[TowerTalk] Mast Binding in Rohn 25 Pointy-Top

[Steve Jones]

Jim-

Here are a couple of pictures of how I installed my mast through a Rohn 25
pointy top sleeve.  The rubber pipe adapters for cast iron/plastic pipe are 
available at any Home Depot.  I
had to use a rat tail file to grind down the threads on the 1 1/2" side of
the fitting, which is slightly less than 2" ID from the factory.  I coated 
the upper part of the mast
with white lithium grease before I slid it up through the pointy top sleeve, 
then
slid the rubber adapter down from the top and secured it with the clamp so 
the lower part covered the opening of the tower sleeve.  Never had a
binding problem in the 10years it was on top of my 100' Doug fir, before the
tree died.

BTW if it binds only when it rains, it does sound like redwood debris that 
would swell up when wet.  That duff gets into everything around here!

73,
Steve
N6SJ

----- Original Message ----- 
From: "Jim Brown" <jim at audiosystemsgroup.com>
To: <towertalk at contesting.com>
Sent: Saturday, November 12, 2011 12:40 PM
Subject: [TowerTalk] Mast Binding in Rohn 25 Pointy-Top


> Crew,
>
> My Rohn 25 tower holds a 3-el SteppIR up about 125 ft in redwoods, about
> 50 ft below the tops of the surrounding trees.  For at least 6 months,
> the mast has been binding when it's been raining much.  I've carefully
> studied things from the ground below, and there's nothing hitting the
> antenna, so I believe it must be binding in the pointy-top. K6XX and  I
> have banged ideas around, and all we can come up with s debris from the
> trees above collecting in the space between the mast and the sleeve, and
> expanding as it gets wet.
>
> As a solution, we're thinking about hitting that gap from above with a
> couple of cans of WD40, and perhaps adding some sort of rubber gasket on
> the mast just above that point to prevent additional debris collecting
> there.
>
> Does this make sense?  Any experience from others on symptoms like
> this?  Any other suggested solutions?
>
> 73, Jim K9YC
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