Thursday, June 24, 2010

I live in an area where outdoor antennas and towers are restricted ...

Q I live in an area where outdoor antennas and towers are restricted. I’ve noticed, however, that several of my neighbors have flagpoles; apparently they are acceptable. Is there any way to design a “stealth” antenna using a flagpole?

A Certainly! Flagpole stealth antennas are ham traditions that go back many years. Plastic or fiberglass flag poles make fine supports for vertical antennas that consist of little more than a quarter-wavelength of #10 wire snaked through the hollow center (see Figure 2). You can put a quarter-wavelength vertical antenna for 20 meters in a flagpole that’s only about 17 feet tall and feed it with 50-Ω coaxial cable buried in the lawn. And while you are digging, bury as many insulated copper radial wires as you can. Make the radials as long as possible, but don’t worry about their specific lengths. Quantity is what counts most.

I know of one ham who took a particularly clever approach with his flagpole vertical. He buried a remote-controlled antenna tuner in a weatherproof enclosure at the base of his 35-foot flagpole. As a result, he is able to load the antenna on 40 through 10 meters at the push of a button! Just more proof of the old adage, “Where there is a will, there is a way.”

Figure 2—A typical flagpole antenna.

From QST May 1999