Cutting those areas will reduce the strength. The weight should not be much
of a factor once it's mounted. The swing arm mount adds a lot more stress
to the tree and if that is the concern, I would omit it and have less beam
rotation.
John KK9A
To: towertalk@contesting.com
Subject: Re: [TowerTalk] HF yagi - tree mount fixture - photos: Need
suggestions
From: Date: Sun, 27 Sep 2009 14:24:00 -0400
Sorry, the rotor/bearing mount plate actually weights about 62lbs and not
84lbs as per the original post.
My Poor metric -> pound conversion after weighing it with a spring balance
marked in kilos.
On Sun, Sep 27, 2009 at 2:15 PM, wland wland <wlanddx@gmail.com> wrote:
> Hi all,
> Here is the contraption i have got a steel shop to fab.
> http://picasaweb.google.com/wlanddx/TreeMountFixture?feat=directlink
>
> Question:
> In one of the photos, i have marked cutting points in red color. Should
> i
> cut or not?
> The objective is to reduce weight. Cutting the gussets will reduce the
> weight by at least
> 14lbs. Don't know about the gain in weight by cutting a section of the
> round tube for the swing gate.
>
> I plan to mount a TA-33 or A3S.
>
> I am getting ready to galvanize this contraption and will need to make a
> decision (cut or no cut?) in
> the next few days.
>
> Here are the details.
> 1. Swing arm - 1/8" thick steel and weighs about 22 lbs.
> 2. The rotor/bearing mount - 3/8" thick steel and weights about 84 lbs.
> 3. In addition, gotta add the weight of the rotor (say 20lbs ??) + HF yagi
> (30lbs max)
>
> Since this will be up on a tree and will be secured using
> a) Multiple lag bolts (2 to 6 perhaps).
> b) There are 2 nuts welded at the top and bottom of the fixture. An EHS
> steel cable
> that is used to guy towers will be run around through a couple of 2x4
> piece of wood
> with holes drilled in it for use as spacers. Then a turnbuckle will be
> used to tighten it.
> The turnbuckle will be adjusted yearly to let the tree grow around.
> c) In addition, 2 eye bolts will be installed, one above the fixture on
> the
> opposite side of the
> bracket, a few feet above and below it. A safety steel cable will be
> strung through the eye bolts. This will
> act as backup in case the tree breaks off at the top or the primary
> cables gives away.
> At any rate, i don't want this to come down. If it were to, its gotta
> come down when the tree
> comes down. In all, there will be 4 cables around the tree to secure it.
> d) Annual inspection by a tree climber.
> e) This goes in between the branches of a tall pine at the 50ft level. At
> the
> mount point, the trunk is about 1.5 to 2 ft wide. This is a type of
> pine tree that cannot be topped.
>
> All painted with camo paint to blend in.
>
> Any comments? suggestions?
>
> 73s
> <name/callsign withheld to avoid detection by neighborhood busybody
> googlers>
>
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