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How to Assemble a Cushcraft Amateur Radio Antenna 15-3CD

The Cushcraft 15-3CD is a 15-meter, three-element beam antenna intended for use by amateur radio enthusiasts. The device consists of three sets of aluminum tubes bolted onto a central boom in a perpendicular configuration. Once assembled, the user then mounts the antenna onto a previously-installed vertical mast. A special element, called the Reddi-Match, is affixed to the underside of the device; this component allows the user to adjust the antenna's tuning as necessary. Basic hand tools will suffice for the assembly process, and all of the required fasteners come packaged with the antenna.

Things You'll Need

Phillips screwdriver
Socket wrench

Instructions

- 1
  Assemble the boom, which consists of two tubes, labeled BB, joined to a single, shorter tube, labeled BA. Slide a worm clamp over each end of the BA tube, then insert the tapered ends of the "BB" tubes into the openings at the ends of the BA tube.
- 2
  Insert two of the packaged machine screws into the holes near the ends of the BA tube. Use the Phillips screwdriver to tighten the screws and the worm clamp. Complete the boom assembly by fitting plastic caps over the remaining ends of the BB tubes.
- 3
  Assemble the reflector. This component consists of one EA tube, two EB tubes, two EC tubes and two ED tubes; the EB tubes are designed to join to the EA tube, the EC tubes to the EB tubes and the ED tubes to the EC tubes. Use worm clamps at the ends of the EA, EB and EC tubes to secure the pieces together. Fit plastic caps to the ends of the "ED" tubes.
- 4
  Assemble the driven element. Use worm clamps to join one EA tube, two EB tubes, two EC and two EE tubes together. Before joining the second EB tube to the EA tube, fit the small Reddi-Match clamp over the end of the EA tube and the large Reddi-Match clamp over the larger end of the EB tube. Fit plastic caps to the ends of the EE tubes.
- 5
  Assemble the first director element. Use worm clamps to join one EA tube, two EB tubes, two EC tubes and two EF tubes together. Fit plastic clamps to the ends of the EF tubes.
- 6
  Position the reflector over a point located 2 inches from one end of the boom. Place a U-bolt bracket over the mounting point, then align the holes in the middle of the reflector over the holes in the bracket. Insert the ends of the U-bolt through the bracket and reflector. Slide a backing plate over the ends of the bolt, then use washers and nuts to fasten the U-bolt, securing the reflector to the boom.
- 7
  Position the driven element over the center of the boom; the distance between the ends of the driven element and the ends of the reflector should measure 81 inches. Use a U-bolt to secure the driven element to the boom as you did with the reflector, substituting the Reddi-Match connector bracket for the backing plate.
- 8
  Use a machine screw, washer and hex nut to secure the insulator to the bottom of the small Reddi-Match clamp. Attach the 3/8-inch clamp to the remaining end of the insulator in a similar manner. Slide the Reddi-Match through the opening at the end large Reddi-Match clamp.
- 9
  Feed the Reddi-Match through the 3/8-inch clamp, into the Reddi-Match connector bracket. Use machine screws, washers and hex nuts to secure the Reddi-Match to the connector bracket and large Reddi-Matc clamp.
- 10
  Use a U-bolt to secure the first director element to the remaining end of the boom. The distance between the ends of the first director element and the ends of the driven element should measure 81 inches.
- 11
  Use two U-bolts, two aluminum V-blocks, four washers and two hex nuts to secure the mounting plate to the mast. Use an equal number of U-bolts, V-blocks, washers and hex nuts to secure the boom to the mounting plate.

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