[TowerTalk] Bracketed, guyed towers
Bud Hippisley
k2kir@telenet.net
Sun, 09 Sep 2001 15:18:21 -0400
Does anyone here have any experience with or opinions about replacing the first set of guy wires on a (say) 90-foot Rohn 45 tower with a house bracket? (In other words, a 90-foot tower bracketed to a house at 30 feet, with steel/insulator guy sets at 60, and 90 feet.) The tower would have a "normal" 3 x 3 x 4 concrete base and a second house bracket about six feet above the base. Tower top load would be a mid-size tri-bander at 96 feet, a Cushcraft 2-element 40 at 91 feet, a 2-inch OD ten foot mast stuck 3 feet into the tower, and a T2X rotor. One or two small fixed mounted tribanders might be attached somewhere between 30 and 60 feet up.
Topics I am looking for feedback on include:
1. Lightning (and grounding) issues, as compared to a similar but hypothetical 90-foot guyed tower located perhaps 25-30 feet from the house.
2. Near field issues, as compared to the same hypothetical 90-foot guyed tower, still located 25-30 feet from the house, if the tower is shunt fed on 80 and 160 meters. (The house bracket would be on one wall of the first floor radio shack.)
3. Sound transmission, as compared to a 50-foot house-bracketed tower. (Chosen because I *know* what a 50-foot bracketed tower sounds like.)
4. Are the forces on the house bracket greater or less because of the extra height and the added guy stations, relative to a 50-foot house-bracketed tower.
5. Any other important considerations I may have overlooked.
To answer the first obvious question that will come up, I can't use guys at 30 feet because one of them would cross my driveway at too low a height for adequate vehicle clearance and another would pass in front of a large living room window.
TIA --
Bud, K2KIR
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