[TowerTalk] Inverted L questions

[Jim Lux]

At 03:22 PM 8/24/2006, Peter Dougherty wrote:
>At 05:57 PM 08/24/2006, Nick Pair wrote:
> >I have one suggestion. Use a continuous loop of UV resistant rope
> >through the pulley. With a pulley at ground level you can use the
> >loop splice point to attach your L or whatever you choose, This way
> >if wire breaks you will have a haul down rope all ready to pull the
> >antenna attachment point back down. Also you can put whatever you
> >choose at ground to take up the tree sway and keep tension on the loop.
> >You didn't mention where the end of the horizontal wire is anchored.
> >This also needs sway protection and might end up a similar
> >arrangement as the main support.
>
>Looks like the loop idea is the winner. As I mentioned off-list to
>another kind soul who replied, I'm an ex-apartment dweller (small
>city apartments all my adult life) and thus never needed to know
>about such things. I'm trying to visualize how to do this. Any online
>drawings/photos, etc?


Heh... after you don't have a loop, and it breaks, and the end of the rope 
runs all the way up to the pulley and jams, you'll be a believer.  Some 
folks at the JPLARC/CITARC (W6VIO/W6UE) field day this year found that out.

If you need an example, take a look at a flagpole.  Imagine your antenna 
wire connected to one of the clips that hook to the flag.


>Also, wouldn't a loop of rope get caught up in all the branches
>sticking out of the tree, making it very difficult to raise or lower
>the insulator and the wire it supports?

yes and no.. you've got the haul line coming down anyway, so having a 
second parallel strand doesn't make much difference.  And yes, that's part 
of the challenge with using a tree for a support.. allthose darn 
branches.  Some trees are better than others (conifers make it easy! 
California Live Oaks with multiple trunks make it hard).  If your tree has 
multiple trunks at the top, hanging your pulley from a steel cable between 
the trunks might make life easier, since you can get a straighter run to 
the ground for the haul line.


>As for the far end of the horizontal wire, after the end insulator it
>will connect to 3/16" dacron rope, over a marine pulley in a distant
>tree, and to a weight of some sort (yet to be figured out) to keep
>the whole shee-bang taught.

A cloth (or pseudo cloth) bag full of sand or dirt makes a nice weight. 
Dumbbells (cheap at the local sporting goods, exercise equipment store) are 
easy to tie a rope around and the rope doesn't slide off the end. Part of 
it depends on how much it's going to move as the tree/wire moves in the 
wind, and what it's going to rub against.  As long as the rope is a 
continuous loop, if the weight falls off, you just haul the wire back up 
and hook a new weight on.

Or, if you want really high tech and something to freak the folks out 
with... get one of those depleted uranium counterweights that are clad in 
stainless steel.  remarkably dense.




>Cheers,
>
>Peter,
>W2IRT
>
>
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