[TowerTalk] Homebrew Crank-up

[Steve, W3AHL]

The rollers are probably the least of your problem, but for a typical solution, see the video at:

http://www.intelcotowers.com/video.htm

Pause it when they show close-ups of the rollers.  They use two shaft mounted rollers in a u-channel at the bottom and top of each leg tube.   Something similar to:  http://www.mcmaster.com/#guide-rollers/=6euwew   would work.  The main concern would be static load rating and weathering.    A stainless steel grooved sleeve bearing and shaft might work also, if lubricated frequently.   

You would need rollers rated for at least 20,000# static load (assuming two per channel).

The challenge is to maintain tight tolerances on leg straightness and spacing so the telescoping sections are loose enough to not bind when under a significant wind load and yet tight enough that the top section doesn't deflect excessively during gusts.   Powered pull-down would be required.

This is less of an issue with shorter nesting section that with a single 75' section.  55G won't handle the wind loading unguyed and would bend too much to allow it to retract reliably.

Steve, W3AHL

Date: Sat, 27 Mar 2010 17:15:12 -0500
From: Stan Stockton <k5go at cox.net>
Subject: Re: [TowerTalk] Homebrew Crank-up
To: "Tower and HF antenna construction topics."
<towertalk at contesting.com>

As mentioned the lower section would be large (33 inch face) tower  
with 3 inch diameter legs.  The top would either be 55G or 65G.  I'm  
interested in ideas for rollers, etc.  Not worried about whether it  
will stay up or not.  There would be guy wires on lower section.

Stan, K5GO