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From: "Mac English" <km9zkb9mdl@yahoo.com>
Sent: Saturday, August 28, 2010 12:10 PM
To: <towertalk@contesting.com>
Subject: [TowerTalk] Guy wire height from anchor to tower
> I would greatly appreciate it if someone could help me figure
> out how to
> calculate guy wire height from the guy anchor up towards the
> tower.
>
>
> My tower height will be at 70 ft. My first set of guy will be
> at the 32 ft level
> the second set will be around the 68 ft level. The total
> distance to each
> anchor from the base of the tower is 45ft.
>
> On one of my anchors is only 14 feet away from my home. The max
> height on my
> home where the first set of guys will pass is around 11 feet
> high. I need to
> know how high that first set of guys will be at 14 feet from
> the anchor to the
> roof where these guys will pass. The length of the guy wire on
> the first level
> of guys is 53 feet long from anchor to tower. All anchors will
> be about 1ft 8in
> above ground.
>
> I am wondering if the first set of guys will be high enough off
> the ground to
> clear my home. I have some logistical issues with respect to
> where I can place
> the tower & guys on my property because of utilities and the
> placement of
> buildings on my property.
>
For a horizontal distance of 45 feet, the guy wire will rise
30.34' (32 - 1.66)
So for every foot of horizontal distance, the wire will rise
0.674' (30.34/45)
For a horizontal distance of 14 ft, the guy will rise 9.436'
(.674 x 14)
Since the guy started at a height of 1.66', it will be at a
height of 11.096' (9.436 + 1.66) (ignoring sag) above ground when
it passes the
top of your house. That's too close. You could make the anchor
higher, guy higher on the tower, guy further out, or put the
anchor for the lower guy on the other side of the house, if
any of that is possible.
> Plus while we are at it I will be digging a 2x2x4 ft hole for
> the base of the
> tower. The anchors will be 5ft deep by a 2 ft wide undisturbed
> hole. I need to
> figure out how much concrete will go in each hole and how much
> concrete will it
> take to fill the tower base.
You should have about 2" of concrete above grade for the tower
base.
2 x 2 x 4.166 = 16.664 cu ft = 0.62 cu yd
I guess you are using raised anchors, so the concrete should be
2" above grade here also. I think you meant a 2x2x5' square hole.
2 x 2 x 5.166 = 20.664 cu ft = 0.765 cu yd
If you meant a 2' diameter round hole 5' deep, it would be
3.1416 x 5.166 = 16.23 cu ft = 0.6 cu yd
Dave Hachadorian, K6LL
Big Bear Lake, CA
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