Radio Astronomy: Spare That Channel

"We should have started shouting back in 1947," says Radio Astronomer Charles Seeger. "But we didn't know then what we had hold of." Anxious to make up for this omission, the University of California scientist was in Washington last week shouting as loud as an amateur lobbyist can, crying for control of a tiny band of frequencies (608-614 megacycles) on the electromagnetic spectrum. Commercial-television men call that band Channel 37, and they long to fill it. Radio astronomers want it kept clear of all interference so that they can listen in peace to the whispering radio waves that come across it from the depths of space.

Until a few years ago, the young and exciting science of radio astronomy had the ultra-high-frequency part of the spectrum—which includes Channel 37—mostly to itself. Only a few TV stations sullied its waves, and their interference seldom bothered the comparatively crude early radio telescopes. But now the U.S. television industry is about to bulge into UHF, and modern radio telescopes have become increasingly sensitive. They can listen to exploding galaxies near the mysterious edge of the universe, but the slightest interference puts them out of action. A signal from a TV station thousands of miles away can be reflected off an airplane, or a satellite, or even a layer of air, and reach a radio telescope far over the curve of the earth with enough strength left to knock a delicate recording needle right off the scale.

To get an accurate, uncluttered view of the universe, radio astronomy needs at least one UHF window that is not blocked by scattered TV chatter. And if the FCC keeps Channel 37 clear of commercial broadcasts in the U.S., the International Telecommunications Union, which meets this fall in Geneva, is likely to do the same for the rest of the free world.