[Towertalk] TX-455 Project Questions

Dana Roode K6NR@ARRL.net
Fri, 21 Jun 2002 20:19:10 -0700


TowerTalkans --

I'm planning my first tower, a US Tower TX-455.  My building permit was
approved today, so Im about ready to order the beast.  Some questions if
anyone would like to share the benefit of their experience with me.

I would like to put a Force12 C3E (5.8sf windload), a D3W 30/17/12 rotable
dipole (.9sf), and a small 3 element 50mhz beam (1.8sf) - a total of 8.5sf. 
This is below the 70mph rating for the tower.  I havent added in a value for
the mast.

a) Im allowed a height of 65', or 10' of mast above the tower.  Is this
enough to space these three antennas, or will there be serious interaction
problems?

b) What length mast do I want to have 10' above the tower?  Im asking what
the distance between the rotor shelf and the top of the tower is
essentially.  Is the rotor shelf in a fixed location or can it be
raised/lowered?

c) Do I want to use one of USTower's "reinforced" masts?  They have steel
inserts in the bottom half.

d) Do I want to use a thrust bearing?  I assume Yes.

e) It would seem logical to put the largest antenna, the C3E, at the bottom
of the mast, with the 6 meter antenna in the middle, and the 30/17/12 dipole
at the top.  Could I get away with reversing the order and having the C3E at
the top?  Its the one Id like the highest.  Im guessing this is a bad idea.

f) US Tower sells a mast raising fixture to help pull the mast up.  Is this
essential?  I assume it depends on what is on the mast and I dont think a
D3W and 6m beam will be very heavy. 

Thanks for any responses.  And yes, I can also ask US Tower some of these
questions, but Id like to hear from others as well.

  Dana