CHAPTER XII
THE MARVELOUS SCIENCE
Inside of half an hour the boys were on a friendly footing with theyoung operator and felt as though they had known him a long time. Hewas only a few years older than themselves, and had been afull-fledged operator for about six months. The Mountain Pass stationwas his first assignment, and he was inordinately proud of thecomplicated apparatus that went to compose it.
"This is some little station that Uncle Sam has rigged up here, andwhile there are plenty of bigger ones, there are very few that aremore complete and up to date. Look at this three unit generator set,for instance. Compact, neat, and efficient, as you can easily see. Itdoesn't take up much room, but it can do a whole lot."
"It does look as though it were built for business," admitted Bob. "Isuppose that unit in the center is the driving motor, isn't it?"
"Right," said the other. "And the one nearest you is a two thousandvolt generator for supplying the plate circuit. The one at the otherend is a double current generator. That supplies direct current at onehundred and twenty-five volts and four amps for the exciter circuit,and alternating current at eighty-eight volts and ten amps for feedingthat twelve volt filament heating transformer that you see over therein the corner."
"Pretty neat, I'll say," remarked Joe.
"I think so," said the other, and continued to point out the salientand interesting features of the equipment. "Over here, you see, is ourmain instrument panel. These dials over here control the variablecondensers, and the other ones control the variometers. But there!" heexclaimed, catching himself up short. "I suppose none of you everheard of such things before, did you?"
The radio boys looked at each other, and could not help laughing.
"We've got a faint idea what they are, anyway," chuckled Bob. "We'vemade enough of them to be on speaking terms, I should say."
"Made them!" exclaimed the other, surprised in his turn.
"Sure thing," grinned Bob. "We've made crystal detector sets andvacuum tube sets, and----"
"And other sets that we never knew just how to describe," interruptedthe irrepressible Herb, with a laugh.
"Yes, that kind too," admitted Bob, with a grin. "But, anyway, we'vemade enough to know the difference between a variometer and acondenser."
"Well, I didn't know I was talking to old hands at the game," said theoperator. "I suppose I might have known that you wouldn't take thatlong walk out here through the snow unless you were pretty wellinterested in radio."
"Yes, we're dyed-in-the-wool fans," admitted Bob, and told theoperator something of their radio work.
"I'm mighty glad to know that you fellows do understand the subject,"said the operator, when Bob had finished. "I'm so enthusiastic aboutit myself, that it is a real pleasure to have somebody to talk to thatknows what I'm talking about. So many of the people who come here seemto be natural born dumb-bells--at least, on the subject of radio."
"Such as you took us for at first, eh?" asked Jimmy, with a grin.
"I apologize for that," said the other, frankly. "Please don't hold itagainst me."
"Personally, I don't blame you a bit," said Bob. "We can't expect youto be a mind reader."
"Well, then, that's settled; so let's look at the rest of thestation," said the operator, whose name was Bert Thompson. "This isour transmitter panel over here. It is very compact, as you can seefor yourselves."
He opened two doors at the front, one at the bottom, and raised thecover, thus exposing most of the interior mechanism to view.
"Here are all the fuse blocks down at the bottom, you see," Thompsoncontinued. "The various switches are conveniently arranged where youcan easily get at them while you are sitting in front of the panel.Then up here are the microphones, with their coils and wiring whereyou can easily get at them for inspection or repairs. Rather a neatlay-out, don't you think?"
"No doubt of it!" exclaimed Bob, admiringly. "We've never made a CWtransmitting set yet, but we hope to some day. A set like this wouldcost a pile of money, even if you made it yourself."
"Rather so," admitted the young operator. "It takes a rich old fellowlike Uncle Sam to pony up for a set like that."
"We're more interested in receiving sets just at present," said Joe."Let's take a look at that end of the outfit."
"Anything you like," said Thompson, readily. "That panel is located onthis side of the room."
"I suppose you use a regenerative circuit, don't you?" asked Bob.
"Oh, yes," answered the other. "That helps out a lot in increasing thestrength of the incoming sounds."
"I suppose you use a tickler coil in the plate circuit, don't you?"ventured Joe.
"No, in this set we use a variometer in the plate circuit instead,"said Thompson.
"Speaking of regenerative circuits, have you heard about Armstrong'snew invention?" asked Bob.
The operator shook his head. "Can't say that I have," he said. "Itmust be something very recent, isn't it?"
"Yes, I believe it is," said Bob. "I read about it the other day inone of the latest radio magazines."
"Do you remember how it worked?" asked Thompson, eagerly. "I wishyou'd tell me about it, if you do."
"I'll do my best," promised Bob. "The main idea seems to be to makeone tube do as much as three tubes did before. Armstrong found thatthe limit of amplification had been reached when the negative chargein the tube approaches the positive charge. By experimenting he foundthat it was possible to increase the negative charge temporarily, forsomething like one twenty-thousandth of a second, I think it was. Thisis far above the positive for that tiny fraction of a second, and yetthe average negative charge is lower. It is this increase that makesthe enormous amplification possible, and lets the operator discard twovacuum tubes."
"Sounds good," said Thompson. "Do you suppose you could draw me arough sketch of the circuit?"
"Let's have a pencil and some paper, and I'll make a try at it," saidBob. "I doped it out at the time, but likely I've forgotten it sincethen."
Nevertheless, with the friendly aid of the eraser on the end of thepencil, he sketched a circuit that the experienced professional had nodifficulty in understanding.
"You see," explained Bob, "with this hook up you use the regularArmstrong regenerative circuit, with the second tube connected so thatit acts as an automatic switch, cutting in or out a few turns of thesecondary coil. The plate circuit of the second tube is connected tothe plate of the detector tube through both capacity and inductance."
"I get you," nodded the operator. "According to your sketch the plateand grid of the second tube are coupled inductively, causing variationin the positive resistance of the tuned circuit."
"That's the idea exactly," agreed Bob. "You see, this is done by meansof the oscillating tube, the grid circuit being connected through thetuned circuit of the amplifying tube."
"Say, that looks pretty good to me!" exclaimed Thompson. "I wonder howArmstrong ever came to dope that out. I've been trying to getsomething of the kind for a long time, but I never seemed to get quitethe right combination."
"Well, better luck next time," said Bob, sympathetically. "There are alot of people working at radio problems, and it seems to be a prettyclose race between the inventors. Something new is being discoveredalmost every day."
"If you fellows are building sets, you're just as likely to make someimportant discovery as anybody else," said Thompson. "Thatsuper-regenerative circuit is a corker, though. I'm going to keep thatsketch you made, if you don't mind, and see if I can make a small setalong those lines. I have lots of spare time just at present."
"It will repay you for your trouble, all right," remarked Joe. "We'refiguring on doing the same thing when we get back home."
Jimmy had tried faithfully to follow the technicalities of the recentconversation, but his was an easy-going nature, disinclined to delvedeeply into the intricate mysteries of science. Herbert was somewhatthe same way, and they two wandered about the station, laughing andjoking, while Bob and
Joe and the young wireless man argued the meritsof different equipments and hook-ups.
"Say!" exclaimed Jimmy, at length, "I hate to break up the party, butdon't you think it's about time that we thought of getting back to thehotel? Remember we've got a long way to go, and it's four-thirtyalready."
"Gee!" said Bob, glancing in surprise at his watch. "I guess Jimmy isright for once in his life. We'll have to hustle along now, but we'lldrop in here often while we are at Mountain Pass--unless you put up a'no admittance' sign."
"No danger of that," laughed the other. "The oftener you come, thebetter I'll like it. This is a lonely place, as you can see foryourselves."
The radio boys shook hands with Bert Thompson, and after thanking himfor the trouble he had taken to show them the station, they startedback for the hotel at a brisk pace.
The days were growing very short, and it was after dark when theyreached the hotel. Very warm and comfortable it looked as theyapproached it, windows lighted and throwing cheerful beams over thewhite snow outside. A red glow filled the windows of the living room,and the boys knew that a big wood fire was roaring and crackling inthe big fireplace. As they drew close, a tempting aroma of cookeryreached them, and caused them to hasten their steps.
They had barely time to get freshened up before the dinner bell rang,and in a short time they were making havoc with as fine a meal as anyof them ever tasted.
When they told about their visit to the radio station, Edna and RuthSalper, the daughters of the Wall Street broker they had met in thesnowstorm, were among the most interested of the listeners.
"We find it so dull over at our house we are glad to come over herefor meals and to visit," said Ruth Salper.
"I suppose being in the woods in winter is rather dull," returned Joe,politely.
"Did you boys really know enough about radio to talk all afternoonwith the man in charge of the government station?" inquired Edna,curiously.
"Why not?" asked Bob. "Don't you think radio is a broad enough subjectto talk about for an entire afternoon?"
"Oh, I suppose it is," she admitted. "But why don't you share some ofyour fun with us?"