Saturday, May 16, 2009

The R8 has cleared the tower...

...and now stands proudly at a height of about 12 metres at the top of its tower and mast.

Thanks to a posse of 9, mostly from the North Shore Amateur Radio Club, we were able to get the 21 metre long hunk of metal, consisting of triangular tower plus mast, plus R8, from the horizontal to the vertical. Thanks guys!

I would especially like to thank John White VA7JW, who's expertise in matters radio, and indeed the practicum of raising antenna towers, has been invaluable. John arranged the day, rounded up the help, provided invaluable advice and tips, and directed the actual lifting. As a brand new member to the club I've been truly impressed by the generous welcome back to the hobby.

The main concerns in relation to this particular antenna raising project, were the relative proximity of various power and communications lines. The tower is installed at the back of the property, and the while this is a very convenient location, it is nevertheless also close to where the service lines arrive into the property from an easement directly behind the QTH. A simple rotation of the antenna with the tower base at its footing would not have allowed the top of the R8 to clear coaxial lines for cable TV/internet. Additionally, it was essential that the tower not over-rotate, or swing away from the house, lest it become entangled with the service cables to the house.

In practice, the common method of lifting from the middle of the tower and then walking the base in toward its footing served well. A pulley arrangement relatively high in the eaves, hung from threaded eye bolts into the wall worked effectively, though the weight of the tower required 3 men on this lifting rope, and eventually also an improvised rope anchor (the kids' wooden climbing frame!). With the assistance of the anchor, the lifting rope could be locked while the base was lifted and walked in, which otherwise put considerable extra dynamic strain on those manning this rope. Besides the lifting rope, other ropes were utilised to pull the tower out from the eaves (important to avoid it touching the roof/shingles prior to landing on its standoff bracket as it reached the vertical).

With the tower up and raising team left to enjoy the rest of their Victoria Day long weekend, the next task was to create an cable entry point through the wall of the 'shack'. Then came time to finish running the feed line down the tower and in through the wall, and finally the fitting of the PL-259 plug ready for connection to a radio.

As a Brit, I'm still not completely used to the method of house construction here - but it certainly has its benefits when all you have to do is take a bore to your wall, then fit a length of PVC pipe through the hole to establish a little tunnel for coax. The biggest challenge of this task was planning the location of the hole!

So, at this point, I now have an installed R8 with a completed feed line, ready for testing. I still have a number of 'completion' tasks to undertake on the tower (install an extra wall bracket) and at the coax ingress point (exterior weather proofing and a temporary fill in the tunnel to keep out the weather/bugs). However, now at last the actual radio fun can begin!

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