Albums: WA7DUH And WB7CNV Tower Construction
WA7DUH And WB7CNV Tower Construction
Photo essay of tower project at the station of Linda WB7CNV and Steve WA7DUH. They live just outside of the Richland and West Richland city limits in Benton County. Project is to initially erect a 65 ft guyed tower, but to design it for 75 ft or higher. Benton County has an ordinance controlling "communications facilities" (BCC 11.65) which includes "communication towers and antennas." Many of the requirements are exempted for amateur radio towers and antennas not exceeding 65 ft.P1020717.JPG
Assembling an element housing unit (EHU) prior to installation.
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Dave W7DJE looks through the boxes for parts. Duffy helps.
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Assembling an inner guide and support tube that is slid into the large end of the element tubes to provide a consistent diameter for the beryllium tape that must slide in and out.
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Boom joiner on the SteppIR Dream Beam DB18E). Colored dots on the pieces helps the assembler to find and line up the proper pieces.
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After assembling 1 of the active elements on the grass by the tower in about 3 hours, assembly was moved into Steve & Linda's shop where an assembly line could be set up, as there are 6 of these to make. Time was reduced to about 1 hour per unit.
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One of three rebar cages for guy stations. Each guy station consists of a reinforced block of concrete 6ft x 4ft x 2ft high buried 4 ft below grade. That long 3/4 in rod is what the guy lines are tied to, and is buried in the concrete block. Each rod will sustain at least 8000 lbs of pull, which is about 4X overkill, since the worst case forces with an 88 mph wind is calculated to be 1000 lbs. Building code in Benton Co. requires survival of 88 mph winds.
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Trenching between the tower base and the ham shack entrance. The picture doesn't really show the 18% downslope here, and the trencher was stuck and rolling into one of the deck support posts. Come-alongs are keeping the trencher from taking out the deck post plus the tractor is extracting.
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The interior of a SteppIR Element Housing Unit (EHU) with stepper motor that drives copper-beryllium tapes in and out of the hollow antenna element tubes. The tapes are the radiating/active elements of the Yagi beam antenna. This SteppIR antenna is able to be resonant anywhere between 6.5 Mhz and 54 Mhz by adjusting the lengths of the Beryllium tapes. The tapes are wound on the spools that are seen in the picture using the cogged wheel that engage holes punched into the tapes. Cogged wheel is driven by a stepper motor, which has absolute positioning capability. The computerized controller knows how far to position out the tapes in the driver, reflector and director tubes for any given frequency.
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Guy lines are Phillystran, a non-conductive arimid fiber. Cable grips are used for termination.
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All the cabling prior to clean up.
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This cart has a dump function, which really helps unloading!
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Peter Rosenberg (AC7SB) from Fall City WA joins the antenna assembly team. Steve (WA7DUH), Peter and Gary (W7TYQ) apply anti-sieze compound to the staddles that will be used for one of the Return Element fixtures. Liberal use of anti-sieze compound is critical because of the many dissimilar metals used in both the antenna and hazer (aluminum, stainless steel hardware and galvanized steel.)
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Drilling through mast for 3/8" bolt anti-rotation (no-slip).