Re: Antennas and Launching

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From: Bill Howell (bhowell@mail.utexas.edu)
Date: Wed Mar 13 1996 - 20:05:57 EST


>Does anyone have any experience with Antennas West's Quick Launch system?
>If so, how does it work and how well does it work? I'm looking for
>something to help me get an antenna up when camping.

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I haven't tried their Quick Launch system. But...they do have some great
double-dacron rope..I just ordered abt 800 ft of it so I wouldn't run out
for awhile :^)
It's slick enough to slide over tree branches easily. Knots made in this
stuff can be untied, even after many moons (I just untied/retied my 10m
dipole last night, standing on the garage roof _in the dark_). Nice rope.
(is 10 open yet?)

What I use for launching is a roll of thin nylon line (5 bux/thousand ft at
a recent hamfest), and a Master combination lock.

Everyone has one of these locks (you know...the one you've forgotten the
combination to),in a bottom drawer somewhere.

The lock has just the right 'heft' for chunking over trees, up to 30 ft or so.
They also have a handy loop at the top, to tie your nylon cord to.
I've found that _cotton_ string tends to stick/drag when passing over limbs.
This is not what you want to happen.

Lay out enough line on the ground to make it over the tree and down the
other side.
Try to spread out the line on the ground so that when you launch, the
loops of line don't catch on each other and you end up launching a big
wad of knots.

Also, don't lay your line out over any twigs, etc. Murphy's Law states that
the line WILL pick up the twigs at the moment of launch, increasing the drag
and reducing your throw distance.

If this is a temporary installation, just use the twine to support the
antenna. If it's to be 'permanent', tie the twine to your 'good' rope
(using plastic electrical tape, 'barber-poled' over the knot- this will
keep the knot from hanging up on limbs) and pull it through the tree.

                  <jump to related topic>

For years I have used screen-door springs on one end of my skywires,
to keep the swaying trees from streching them.
The springs get rusty after awhile, and I started thinking about all
those layers of rust being rubbed together between the spring coils,
along with all the RF floating around that area (maybe this matters, maybe
it doesn't) anyway.....

I tried using bungie cord material this time. I'm talkin' about the large stuff
here. Found it at Builders Square. 1/2 inch diameter. 50 cents/foot.
So I bought three feet, plus a pack of end-hooks for 70 cents.
Put it all together in a couple of minutes. Really hefty.
This ain't no down-stream bungie cord! I installed it on the aforementioned
10m dipole.

Time will tell how it holds up to the UV from 'ol Sol.

Thanks for the BW.

 
Bill Howell
University of Texas at Austin
Performing Arts Center
Electronic Maintenance
voice: (512) 471-1388
fax: (512) 471-3636
bhowell@mail.utexas.edu

N5ALO QRP-L #415

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---Then bring us a shrubbery. Nee.

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