[TowerTalk] Dipole Ends

[Larrie Sutliff]

Tim,

Hook-eyes screwed into the trunks of trees holding non-corroding (marine)
pulleys threaded with dark Dacron-covered (uV resistant) support line have
worked well for me.  I use 5/16 or 3/8 x 6" hook-end lags (drill the tree to
ease installation), leaving a couple of inches protruding from the tree to
allow for trunk growth.  Just bend the open hook closed after the pulley is
attached.  If the trees don't swing much in the wind, adequate slack in the
line may be sufficient to accommodate movement.  If the trees move a lot at
the pulley attachment point in a heavy wind, an appropriate spring lash-up
at the line tie-down locations may be helpful.  At the tower center point,
consider an attachment that allows the dipole to swing some as the trees
move rather than a hard attach (e.g., a few feet of support line between the
tower and antenna feed point).  Tower attachment can be accomplished by
feeding the center support line through a pulley on the tower, a feature
that allows easy adjustment of slack as well as a way to lower the antenna
for maintenance from the ground.

Larrie
W2UL

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Tim N9PUZ
Sent: Friday, August 29, 2008 3:59 PM
To: towertalk at contesting.com
Subject: [TowerTalk] Dipole Ends

I'm going to hang the center of a dipole from my tower. The question 
is really about attaching the two ends of the support ropes running 
through a pulley and down to provide for some movement in the wind.

Our yard has several trees which are good candidates. For a more 
permanent installation like this (vs a Field Day type setup) what is a 
good technique for attaching to the tree trunk? Screw eye into the 
trunk itself? Some sort of belt type affair around the trunk?

Thanks,

Tim, N9PUZ
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