In my case the eaves are 12" plus I wanted a bit of extra clearance to be
able to climb in/out the attic window. The only reason for this project is
so that I can locate the 432 MHz thru 10 GHz gear in the attic or on the
tower and minimize feedline loss to 50-60' of 7/8" Andrew.
The Rohn HBUTVRO design is a whole lot stiffer than their smaller brackets.
They will be mounted to the cedar siding with 2x8's and secured with thru
bolts to another 2x8 back support against the 2x6 wall. Two small lag bolts
will be used only for positioning the outside 2x8 and not for support
Its not going anywhere, even with 2 small microwave dishes on sidearm
rotators.
Carl
KM1H
----- Original Message -----
From: "Jim Jarvis" <jimjarvis@optonline.net>
To: <towertalk@contesting.com>
Sent: Friday, August 17, 2007 7:35 AM
Subject: Re: [TowerTalk] house bracket rust stains
>
> TT:
>
> The idea of using non-galvanized metal as a bracket system
> isn't very appealing. Wood can be painted to match the house,
> and spreads the loads to prevent siding damage.
>
> I have routinely made my house brackets from treated lumber,
> and not used the Rohn bracket. Three reasons: The Rohn is
> too flexible. The Rohn stands out from the house too far.
> The Rohn doesn't spread the load across the structure enough.
>
> None of my applications have had a deep-eave to clear; at worst,
> just a 4" gutter plus facia. If I had an 18" eave...I'd build a
> rohn bracket into my wood system.
>
> I've used 2x8's, spread over 4' of siding, lag screwed into
> the joists. If I need more standoff, I double the 2x8
> and use longer lags. On each side, I add a piece of 2x6, which is
> held by carriage bolts coming from the backside of the 2x8 tie.
> Those bolts are long enough to also hold a 2x6, which passes
> through the tower, to hold it in place.
>
> So, side loads are captured by the 2x6's and transferred into
> sheer loads on the carriage bolts. Pullout loads are captured
> by a 2x6 in sheer, and transferred to tensile loads on the
> carriage bolts and lags. Nice and solid. I've used it for 25g, 45g to
> 50',
> and MA-40's.
>
> A brief word on the fasteners: The lags are usually 1/2"x12".
> YOU MUST DRILL PILOT HOLES. For a 4' tie-beam, I use six of these,
> 2 each in each of the 3 intersected joists. The Carriage bolts are
> 1/2", and have to pass through a sandwich of 3 or more 2x8's or 6's.
> At 1.75 each, that's a minimum of 5.25". So 6" bolts are the minimum.
> Use large flat washers with all bolts. Excess length is not a virtue;
> you will bash knuckles.
>
> This system requires some planning, and determining position of internal
> wall, roof and floor truss structures, before tieing into them. If you
> can thru-bolt with a back plate, rather than use lags, it's obviously
> better, and easier.
>
> Removal has proven zero damage to the siding, with three installs,
> apart from the lag screw holes, which are easily filled and painted.
>
> N2EA
>
> Jim Jarvis, President
> The Morse Group, LLC
> 732 548 5573 office
> www.themorsegroup.net
> results@themorsegroup.net
>
> Strategic Planning and Success Strategies
> for Sales Professionals and Entrepreneurs.
>
> Sales Excellence Series beginning September 19, 2007
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|