Wayne,
The UPS shippable Rohn 9H50 push-up mast has a maximum usable length of
34 feet. For a tri-band yagi, you need to look at a surplus AB-577 mast
or a regular triangular tower with a proper base. The push-up simply
will not hold up under that kind of loading at the top under severe wind
conditions.
I have a 9H50, but only use it to support a dipole, and it's held up
well in Illinois winters and winds gusts in excess of 60MPH even during
icing periods. However, it's only up 25 feet with a proper concrete
base, bracketed at 8 and 16 feet, and no guys. But, I wouldn't put any
aluminum on the top of it for a permanent installation. It's a great
support for dipoles and slopers in a permanent installation, but not for
HF beams.
73
Don Allen W9CW
/My first project is to get a tribander (10, 15, and 20m) up and on the air
as quickly as possible. I have selected a ROHN 9H50 telescoping mast that
extends to 50' and has guy mounts at 4 locations up the mast. ROHN
recommends each set of guy wires start at 30' from the base of the mast. I
have bought a pair of Chicago Grips for tensioning the guys and a LOOS
tension meter for setting the guy wire tension to 10% of its maximum
strength.
/
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|