A Simple Tilt-over

Mechanism for Mast Mounted Antennas

            When I first moved into my current abode, the question of antennas was an important factor in setting up my ham shack. Because of power lines that were in close proximity to the back of our home, any kind of wire antenna was out. We live in a hurricane prone area of the country, and the thought of wires waving about in the breeze, looking for power lines to hit, did not make me comfortable. I decided that a vertical antenna, mounted toward the front of the house was the only way to go. The presence of the house was enough to keep the vertical antenna from ever coming in contact with the power lines. I still needed a way to bring the antenna down safely when faced with an oncoming hurricane. A tilt-over mount seemed to be the only sensible option.

            There are a number of tilt-over mounts available from suppliers in the pages of QST and other ham radio publications. All of them appear to be very good and I have no doubt that many amateurs will choose one of these with great success. My specific situation was a little different, so I took an alternate path. Under the spot where I chose to erect my vertical antenna, the surface is solid concrete, my driveway in fact. This would make the installation of a commercial tilt mount problematic. The antenna mast, when erect, is anchored on two sides to the eaves of my roof. A different type of tilting mechanism was called for.

            My son-in-law, Gabe, who at the time worked for a new car dealer, came up with the solution. He found a steering shaft from a wrecked automobile which had a universal joint at about one third the way up the shaft. I took this to a local welder and had a pipe welded on to the shorter end of the shaft. Using a 10 foot length of masting material and a level, I determined the exact location for a hole to be drilled through the concrete pad, allowing for the diameter of the masting. This allowed the antenna and mast to be dead-on vertical when butted up against the eaves of the roof. A three quarter inch hole was drilled with a masonry bit. Testing with a blumb-bob  confirmed that it was in the correct spot.

            I then assembled the antenna (a GAP Eagle) onto the masting section and slipped one end of the steering shaft into the lower end of the mast. The other end of the steering shaft, with the welded on extension, into the hole in the concrete. Before I did this assembly, I made sure that the hardware that I was going to use to anchor the mast to the roof was already in place on the mast. The mast/antenna combination was then simply walked up to its vertical position and secured to the house. In order to present a more finished appearance at ground level, a plastic flower pot was cut and slipped over the mast and down to cover the universal joint. Coax runs from the Eagle and other antennas in that area of the house were dressed down the back side of the mast and attached with black wire ties. This presents a neat and clean view from the street.

            When a hurricane or tropical storm is forecast to be headed our way, it takes about ten minutes to release the mast from the roof, lower the mast and antenna to the ground, and secure it under the carport until the winds have past by. In over four years of operation, the antenna has worked flawlessly. During the 2004 Hurricane season, the system was lowered and raised 4 times. No damage to the antenna or to the house was noted.

            One caveat about this method is warranted. Make sure that the method used to secure the mast to the eaves of the house is fully capable of holding the system. I used a combination of U-bolts and mountaineering gear to secure the mast in two directions, North-South and East-West. I also added a third method  as a safety when lowering and raising the mast. Any one of these is strong enough to retain the mast, but redundancy is a must. If the mast/antenna falls, anything in its path will sustain damage. Don't ask me how I know, trust me on this.

            The sum total of all the parts and hardware used in this tilt-over mount came to about $30.00, not including the mast or the antenna. This is considerably less than the commercially available products. This system is not suitable for a freestanding mast away from a house or other structure unless guy ropes are used. That said, it does still obviate the problem of such a mast from having the base walk or shift during the erection process.

             When a house or other structure is available to secure the mast in an upright position, the "steering shaft" method is easy and simple. It can even be used with portable antenna masts used with emergency communications trailers or vans, where the base of the mast tends to be difficult to control. Securing the mast to the side or end of the trailer or vehicle can be as easy as a block of wood cut to accept the mast and secured temporarily or permanently to the trailer. The putting up of the antenna then becomes a one or two person job at the most. Not the least advantage is the removal of fingers and other portions of the anatomy from positions of risk at the bottom of the mast.

            I hope that this article gives you some ideas for your own situation. Other devices may work as well, such as automotive axles or drive shafts. The important part is the universal joint which makes the whole thing possible.