[Antennas] Fold Over Pole

[Mike Gilchrist]

At 01:49 PM 6/9/2002 -0500, Richard Biddle wrote:
>Once upon a time I had some plans for a good reliable fold over antenna
>pole.  I want to put up a small set of VHF/UHF beams and a CD44 rotator at
>40 foot or so.   I have access to free pipe and a gentleman who welds for a
>living.  I can't find my plans ...

Richard:

I've had a foldover of my design planted for several years now.  It is 
quite a simple project actually.  Not quite the 40' you've stated, but 
close; my 22 element 2M and 40 element 70cm antennas, with a Yaesu az/el 
rotator have stood the test of time in stormy SW FL.

I built the entire tower on the ground, dug the hole, and had several hams 
wrestle the 300 pound monster into the ground, where it was cribbed with 
2x4s and stakes, while 600 bs of concrete cured for a week.

The tower is comprised of 3 4x4s around 22' in length.  Two of them are 
planted in the ground 3 feet, while the third pivots from near the top of 
the stationary posts, on a stout stainless bolt, washers, and double 
nuts.  A similar "pin" is pounded through all three and washer and nut 
placed to hold the tower from folding.

A 20' length of 2" schedule 80 galvanized pipe is mounted to the center 
timber and gives additional height.  A large eye bolt is fastened through 
the bottom of the center timber to hold a counterweight used when the tower 
is lowered.  I bent some rerod into a loop and put it in a 5 gallon bucked 
sprayed with Pam.  When the concrete set, it pulled out of the bucket with 
ease.

So standing in front of the tower, it looks like this:

         Two 4x4s set 3 feet into the ground, standing 19 feet high.  A 
middle timber is pinned between the 2 stationary timber at about the 3" 
level, and again at the 17" level as the foldover pivot..  The middle 
timber sticks above the 2 stationary ones by about  6 feet, putting it at 
around 25'.

         The 2" pipe is fastened to the middle timber with 3 large 
stainless bolts, washers, nuts, 90 degrees to the pivot.  The pipe sticks 
up about 10 feet above the middle timber, to about 35'.

         A large eye bold is fastened through one of the stationary timbers 
to thread a rope for lowering the tower.

To lower the antennas/rotator, I fasten the counterweight with a short 
piece of rope to the eye bolt on the movable timber.  I fasten a long stout 
rope around the 2 stationary timbers, through the stationary eye bolt and 
to the same eye bolt as the counterweight is attached.

I remove the lower pin by removing the nut and washer, and pounding it 
through with a similar bolt.  You definitely want a snug fit on this pin 
and the pivot bolt.  I pay out the line while watching the antennas and 
having someone inside manipulate the rotor control.

It works great, but if I ever build another one, I will substitute one of 
those reconditioned Rohn push up poles you see at the hamfests for the 
entire center timber/pipe assembly, and let it pivot between the stationary 
4x4s.

One of the hardest things I've found is finding the position on my 
horizontal mast that equates to the antennas being level, once I hoist them 
back into the air.

I used to use a come-along to hoist the tower back into position.  This 
took at least half an hour and caused me to go through several tiresome 
machinations.  I now fasten the rope to my trailer hitch and "drive" the 
tower back to the vertical.

I hope this is of some help.  I make no warranty as to the suitability of 
this design for your application, but has helped me to work over 100 
countries, as well as MIR with my Oscar station.

73, Mike kf4fdj