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Carl and Jerry: The Black Beast
May 1960 Popular Electronics

May 1960 Popular Electronics

May 1960 Popular Electronics Cover - RF CafeTable of Contents

Wax nostalgic about and learn from the history of early electronics. See articles from Popular Electronics, published October 1954 - April 1985. All copyrights are hereby acknowledged.

Before a plethora of readily available and affordable electronic and mechanical components of all sorts was at your fingertips (on a keyboard), often times project builders and repairmen either did without, substituted "close enough" parts, waited a long time for mail order, drove long distances to a supply house, or did like Carl and Jerry did in this May 1960 Popular Electronics magazine adventure - they modified on-hand equipment to suit the need. Replacing the center conductor of a length of RG-58 coaxial cable in order to change its capacitance (and impedance) might seem like an extreme measure to take, but half a century go it was de rigueur with hobbyist of all sorts. Magazines of the era nearly always had monthly hints, kinks, tip, and suggestions features, enthusiastically (and sometimes motivated by a nominal monetary reward) provided by readers who had already reaffirmed the old adage of necessity being the mother of invention. As is author John Frye's normal practice, the reader is also treated to a lesson on an electronics subject, in this case a heterodyne system.

A comprehensive list of all the Carl & Jerry episodes posted on RF Cafe is at the bottom of the page.

Carl & Jerry: The Black Beast

Carl and Jerry: The Black Beast, May 1960 Popular Electronics - RF CafeBy John T. Frye W9EGV

The bright May morning found Carl and Jerry furiously pedaling their bicycles along a dirt road paralleling the river west of their home town.

"As I told you," Carl was explaining to his puffing companion, "yesterday afternoon I was trying out my new spinning reel along the path that runs between the bottom of the limestone bluff and the river. On the very first cast I let go of the line at the wrong time, and my favorite fla-fish lure sailed backwards into some scrub trees growing right against the base of the cliff. In trying to free the lure, I spied this narrow opening that looks like the mouth of a cave. I didn't have a flashlight; it was getting late; I knew my favorite pal would want to explore the cave with me; so I came home."

"What you really mean is that you were scared to go in by yourself," Jerry said with a sniff as he braked his bicycle to a sliding halt at a point where a steep path led down to the river.

Carl led the way down this path and then along a narrow, rocky ledge between the water and the cliff for a hundred yards or so. Then he clawed his way through some stunted trees and thorn bushes, and finally stopped triumphantly in front of an opening a couple of feet wide and about six feet high in the white limestone wall. The boys turned on their flashlights and very cautiously entered the narrow tunnel. It twisted and turned for some hundred feet and then suddenly emerged in a domed, nearly circular room at least twenty feet in diameter.

Carl and Jerry Indian paintings on cave wall - RF Cafe"Hey, Jer, look at that!" Carl breathed in a hoarse whisper as his flashlight beam came to rest on a dim, crude picture painted on the smooth white wall of the cave. As the circles of light from the two flashlights followed each other around the room, paintings and drawings as high as a man could reach were revealed on the walls.

"They must have been painted by Indians many years ago," Jerry whispered, shivering in the chill damp air of the cave. "Hey! What are we walking on?" he exclaimed as he tripped over something.

Carl shined his light down at their feet and then said softly, "Oh, oh!" The floor of the cave was strewn with large bloody bones with bits of flesh still clinging to them.

"Man, let's get out of here," Carl exclaimed as he headed for the tunnel opening. "Maybe the-the-the thing that lives here comes home for lunch."

The boys left the cave a lot faster than they had entered it.

"No ninety-pound weakling lives in there," Jerry asserted. "Those bones belonged to an animal at least cow-size."

"Yeah, and look at this," Carl added as he reached up and plucked a tuft of black coarse hair from a thorny branch hanging down over the cave. "Whatever it is, it's black and hairy and taller than we are."

"A black beast!' Jerry exclaimed in awe as he stared at the lock of hair in Carl's hand. "Let's find out what it is!"

"Like how?" Carl questioned dubiously.

"Hm-m-m-m, that's a good question. We can't stay down here and watch the cave without danger of the thing's scenting us."

"And probably gnawing on us like he did on those bones," Carl added. "But we can't watch from the top of the bluff because that overhang of rock conceals the cave mouth from sight up there."

"I got it!" Jerry exclaimed. "Remember when we used a simple capacitance relay to make that chicken-stealing coon at my uncle's farm take his own picture? Well, I've been experimenting with a new-type capacity relay described in the February Electronics World. We can camp safely on top of the bluff and let this relay tell us when anything or anyone enters the cave."

"What's special about this relay?"

"The sensing probe can be some distance from the relay and connected to it through a coaxial cable. The relay has two identical low-frequency r.f. oscillators: one fixed-tuned with a 300-µµf. capacitor, and the other tuned by a semi-variable capacitor in parallel with the capacitance of the coax line. This oscillator is set about 1000 cps higher in frequency than the fixed oscillator. The heterodyned difference beat between the two oscillators is amplified and fed through a low-pass filter to the control grid of a thyratron tube with a relay in its plate circuit.

"As long as nothing is near the probe, the low-pass filter prevents the 1000-cycle signal from reaching the thyratron and firing it; so the relay contacts remain open. When a body approaches the sensing probe, the additional capacity thus produced lowers the frequency of the tunable oscillator and also the difference-frequency heterodyne fed to the amplifier. This lower frequency passes readily through the filter, fires the thyratron, and closes the relay.

"There's only one joker," Jerry added thoughtfully as his eye measured the distance between the cave and the overhanging ledge. "The RG-8/U coaxial cable I've been using has a capacitance of 29.5 µµf. per foot. It's about twenty feet from the cave to that overhang where we could conceal the gadget and then run lamp cord from the relay contacts on up to the alarm at the top of the bluff."

"And 20 times 29.5 is 590 µµf.-far in excess of the 300-µµf. total capacity required to tune the oscillator to the right frequency," Carl finished.

"Of course, there are special coaxial cables with less capacity, but none in this town...

"I can solve your problem!" Carl interrupted as he started back toward the path. "I'll tell you about it on the way home."

Carl and Jerry modif RG-58 coaxial cable - RF CafeOnce home, they set feverishly to work. A twenty-foot length of RG-8/U was firmly anchored at one end and the remainder stretched out straight. The anchored end had its inner conductor tinned and a No. 30 wire carefully soldered to it. Heavy leads from a low-voltage high-current transformer were run to the two ends of the center conductor. By means of an autotransformer in the primary circuit, the current through the inner conductor was gradually increased until the conductor grew noticeably warm. Carl watched the dielectric material around the conductor carefully, and when he decided it was softened the proper amount by the heat, he unsnapped the leads from the transformer, grasped the end of the conductor with a pair of vise-grip pliers, and, walking backwards, easily pulled the conductor out of the cable and the No. 30 wire into the cable in its place.

Since the capacity of the cable was chiefly a function of the ratio of the inside diameter of the shield to the diameter of the conductor, replacing the conductor with the No. 30 wire drastically reduced the capacity of the cable - and incidentally raised its characteristic impedance. Now, with the reworked cable in place and the capacitance relay powered from batteries, the oscillator could easily be tuned to the proper frequency.

Soon the boys were pedaling slowly back toward the cliff burdened with gear for an overnight camp plus a long length of strong rope and Carl's .22 rifle. They tied the rope to a tree on top of the bluff directly above the cave, and Carl lowered himself to the overhang of rock. There he set up the capacitance relay with its battery power supply.

The coax cable was run down to the cave, and a lamp cord was run to the top of the bluff from the relay contacts. Both were concealed by vines growing on the face of the cliff. A small wire was connected to the bottom end of the coax inner conductor and artfully concealed around the opening in the cliff. Carl adjusted the variable frequency oscillator so that the relay contacts remained open until Jerry approached the opening; then they closed. They even closed when he tried to sneak in on his hands and knees.

The boys pitched their tent right at the edge of the bluff. They connected a battery and small light bulb in series across the two wires coming up from the relay contacts and fastened the lamp to the ridge -pole of their little tent. It was dark by the time they finished supper; and now, with nothing more to do except wait, the weariness resulting from the day's strenuous activities overtook them. After fighting sleep for a short time in the warmth of their campfire, they gave up, crept into the tent, and almost immediately lost consciousness.

Carl and Jerry hear noise in cave - RF CafeWhen Carl was snapped wide awake some time later by a light shining in his face, he instinctively felt that several hours had passed. Reaching over, he roughly poked his still-sleeping companion in the ribs. "Come on, wake up! Something's entered the cave and turned on the light."

Jerry sat up and rubbed his eyes sleepily. "Maybe we ought to wait until morning," he said with a shiver as he looked at the darkness outside.

"None of that!" Carl said sternly. "We go look now before he gets away. Remember this was your idea."

Stealthily the two boys, Jerry carrying the flashlight and Carl carrying the rifle, stole down the steep path and back along the narrow strip of rock leading to the cave. Not a sound could be heard except the singing of the night insects and the gurgling of the river.

"You go first with the rifle. I'll be right behind you with the light," Jerry suggested in a shaky whisper as they stopped in front of the yawning, pitch-black opening in the rock.

"Okay, but just don't get in my way if I suddenly decide I want out," Carl warned.

Slowly and cautiously the two boys entered the tunnel. Carl held the rifle stiffly out in front of him, and Jerry walked right on his heels with the glowing flashlight thrust through the crook of Carl's elbow.

Nothing happened until they reached the last right-angle turn in the tunnel. Suddenly Jerry clutched Carl's shoulder. "Listen!" he hissed. "Didn't you hear something?"

"How can I with you breathing in my ear like an asthmatic grampus?" Carl retorted as he edged around the turn.

The beam of the flashlight shining across the room revealed nothing, but as the two boys stepped from the tunnel, a pair of hairy arms reached out from the side and grabbed both the rifle and the flashlight, wrenched them out of the boys' hands, and sent the two stumbling forward to their knees in inky darkness. Carl was on his feet like a cat, but when he turned toward where he thought the tunnel opening was, he ran against a great hairy creature that smothered him in a vise-like grip.

"Kick him! Bite him, Jer," Carl shouted as he sank his teeth into a loose fold of the skin of the beast.

"I wouldn't do that," a deep chuckling voice answered. "I don't think my dad will like it if you chew a hole in his beloved old raccoon coat."

At this instant the flashlight came on and revealed a large smiling young man dressed in a bulky fur coat. Over at one side of the room was a camera on a tripod.

"So you boys want an explanation, and you've got one coming," the personable youth went on. "My name is Dick Palmer, and I'm a junior at the state university. About a month ago I stumbled upon this cave. I have a hunch these pictures were' made by the mound builders that used to live around here. Photography is a hobby of mine, and I instantly got the idea of photographing the pictures and selling them to one of the big picture magazines. I need the money to finish my college education.

"I've been driving back here every night I could get away from school to photograph these walls. It took a lot of experimenting with lighting and so on, but I finished the job tonight. Yesterday afternoon I had a little free time and drove over, but just as I got here, you," he said, nodding at Carl, "discovered the cave. I simply had to have a few more hours to finish up; so last night I stopped at a butcher shop and got a big bag of beef bones to spread around the cave and maybe convince you that this was the lair of a dangerous animal.

"When I heard you two coming down the tunnel tonight and saw that rifle, I decided I'd better disarm you first and explain later. You sounded a little trigger-happy."

"Why the fur coat?" Jerry asked.

"It gets darned chilly in here; so I've been wearing the old fur coat dad had in college to keep me warm. Now I've got a couple of questions. How come you're prowling around here at midnight, and how did you know I was in here?"

Come on up to our camp on top of the bluff, and we'll show you, and give you a cup of hot chocolate," Jerry offered.

"And you needn't worry that we'll blab about that cave," Carl added. "You found it, and it's your secret."

"Fine, men. If I'd known you were that sort, we could have saved all of us a lot of trouble."

"And goose pimples," Jerry admitted with a grin.

 

 

Posted January 28, 2022

Carl & Jerry Episodes on RF Cafe

Carl Anderson and Jerry Bishop were two teenage boys whose love of electronics, Ham radio, and all things technical afforded them ample opportunities to satisfy their own curiosities, assist law enforcement and neighbors with solving problems, and impressing – and sometimes toying with - friends based on their proclivity for serious undertakings as well as fun.

Carl & Jerry Their Complete Adventures from Popular Electronics: 5 Volume Set - RF CafeCarl & Jerry: Their Complete Adventures is now available. "From 1954 through 1964, Popular Electronics published 119 adventures of Carl Anderson and Jerry Bishop, two teen boys with a passion for electronics and a knack for getting into and out of trouble with haywire lash-ups built in Jerry's basement. Better still, the boys explained how it all worked, and in doing so, launched countless young people into careers in science and technology. Now, for the first time ever, the full run of Carl and Jerry yarns by John T. Frye are available again, in five authorized anthologies that include the full text and all illustrations."
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