I have heard from a reputable tower installer that the insulated Rohn sections
using ceramic are prone to cracking, especially if the guys are not tensioned
properly and equally during installation while working up to the appropriate
tension setting. He has insulators made from stainless steel cups and delrin
plastic. The delrin is turned on a lathe to fit in the cups, forming an
insulator with about 2" of space between the stainless cups. The cups are
about 5" in diameter and about 6" long assembled into an insulator and have
inserts made of stainless welded to the cups for the tower legs to sit into.
Basically, once assembled, the insulators simply sit on top of one section then
the next section sits into the insulator. No bolts. The ones I saw were used
just above the feed point at about 20' on a full size 160 meter vertical with 8
elevated radials. The supported 120' of 25G plus the tuning mast on top.
Rudy Marcelletti, K8SWD
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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