It's hard for technology to shock people anymore. Once upon a time, folks sat open-mouthed at their first sight of a television set. When radio was first invented, some people seriously thought it might be the work of devils. And nowadays we have computers that can read handwriting, understand human speech and translate more languages than a platoon of U.N. translators.

So - compared to all that - I have my work cut out for me when I tell you that the most magical technological device that I know is an antenna. For most of you, an antenna is one of those ugly aluminum things that once sprouted on rooftops across America. It was replaced by cable TV and lately, in increasing numbers by the pizza-sized dish antennas used by satellite TV systems.To understand why an antenna is such a magic device, think of how it works. In its simplest form - maybe one of those whip antennas you find on portable radios and TVs - it's no more than a hunk of metal. There's no need to power it with electricity. Yet it captures tiny electrical signals broadcast by the radio or TV station and then translates those signals into music and pictures.

I've spent more than my share of time building antennas because of my ham radio hobby, sometimes stringing hundreds of feet of wire between tall trees just so that I could talk and listen to people around the world.

But now that a lot of us live and work in steel-and-concrete cages in the form of high-rises and apartment buildings, there are practical reasons to learn a little about antennas. An acquaintance here at the newspaper complained to me the other day that her fancy portable shortwave radio couldn't pull in many stations. And here at the newspaper, you can't pick up many of the local AM stations.

The problem in both cases isn't the strength of the signals. The problem was that the buildings themselves were blocking the signal.

Here at the newspaper, we solved the problem by putting up a simple wire antenna - the kind you can buy at Radio Shack for about $10 - on the roof. Then we used coaxial cable to connect the antenna to the radio.

And that's what I'll do with my friend. The outside antenna doesn't have to be fancy at all to pick up commercial shortwave stations or the local AM broadcast. In cases like the ones I mentioned, the purpose of the antenna isn't to amplify the signal, it's simply to grab the signal from a point outside the steel cage and then to pipe that signal inside.

So, whether you're trying to pull in a shortwave station from a station in Beirut or just listen to the Braves on your broadcast radio, consider draping a short length of wire out the window and connecting it to the antenna terminal on your radio.