Actually, if the tower is designed to be self-supporting, anchoring it anywhere could compromise the structural integrity. It's designed to give some across the entire structure, and if you tie one point to a fixed point, it will flex more at that point and eventually could fail there - much like flexing a piece of wire in one point too much.
Joe M. Jack Taylor wrote: > > Depending upon the wind loading on the tower, I would be cautious about > fastening *anything* to the fascia board of a modern day house! If your > tower > is self supporting, design the base to handle the load. Don't rely on the > house > else over time you may end up with cracks in the interior walls. If the > tower > is to by guyed, don't use the house for an anchor :-) > > But on the otherhand if it is a short tower with little wind load, have at > it! > > Jack - N7OO > > ----- Original Message ----- > From: Eric Lemmon > To: [email protected] > Sent: Sunday, July 29, 2007 6:36 PM > Subject: RE: [Repeater-Builder] Rohn 25g Tower > > Don, > > As others have mentioned, it is best to first attach the house bracket to > the house, and then install the tower. > > I did exactly that at my house, with a 25G tower comprising two 10-foot > sections and a 5-foot embedment section. Once I knew roughly where the > tower would be, I put a 50-inch section of heavy aluminum channel behind the > fascia board, and lag-bolted it to each of four roof trusses. I then > drilled through the fascia board and the aluminum channel for several > 3/8-inch stainless steel bolts to hold the house bracket solidly to the > fascia board. Then I set a tower section in place to see where the hole > needed to be, with the section perfectly plumb. Once the hole was dug per > Rohn's foundation drawing, I added the rebar and set the embedment section > in place with one tower section clamped into the house bracket. After > triple-checking that the tower was plumb, I poured the concrete. Although I > bought an electric concrete mixer from Harbor Freight just for this job, > after going through 26 ninety-pound bags of ready-mix concrete, I was > pooped! If I ever do this again, I am gonna hire a ready-mix truck and a > concrete pumper to do the work. > > 73, Eric Lemmon WB6FLY > > -----Original Message----- > From: [email protected] > [mailto:[EMAIL PROTECTED] On Behalf Of Don KA9QJG > Sent: Sunday, July 29, 2007 3:26 PM > To: [email protected] > Subject: [Repeater-Builder] Rohn 25g Tower > > On a Rohn 25g Tower that will be put on the Side of the House can anyone > Tell Me if the Rohn House Bracket Has to be Mounted First, or can the Tower > Be put up First. > > Thanks Don > > KA9QJG > > > Yahoo! Groups Links > > >
