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.P1020752.JPG
Although not called for in the assembly manual, on recommendation from Brian W7BJN, a glue bead is placed at each nesting tube junction to prevent them from sliding back in over time. Constant movement in the wind at the top of a tower can cause them to work in according to Brian. Made sense to this crew.
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OK, how to these hollow fiberglass tubes go together??
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Time to pour concrete. The concrete truck can only reach one guy station, so a motorized wheel barrel is used to transport 8 yards of concrete into the main tower and guy station holes.
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One of three ground tower ground rods. The are each connected to a tower leg with both a #4 solid copper wire (per NEC) PLUS a 1 1/2 inch low RF impedance copper strap. Once connections are made, the ground rod is then driven down so it is at least 6 inches below grade.
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Coax switching unit. All three active elements may be driven.
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Left To right: Gary W7TYQ (Yreka CA), Dave W7DJE (Florence, OR) and Steve WA7DUH install the rollers on the hazer. Gary and Dave drove up to help Steve & Linda put this antenna up on the tower.
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Installing the driven element return fixture.
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Driving those ground rods down at least 6 inches below grade with a power hammer.
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Yea-- this is the way to handle concrete.
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A very thick polifin heat shrink tube locks each joint into place.
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Guys from Speedy Angeles Concrete, LLC out of Pasco WA do the work. They have the equipment and muscle, and did the job for a good price.
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Each of the 3 tower grounds are out abot 7 feet from each tower leg, with #4 solid copper and 1 1/2 inch copper strap back to the tower, over to the house electrical ground and down to the ham shack. Two inch rigid non-metal conduit is also buried in the trench to hold 4 runs of LMR-400 coax.
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WB7CNV (Linda) bows properly to the tower gods.
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Fritz loves to ride in the cart as Steve (WA7DUH) goes to the shop to pick up SteppIR antenna parts.
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Guy lines are Phillystran, a non-conductive arimid fiber. Cable grips are used for termination.
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Here is the house ground rod as we found it. It doesn't meet code. Only one ground was found or wired into the electrical panel, but code requires two, with at least 6ft separating them. The solid copper wire is also too small, and the one rod was not 6 inches below grade. So we fixed that up.
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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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Control lines from each active element and the coax switching relays come together into junction terminals.
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Assembling an element housing unit (EHU) prior to installation.
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The reflector EHU and element return fixture mounted on boom.
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Drilling through mast for 3/8" bolt anti-rotation (no-slip).
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Gary (W7TYQ) Dave (W7DJE) and Peter (AC7SB) attach the reflector Return Element Support to the boom.
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There is a lot of electronics and relays that go into this antenna. Pictured is Gary W7TYQ that came up to help from Yreka CA.
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Dave W7DJE looks through the boxes for parts. Duffy helps.