[TowerTalk] Rohn 25G: hinged base plate vs not?

[David Giuliani]

This is for a 40' 25G tower, roof mounted, using a Hazer to support SteppIR
antenna.

Hinged plate would make it easier to erect, but is it reliable over the long
haul?  
Is it sturdy enough to support the structure with 2 guys detached, as is
recommended to lower/raise the hazer?

David, WA6PXX

>  -----Original Message-----
> From: 	David Giuliani [mailto:David at Giuliani.org] 
> Sent:	Tuesday, November 04, 2003 12:20 AM
> To:	Towertalk
> Subject:	Hardware for roof antenna...
> 
> 
> I'm building a new house and want to prepare it for mounting a roof
> antenna "support structure"  to the garage.  I'd love to get any and all
> advice re completing framing and roofing, for later tower installation.  
> 
> Current antenna plans:  
>      80 mph wind zone, never much ice
>      40' Rohn 25G tower mounted on peak of roof (at 28' elevation).
> 	(<-- is this still a good choice despite Rohn being in financial
> difficulty?  Alternative manufacturer?)
>      10 sf antenna max (e.g. SteppIR, 2 meter beam, 144/440 vertical)
>      Hazer system (e.g. Glen Martin)
>      1 or 2 guy wire sets at 120 degrees
>      lower end of guy wires attached to corner framing of house, 25' from
> base
>      radio room immediately below antenna, 1 story down  
> 
> Attachment to house
>      guy wires: 
>           anchors rated at 5,000 #, mounted to roof truss (designed for
> attaching climbing equipment) but terminating with a nice "Eye"
>                (<-- better idea?)
>           lots of metal tie bars holding wood members together and down to
> foundation
>      base: 
>           vertically placed glue lam penetrating through roof peak, bottom
> well tied to central bearing post.
>           BP25G base plate, bolted to lam (<-- better idea?)
> 
> Conduit: 3" PVC with service head (<-- suggestions?)
> 
> Grounding:  (<-- haven't finished designing this part yet; ideas?)
>           #2 copper stranded wire running through bldg to 10' ground rod
> sunk in ground
>                 clearance between ground rod and concrete floor
>           2-4 copper straps running down roof and along outside of bldg to
> ground rods, 2 rods per run
> 
> Anything else to consider?  
> 
> David Giuliani, WA6PXX
> Mercer Island, Washington
>