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, by pizza-sized satellite TV dishes.
To understand why an antenna is such a magical device, think of how it works. In its simplest form -- one of those whip antennas on port-able radios and TVs -- it's no more than a hunk of metal. There's no need to power it with electricity, yet it captures signals broadcast by a radio or TV station and translates them into music and pictures.
I've spent more than my share of time building antennas because of my ham radio hobby. Most of you will never have to embarrass yourself in front of your neighbors as I have -- using a casting rod in my back yard, trying to get a fishing line over a tree so that I could use that line to pull a rope over the tree so that I could hoist up the wire. I'll never forget the way the neighbors peered out their windows, wondering what kind of fish I hoped to catch in a tall oak.
But now that so many of us live and work in steel-and-concrete high-rises, there are practical reasons to learn about antennas. A friend 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 outlets.
The problem in both cases wasn't the strength of the signals. The buildings themselves -- the newspaper and the place where my friend lives -- were blocking the transmissions.
Here at the newspaper, we solved the problem by putting a simple wire antenna -- the kind you can buy at Radio Shack for $10 -- on the roof. Then we used coaxial cable -- the same kind of shielded cable used to pipe in cable TV signals -- 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 to pick up commercial shortwave stations or local AM broadcast. Its purpose isn't to amplify the signal, it's simply to grab the signal from a point outside the steel cage and pipe it inside.
You may be in the same boat. Even some homes have enough wire and steel in them to make any kind of radio -- shortwave or regular AM -- pretty feeble. The good thing about this problem is that an antenna is one of the few technological devices that the average person can build for himself. Unlike transmitting antennas, the shape and length of the wire you use isn't that important (in fact, with most portable radios, you actually don't want to have too big of an antenna -- the signal can overload radios built to work with a whip antenna).
So, whether you're trying to pull in a shortwave station from Beirut or 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.
The theory behind how antennas work is maddeningly complex, but building them isn't.
Pub Date: 7/13/98