[UK-CONTEST] Guying....

[Ken]

Talking to Ian VK3MO recently who passed on information on the guying 
that he uses and is (briefly) as follows:
132ft Rhombic (!) support towers in service for 25 years using 8mm 
diameter double braided polyester rope.  This is one rope inside another 
with the outer protecting the inner.

200 ft rotating tower (supporting a 4 x 5 ele stack for 20m so that's 
why Ian is stronger than most other VK's!) has been up for seven years, 
has survived several 100mph storms uses 14mm diameter rope with a trade 
name of Super Braid.  (good, but not cheap available in the UK? ).  This 
has a similar elastic elongation to wire rope and is stronger than a 
wire rope of comparable diameter.

A previous 200ft rotating tower was guyed with 12mm diameter double 
braided polyester. This tower failed in a mini cyclone, not because of a 
guy failure but because the tower cork screwed and detached at the 100ft 
level with all the guys still attached. (ouch!)

Maybe there's a clue in the last sentence and which may have already 
been suggested, the upper sections of crank up towers
aren't strong enough for the head load which they are being asked to 
support.  Looking at the pictures of Ian's tower on QRZ.com shows that 
it's much more substantial than most crank up towers but has the 
disadvantage that maintenance requires climbing the 200 ft. tower 
(providing you don't mind working at height that would keep you fit!)

Hope that's of some use to those with big towers, the rest of us can 
only be jealous!

73...

Ken

G3LVP