[TowerTalk] ...Compressed Air Driven Tower

[Roger Parsons]

I have three of the ex UK military Clark 'Scam' 40'
pneumatically operated towers. Whilst I agree with the
caveats from Ian, GM3SEK, I have actually found them
pretty good for fixed operation even here in North
East Ontario.

(1) I managed to find a whole load of new seals at a
flea market. These make all the difference in the
world. Mine will now stay up for at least a week just
on air pressure, but of course the sections should be
locked and the air pressure released anyway.

(2) The pressure required is quite small - about 20
psi, and the military used a stirrup pump. Need some
pretty good strong squaddies though if there is any
weight on the top! I use a small compressor.

(3) They have a drain hole at the bottom which can be
kept open. This does seem to work in allowing the
water, which will make its way past the seals, to get
out without causing damage.

(4) There are two versions of the Scam masts. The
earlier ones have a major design flaw in that the top
section is constructed like a 5' long cup! The
solution is to (carefully) drill a drain hole, and
fill the part of the tube below the hole with
expanding foam.

(5) They will support quite a weight. One of mine has
a rotator, 10' extension and an A4S on it, with two
sets of (4) guys. A second has 45' of tubing/whip on
top and 3 sets of guys. The third has 20' of tubing
and a 900MHz antenna on top. The first two have been
erected here for 7 years, had been up for 5 years in
England, and are lowered (easy) each year for
maintenance. So, if they are properly prepared and
guyed they will withstand pretty high winds (UK!) and
pretty cool temperatures (Canada!).

I am not suggesting that this sort of tower is a
replacement for the steel lattice type. They do
however have considerable advantages, as they can be
erected with no site preparation, no concrete, single
handed, and removed just as quickly.

73 Roger
VE3ZI/G3RBP





	
	
		
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