[TowerTalk] HF yagi - tree mount fixture - photos: Need suggestions

[N4NW]

I am not an engineer but I recently visited a Holiday Inn but seems 
to me that removing the areas in the photo in red is going to 
significantly weaken the device.

73's
Tom

At 02:15 PM 9/27/2009, you 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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Tom Gregory,  N4NW
n4nw at n4nw.org

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