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Re: [TowerTalk] Tower Trailer Safety;maintainence

To: "Pat Barthelow" <>
Subject: Re: [TowerTalk] Tower Trailer Safety;maintainence
From: Jim Lux <>
Date: Fri, 14 Jan 2005 15:26:51 -0800
List-post: <>

You might want to talk to Michael Tope ( or Marty Woll (N6VI) about CalTech ARCs tower trailer. It has outriggers, a crank up tower, etc.

At 11:04 AM 1/14/2005, you wrote:

I am refurbishing a State Highway Department (Caltrans) floodlight support trailer for re use as a ham radio tower trailer. The trailer has a HD Tristao 60 ft tower, with two motorized pivot (to vertical) and telescoping (3 20 ft sections) cable drives. The trailer is weathered, but inspection shows only localized surface rust of parts of the frame and erection fixtures. I want to clean up and paint, possibly repair gavlanized surfaces, and replace lifting cables. There will be a generator mounted aboard, and cabinets for equipment storage. The tower is in excellent shape and has a HAM 4 rotator. The trailer has two pivoting outriggers that are simple pipes, angled to the ground with footing plates, and a turnbuclke cable to bring the outrigger foot to bear pressure on the ground. Pictures exist for anyone interested in discussing improvements, safety issues. I see no locking features for each section, when extended. How can this be made safe? Is it safe to climb to each joint, and insert a block?

For the CITARC trailer, you shove a bar in across the tower section to prevent the tower from retracting, then crank it down onto the stop, so the cable hoist isn't bearing any load. Hardly a fully engineered solution, but it seems to work.

The CITARC trailer uses square steel tubing for outriggers.
has some pictures of the trailer. In some of the pictures you can see the outriggers; take a look where the tower is being winched up vertical.

I am reading case histories of crane and tower accidents on the web, and have found a number of crane accidents (often fatal) that were caused by crane outriggers failing for a variety of reasons, often by putting more than allowable PSI on the ground, resulting in earth shifting, unbalancing the crane, and causing collapse. Or outriggers that were not of sufficient radius to ensure stability. Not wanting to experience this firsthand with the tower trailer, I want to learn more about outriggers, scrutinizing the adequacy of the two existing ones at the rear of the trailer.. The trailer is only a single axle, is about 18 ft front to rear, approx 7 ft wide, and
the tower is very close to the rear, when vertical, with the two outriggers, about 15 ft long, pivoted and producing a triangular footing comprising the outriggers, the road wheels, and the trailer tongue screw jack.
Hopefully the ascii char drawing comes out OK below...
I am looking for feedback wrt safety issues, and surface rust refurbishment techniques..

I did some quick calculations on overturning for a tower attached to a car, and the quick thing is that if the wind comes up, your in a heap of hurt, even with a tower trailer, unless your outriggers are comparable in length to the height of the tower.

Try this:

Jim, W6RMK


See: 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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