"Yeah? Mirrors, or adding machines? You can't make an audio amplifier of a three million gain."
"I know it—at least not a practical one. But, we can probably use our audio modulator to modulate a radio frequency, and then modulate the driver with the RF. Then we hang a receiver on to the detector gadget here, and collect RF, modulated, just like a standard radio transmission, and amplify it at RF, convert it to IF, and detect it to AF. Catch?"
"Sure. And that gives me another thought. It might just be possible, if your idea is possible, that we can insert several frequencies of RF into the tube and hang a number of receivers on the detector, here."
Arden laughed. "From crystal detection to multiplex transmission in ten easy lessons."
"Call Charley and have him begin to concoct an RF stage for tube-modulation," said Don. "It'll have to be fairly low—not higher than a couple of megacycles so that he can handle it with the stuff he has available, but as long as we can hear his dulcet voice chirping that 'one, two, three, four, test,' of his, we can also have ship-to-Station two-way. We squirt out on the ship beam, and he talks back on the driver transmitter."
"That'll be a help," observed Wes. "I'd been thinking by habit that we had no way to get word back from the Relay Girl."
"So had I," confessed Walt. "But we'll get over that."
"Meanwhile, I'm going to get this alloy-selectivity investigated right down to the last nub," said Don. "Charley's gang can take it from all angles and record their findings. We'll ultimately be able to devise a system of mathematics for it from their analysis. You won't mind being bothered every fifteen minutes for the first week, will you, Wes? They'll be running to you in your sleep with questions until they catch up with your present level of ability in this job. Eventually they'll pass you up, and then you'll have to study their results in order to keep up."
"Suits me. That sounds like my job anyway."