Sunday, April 26, 2009

Cushcraft R8 assembled (minus radials)

R8 construction was essentially completed today. The radials have been left off for convenience until the final assembly of the tower stack (tower + mast + antenna).

The R8 is a beast when fully assembled - a 9m long droopy ungainly thing when laid out horizontally - a bit like a fish out of water. No doubt it will translate into a being a more majestic looking thing when lofted into the vertical :-)

The assembly went pretty well. The instruction manual organises the assembly process into logical phases/sections. There were a couple of errors in the manual, but nothing serious. These were:

  • An incorrect length given for one of the main radiating elements. It's fairly obvious which element is required though, from its diameter, drilled holes and slotted ends.
  • One jubilee clip is unmentioned in the latter stages of construction, appearing in neither the instructions nor the bill of materials for the step. It does however appear in the requisite diagram (and it's pretty obvious that its required to attach an assembly).

Next steps are to prepare one end of the feedline (LMR-400) and get this connected to the feedpoint on the R8 matching network box. The R8 comes with a small supply of silicone gel to inject into a little plastic boot that covers the connecting PL-259 in order to keep moisture out of the top of the coax.

The tower can also be assembled now (bolted together) in more or less the location for raising it. The mast can be installed in the top section with about 3 foot or more above the top of the tower to achieve the > 8ft above the root apex for an optimum radiation pattern. When the R8 is eventually attached to this, the coax can be strapped with nylon ties down the mast and tower to a level suitable for feeding in under the eaves.

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