“We’re on ten centimetres now. It’s going right through, as of course it ought to,” announced Barnett.
“This is unbearably scientific,” said Ann Halsey. “I’m going off to make tea. Come and help, Chris, if you can leave your meters and dials for a few minutes.”
Some time later while they were drinking tea and conversing generally, Leicester gave a startled cry.
“Heavens above! Look at this!”
“It’s impossible!”
“But it’s happening.”
“The ten-centimetre reflection is rising. It must mean that the ionization is going up at a colossal rate,” Marlowe explained to Parkinson.
“The damn thing’s saturating again.”
“It means the ionization has increased a hundredfold in less than an hour. It’s incredible.”
“Better put the one-centimetre transmitter on, Harry,” Kingsley said to Leicester.
So the ten-centimetre transmission was changed to a one-centimetre transmission.
“Well, that’s going through all right,” someone remarked.
“But not for long. In another half hour the one-centimetre will be trapped, mark my words,” said Barnett.
“Incidentally what message is being sent?’ asked Parkinson.
“None,” answered Leicester, “we’re only sending C.W. — continuous wave.”
“As if that explained everything,” thought Parkinson.
But although the scientists sat around for a couple of hours or more nothing further of note happened.
“Well, it’s still going through. We’ll see what it looks like after dinner,” said Barnett.
After dinner the one-centimetre transmission was still going through.
“It might be worth switching back to ten centimetres,” suggested Marlowe.
“O.K. let’s try again.” Leicester flicked the switches. “That’s interesting,” he said. “We’re going through on ten centimetres now. The ionization seems to be dropping, and pretty rapidly too.”
“Negative ion formation probably’ — from Weichart.
Ten minutes later Leicester whooped with excitement.
“Look, the signal’s coming in again!”
He was right. During the next few minutes the reflected signal grew rapidly to a maximum value.
“Complete reflection now. What shall we do? Go back to one centimetre?”
“No, Harry,” said Kingsley. “My revolutionary suggestion is that we go upstairs to the sitting-room, where we drink coffee and where we listen to music played by Ann’s fair hand. I’d like to switch off for an hour or two and come back later.”
“What on earth is the idea, Chris?”
“Oh, just a hunch, a crazy idea, I suppose. But perhaps you’ll indulge me for once in a way.”
“For once in a way!’ chuckled Marlowe. “You’ve been indulged, Chris, from the day you were born.”
“That may be so, but it’s scarcely polite to remark on it, Geoff. Come on, Ann. You’ve been waiting to try out the Beethoven Opus 106 on us. Now’s your chance.”
It was an hour and a half or so later, with the opening chords of the great sonata still ringing in their heads, that the company made its way back to the transmitting lab.
“Try the one-metre first, just for luck,” said Kingsley.
“Bet you that one-metre is completely trapped,” Barnett said as he clicked on various switches.
“No, it’s not, by John Brown’s body,” he exclaimed a few minutes later, when the equipment had warmed up. “It’s going through. It just isn’t believable, and yet it’s as plain as a pikestaff on the tube.”
“What’s your betting, Harry, on what’s going to happen next?”
“I’m not betting, Chris. This is worse than “spot the lady”.”
“I’m betting it’s going to saturate.”
“Any reasons?”
“If it saturates I’ll have reasons, of course. If it doesn’t there won’t be any reasons.”
“Playing safe, eh?”
“Signal going up,” sang out Barnett. “Looks as though Chris is going to be right. Up it goes!”
Five minutes later the one-metre signal saturated. It was completely trapped by the ionosphere, no power getting away from the Earth.
“Now try ten centimetres,” Kingsley commanded.
For the next twenty or thirty minutes the equipment was watched keenly, all comment silenced. The earlier pattern repeated. Very little reflection was obtained at first. The reflected signal then increased rapidly in intensity.
“Well, there it is. At first the signal penetrates the ionosphere. Then after a few minutes the ionization rises and we get complete trapping. What’s it mean, Chris?’ asked Leicester.
“Let’s go back upstairs and think about it. If Ann and Yvette will be kind-hearted and make another brew of coffee, perhaps we can do something towards licking this business into shape.”
McNeil came in while coffee was being prepared. He had been attending a sick child while the experiments had been going on.
“Why the air of great solemnity? What’s been happening?”
“You’re just in time, John. We’re going to run over the facts. But we’ve promised not to start until the coffee arrives.”
The coffee came, and Kingsley began his summing up.
“For John’s benefit I’ll have to start a long way back. What happens to radio waves when they’re transmitted depends on two things, the wave-length and the ionization in the atmosphere. Suppose we choose a particular wave-length for transmission and consider what happens as the degree of ionization increases. To begin with, for low ionization the radio energy streams out of the atmosphere, with very little of it getting reflected. Then as the ionization increases there is more and more reflection until quite suddenly the reflection goes up very steeply until eventually all the radio energy is reflected, none of it getting away from the Earth. We say that the signal saturates. Is that all clear, John?”
“Up to a point. What I don’t see is how the wave-length comes into it.”
“Well, the lower the wave-length, the more ionization is needed to produce saturation.”
“So while one wave-length might be completely reflected by the atmosphere, some shorter wave-length might penetrate almost completely into outer space.”
“That’s exactly the situation. But let me go back to my particular wave-length for a moment, and to the effect of rising ionization. For convenience in talking, I’d like to call it “pattern of events A”.”
“You’d like to call it what?’ asked Parkinson.
“This is what I mean:
1. A low ionization allowing almost complete penetration.
2. A rising ionization giving a reflected signal of increased strength.
3. An ionization so high that reflection becomes complete.
“This is what I call “pattern A”.”
“And what is pattern B?’ asked Ann Halsey.
“There won’t be any pattern B.”
“Then why bother with the A?”
“Preserve me from the obtuseness of women! I can call it pattern A because I want to, can’t I?”
“Of course, dear. But why do you want to?”
“Go on, Chris. She’s only pulling your leg.”
“Well, here’s a list of what happened this afternoon and evening. Let me read it out to you as a table.”
1 metre
2.45 p.m.
