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Re: [TowerTalk] Homebrew Crank-up

To: "Tower and HF antenna construction topics." <>
Subject: Re: [TowerTalk] Homebrew Crank-up
From: jimlux <>
Reply-to: "Tower and HF antenna construction topics." <>
Date: Sat, 27 Mar 2010 16:34:53 -0700
List-post: <">>
Stan Stockton wrote:
> 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

So the inside "diameter" of the lower section is about 27-30 inches? 
That's quite a bit larger than the outside dimensions of the 55G or 65G.

You'll need to fabricate some sort of traveler that would hold the 
"bottom" of your upper stick.  Having a lot of clearance does mean that 
"binding" might be less of a problem.

I'd think about something that is a few feet tall with rollers at the 
top and bottom. That way it would stay properly oriented laterally. 
maybe roller pairs at an angle, to provide torsional stability of the 

Something similar at the top of the lower stick to serve as guides for 
the upper stick as it emerges. Here, I'm thinking 3 pairs of rollers (a 
pair at each corner).

You need to do a little calculation and see how much bending moment 
there is on the upper stick, so you know what the lateral force on those 
rollers is going to be.

You might be able to not use rollers at all on the top.. just have a 
metal sliding on metal sort of thing, although I'd worry about wearing 
off the galvanizing.

You're defininately going to have to be able to climb the outside of the 
outer section, because whatever is at the top is going to need 
maintenance (e.g. greasing of the bearings)

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