Note: do not over
tighten the bolts or you will crush the pipe.
This completes the tower.
The finished tower weighs 34 pounds. When collapsed, it is 8 feet, 8 inches and it will telescope to 23 feet. The plastic pipe will handle a whip antenna, buddy poles as a dipole or a small center balanced structure such as a short inverted V. It could also be of value to ARES groups, for emergency use by Fire Departments and Police Departments. It could be used by farmers for auxiliary light out in the fields or other areas. Remember, this is a light tower and may find uses by many other groups or individuals for various reasons.
There are several options for mounting an antenna at the top of the tower. A coupling with a 2-inch to 1-inch bushing and a stub 1-inch pipe (10-12 inches in length) may be used with 1 ½-inch U-bolts.
To erect the tower I use a piece of
5/8 inch rod driven into the ground with about 4 inches left out of the ground
for the tower to set upon so as not to allow the bottom to kick out. I attach three guy wires 120 degrees apart
at the top of the first section to stakes driven 10 to 12 feet out from the tower. It could also be erected on a 2-inch square
into the hitch of a car with a strap placed from the pipe to the luggage rack.
