“That cone-shaped loop is a highly directional affair I built so as to get away from this heavy traffic on San Francisco bay.”
He snapped over a filament-controlling toggle switch set into the long bench, and the beautiful set became instantly alive, transformed from a mechanically perfect but inanimate instrument of wood and wire to a living, glowing thing—a Twentieth Century horn of plenty, taking in at one end invisible and inaudible frequencies of electricity and releasing them as man-controlled music and speech.
Stan Ross plugged in his pair of phones and watched his friend, who was crouched before the superheterodyne, seeking by his trained manipulation of the dials to follow up the faint whistles which the set was pouring into his ears. Three stations four hundred miles to the south in Los Angeles roared in, one after the other, with an intensity sufficient to rattle the sensitive diaphragms of the head-sets. Dick slid his pair forward from his ears, but Stan, a veteran of the days when he and his fellow amateurs had sat long hours into the night with each others’ one kilowatt spark stations tearing into their heads from three-step audio amplifiers, only smiled.
“Pretty good, Dick,” he shouted. “Those stations down south are all piled together on almost the same wave. I didn’t think even the ‘het’ would separate ’em.”
“Sh-h-h!” cautioned Dick. “There’s the Calgary station away up north in Canada. I’m going to try the new loop, now—wait a minute.”
He removed his head-set and turned his attention to the egg-shaped affair previously referred to by Stan, connecting it in place of the outdoor antenna. The affair, Stan noticed, was shaped like half an egg, and rotated on a vertical axis at right angles to the normal horizontal line of an egg. Wire was wound on the parabolic wooden frame in such a fashion that the focus of the electrical parabola thus formed was fixed upon a point far out in space, in whatever direction the horizontal axis of the affair might be pointed.
Dick turned back to the set, now much quieter, and motioned for Stan to turn the loop, slowly. Stan stretched a tentative hand toward the handle on top of the parabola, expecting a fearful shriek in the phones. Nothing of the sort occurred—he gave a slight whistle of amazement.
“No body capacity?” he asked.
“Nope,” came the reply; “new kink in shielding I worked out.” Then as Stan stooped and peered into the frame, a puzzled look on his face: “No need of looking for metallic shields, because there aren’t any. Just something I happened to stumble on: reducing everything as much as possible to ground potential.”