[TowerTalk] raising fixtures

[Robin Midgett]

I worked a solution for my situation. I generally have to do my tower work 
alone, atop 130' of Rohn 45G.

I built a mast raising fixture that works great for a "one man" job. It 
consists of a worm drive steel cable winch which fastens to the tower (Rohn 
25G or 45G or 55G) via a small steel frame with U-bolts, and pulley on a 
yoke which supports the mast at its bottom. The winch mounts to the tower 
near the top. The steel cable extends from the winch down inside the tower 
& under the pulley/yoke assembly & back to the tower top where it hooks 
onto a tower rung, opposite the winch. There is a bolt on the yoke to 
tighten in against the mast to keep the mast from rotating inside the 
yoke/pulley assembly.
The operator has to simply crank the winch to either raise or lower the 
mast. With as much mechanical advantage as the system has, raising a 4130 
Chromoly mast loaded with antennas & feed lines is no problem. Plus, it 
stays put in any vertical position due to the worm drive, no braking 
mechanism needed. It also stays vertical (mostly) when being raised or 
lowered since the cable is strung under the mast & is cradling the system.

I use a shaft collar on my mast to keep the mast in place vertically; the 
shaft collar rides on top of my TB-3 thrust bearing. Each time I raise the 
mast, I lower the shaft collar to its new position. The bolts in the thrust 
bearing simply help center the mast in the tower. I never have liked using 
horizontal bolt ends to keep a vertical mast from sliding downward; 
personal choice here.

I made a "T-bar" that fastens to the tower legs to keep the mast from 
tipping over when it gets to gets to be more than half way out the top of 
the tower. There is a U-bolt through the T-bar which the mast passes 
through. When the mast is raised, is slides through the U-bolt on the 
T-bar, then I tighten the U-bolt, leaving enough mast below it to put the 
rotator clamps on & install the rotator. A second rotor shelf would 
accomplish the same thing; the T-bar is removable post mast raising, 
though, where the rotor shelf isn't.

My rotor shelf is also fabricated for the situation. It has only enough 
steel plate to accommodate the rotor base. It has spokes (1" square steel 
tubing) welded to the plate which are bored for U-bolts which attach the 
plate to the tower. In this configuration, the rotor plate can be placed 
almost anywhere in the tower AND inserted into the tower between rungs.

I have pics if anyone would like me to send them via E-mail. I plan to put 
them on a web page...someday.
I am willing to loan the gear out to anyone willing to pay shipping both 
ways & a refundable deposit, just for insurance that the gear comes home 
since I have a fair amount of time & a small amount of money invested in 
the system. I have no profit interest in the mast raising gear.
The pulley and yoke assembly also doubles as part of a "zip line" for the 
nephews; 250 feet of 1/4" steel cable streched on an angle between the 
tower & another support in the yard; the kids love it!

At 10:30 AM 11/22/2001 -0600, S. Markowski Jr. wrote:

>Hi Larry, you can also check IIX Equipment Ltd, owner W9IIX (Doug).
>Advertises in QST and I believe CQ or:
>
>http://www.w9iix.com
>
>
>List Sponsored by AN Wireless:  AN Wireless handles Rohn tower systems,
>Trylon Titan towers, coax, hardline and more. Also check out our self
>supporting towers up to 100 feet for under $1500!!  http://www.anwireless.com
>
>-----
>FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
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Thank you,
Robin E. Midgett KB4IDC
IDC Technology
www.idctechnology.com
Metal Fabrication for the Radio Amateur
Distributor of Tower*Jack Products
615-773-4199



List Sponsored by AN Wireless:  AN Wireless handles Rohn tower systems,
Trylon Titan towers, coax, hardline and more. Also check out our self
supporting towers up to 100 feet for under $1500!!  http://www.anwireless.com

-----
FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com