Antenna preparations for ARRL Field Day

Friday, June 20th, 2008

It’s been awhile since I’ve discussed non-computer-related construction projects on this blog, so to break the drought, here are some details on a shortly upcoming antenna project.

The Amateur Radio Relay League’s annual Field Day is coming up next weekend. Field Day is the largest weekend of the year for amateur radio operators. It includes of all sorts of outreach activities, as well as heavy contesting (racing to see who can make the most radio contacts over the weekend). Since I only became involved with amateur radio recently, it’ll be my first Field Day. Unfortunately, the only antenna I’m operational on right now is a 44″ magnetic mount 70cm/2m dual-band whip antenna. It’s decent for operating mobile, but its performance isn’t anything to write home about.

Luckily, I bought a 17-foot 70m/2m dual-band base station antenna at a hamfest in March. A 201.5″ antenna is a bit more impressive than a 44″ antenna, don’t you think? I haven’t actually gotten around to installing the antenna yet, but Field Day is as good a reason as any to finally get it done. I’ve already done all the prep work and assembled the mount, which you can see in the picture. The domestic house cat is for scale.

I bought all the parts from Home Depot at not-too-ridiculous prices. All of it is galvanized steel (and thus rustproof), except for the tee-junction, which this particular Home Depot seemed to be out of in galvi. I do have a can of clear gloss waterproofing spray paint laying around though — hopefully a couple layers should be enough to keep the tee-junction safe from the weather. Most of the piping is 1″ interior diameter.

As for how the mount works, it will be installed vertically just below the peak of the roof on the side of the house. The two flanges will be secured to the side of the house using four-inch-long bolt screws. The screws will, of course, be going into studs accessible from inside the attic. The aluminum tube you see attached to the top of the mounting assembly is the base of the antenna; the antenna itself simply drops right into it once the mount is attached to the house. As for the decision of the overall placement, I’m putting the mount on the side of the house instead of on top of it so I don’t have to drill any holes through the roof, which could potentially cause some leaking.

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