September 1957 Popular Electronics
Table of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
published October 1954 - April 1985. All copyrights are hereby acknowledged.
began publishing a monthly electronics detective story series, "Carl and Jerry: A New Company is Launched," in the debut October 1954
issue. The two main characters, Carl Anderson and Jerry Bishop, were the
brainchild of John T. Frye, who also authored the "Mac's
Radio Service Shop." Carl and Jerry helped keep the
world safe from miscreants by way of their investigative prowess and deductive skills,
often with the assistance of their Ham radio skills. The
Hardy Boys were a couple of pikers in comparison. The theme
and ultimately solving of each mystery is centered around use of electrical and/or
electronics devices and methods, with a bit of intrigue and humor thrown in. If you enjoy short stories, then you will like the Carl & Jerry
Carl & Jerry: Electronic Shadow
By John T. Frye
Mrs. Bishop had told Chief of Police Morton that
Carl and Jerry were out in the back yard; and that is where he found them, busily
engaged in fastening a weird-looking object to the luggage carrier of Carl's bicycle.
The Chief stood for a moment unnoticed and then walked over to where the two were
"Hi, boys," he greeted them. "What are you up to?"
The boys glanced up with the startled, retrospective look the unexpected sight
of brass buttons and blue serge usually evokes from boys their age, but their faces
broke into welcoming grins as they recognized Mr. Morton.
"Hi, Chief; we're just getting ready to tryout a new gadget we've been working
on," Carl explained. "We call it 'the electronic shadow.'''
"'Electronic shadow,' huh? Sounds as though you two might be trying to muscle
in on my job. But let's have the details - how does it work?"
"Basically," Jerry explained, "the thing is a small working model of a gyro-compass.
It consists of this gimbal-mounted gyroscope that has its heavy but carefully counterbalanced
and easily turning rotor driven at high speed by this battery-operated electric
motor here on the end of the rotor shaft. The mounting and weighting are such that
the axle of the rotor is always maintained in a horizontal plane in spite of any
tilting of the surface on which the compass rests. Under these conditions, the spinning
axis of the rotor will align itself with the axis of the earth in such fashion that
both the rotor and the earth are turning in the same direction. One end of the rotor
shaft will continually point north no matter how the object on which the compass
is sitting is turned about.
"Next, note this small variable resistor mounted here on the frame supporting
the gyroscope mounting. It looks like an ordinary radio volume control, but there
are important differences. For one thing, the shaft of this variable resistor can
be turned around and around without meeting a stop. You can see that it only has
two terminals. One terminal is connected to one end of the resistance element; the
other goes to the slider that contacts this element. As the shaft is turned, the
resistance appearing between the two terminals rises gradually from zero to a maximum
value and then falls abruptly back to zero with each complete rotation.
"You can see here that the shaft of the variable resistor is fastened to the
gimbal holding the spinning rotor. Watch what happens as Carl turns the bicycle
around. See: the shaft is maintained in the same position by the gyroscope, but
the resistor case itself turns with the bicycle. That means that a different value
of resistance appears between the terminals for every point of the compass at which
the bicycle is pointed.
"The variable resistor is connected in the circuit
of a transistorized resistor-capacity type audio oscillator. The frequency of this
oscillator varies as the resistance of the compass-controlled resistor varies. That
means that as the bicycle is pointed in different directions, different tones are
produced by the audio oscillator. This oscillator modulates a small transistorized
transmitter whose signal can be picked up on a receiver down in the laboratory.
"Down there, too, is an identical audio oscillator containing a matching variable
resistor. The shaft of that resistor is locked in the same position as that of the
one up here which is controlled by the gyroscope. An arrow is fastened to the resistor
case. When that arrow points in the same direction in which the bicycle up here
is pointing, the tone coming from the receiver and the one coming from the oscillator
down there are at exactly the same pitch. If I want to know which way the bicycle
is pointing at a given instant, all I have to do is swing the arrow around until
the tone of my audio oscillator matches that coming from the receiver and note the
direction in which the arrow is pointing."
"WHEW!" Chief Morton exclaimed, mopping his brow. "I think I follow you, but
it isn't easy for a duffer whose knowledge of electronics is confined to how a flashlight
works. What does that little wheel riding on the rear tire have to do with it?"
"That's our distance-traveled indicator," Carl chimed in. "The little wheel turns
a flexible shaft that works a gear train. A cam on a shaft of this gear train closes
a pair of contacts momentarily every tenth of a mile and modulates the little transmitter
with a high-pitched 'beep' produced by another transistorized audio oscillator.
This allows the fellow down in the lab to keep track of the direction and distance
the bicycle has traveled at all times."
"Come on down to the lab and let's see if we can keep track of where Carl is
riding," Jerry invited.
"Fine," Chief Morton agreed with an eagerness that seemed a little strange in
one who had no knowledge of or interest in electronics.
Jerry had a map of the city spread out on the workbench of the basement laboratory.
He flipped on the receiver and the audio oscillator, then pecked on the basement
window and motioned for Carl to take off.
"He's heading south," Jerry announced, as he turned the arrow so that the two
tones were alike. There was a loud beep from the receiver. Jerry picked up a plastic
map-measuring instrument and put the little roller wheel on the map at a point just
south of where they were.
"This map is drawn to a scale of ten-inches-to-the-mile, and I have this map-measuring
gadget set to that scale," he explained. "Every time we hear a beep, I'll roll it
along the direction we know Carl is traveling until it shows a tenth of a mile.
That way we should be able to keep track of where Carl is at all times."
Doing this turned out to be easy, because Carl rode along streets that were laid
out in a rectangular pattern. When he turned, it was usually at right angles, producing
an abrupt change in the tone coming from the receiver. When this happened, Jerry
simply swung the arrow until the tones were again in step and changed the direction
in which he was moving the map-measurer to agree. All at once, though, the sound
coming from the speaker began to sound like: "Baweek, baweek, baweek."
For a moment a worried frown crossed Jerry's round face, then he broke into a
grin. "The smart aleck is riding around in a circle at this street intersection,"
he said, pointing at the map. A little later the indication showed that Carl was
riding straight for home. When the map-measurer had crawled back to the starting
point, Chief Morton opened the basement door just in time to hear the squeak of
Carl's brakes outside.
"That was a wonderful performance, boys," the chief said as Carl came down the
steps into the laboratory. "Now, as you may have guessed, I had a problem on my
mind when I came over here; but I'm almost convinced you two have come up with the
solution before even hearing the problem. To be sure, though, I have one question:
do you think that 'electronic shadow' will work as well in a car as it does on the
Jerry wrinkled his brow a minute and then answered slowly, "I can't see why not.
The distance-traveled roller could be driven from one of the car wheels. The diameter
of the roller would probably have to be changed so that the distance indication
would be accurate. But what do you have in mind?"
"Here's the story," the chief began. "Remember about a month back when a bank
bandit held up the First National Bank and got away with forty-seven thousand dollars?
If you do, you'll recall that we nabbed him with a roadblock about thirty minutes
after the robbery was committed; but he didn't have any of the actual cash with
him. Only some bonds were found on him. Somewhere here in town he had hidden the
cash. He's a pretty tough cookie, and nothing we can do will make him tell us where
the money is hidden. We had just about given up on this guy but something came up
recently that makes us think we may have a chance of uncovering the loot after all.
"A couple of days ago, a guard at the jail came to us with the story that this
bandit - his name is Palmer - had promised him half of that forty-seven thousand
if he would arrange a jail break. All the guard has to do is to allow Palmer to
overpower him and have a car waiting in the alley behind the jail.
"We're of half-a-mind to go along with this jail break in the hope of making
Palmer lead us to the missing money. The guard is willing to cooperate with us for
a share of the reward offered by the bank for the recovery of the money. The hitch
is that we're afraid of losing Palmer and the money, too! We're pretty sure he hid
it somewhere around those refining plants at the south edge of town. As you know,
there are acres of ground out there covered with huge steel tanks, steel towers,
etc., all of which reflect radio waves like mad. These reflections make the kind
of direction-indicating equipment we used on those car thieves useless. A trial
run proved that to us, for we lost the test car completely when it got near the
refineries. But I've got a hunch that this electronic tattle-tale of yours would
keep the finger right on Palmer. With it, all we have to do is hear the signal without
worrying about whether the signal heard is a reflection or not."
"Sure it will work!" Carl exclaimed, eager for the excitement to come.
"Let's make a test and see," Jerry suggested more cautiously.
So they did. They installed the compass in the car that Palmer would be driving
if the scheme were carried out, and this car was driven all over town while the
two boys and Chief Morton kept track of it at police headquarters. When the record
the driver kept of his course was compared with that plotted on the map at the police
station, the two records were found to agree in every minute detail.
"I'm sold!" Chief Morton announced. "We'll arrange the jail break for tonight
around midnight. You two boys be sure and be here around eleven. I'm going to have
every man I can on duty. Men on foot equipped with hand transceivers will be scattered
all around the refinery district. We'll have to depend on one of them being close
when Palmer gets out of the car to pick up the money. We can't crowd him too closely
with the squad cars or he'll get suspicious; but we can keep them in a circle around
him to make sure he doesn't slip through our fingers. If that happens, this town
will have a new police chief in short order."
Carl and Jerry, of course, were at the station
by ten o'clock. The chief explained that the guard had arranged with Palmer for
the break to occur at exactly midnight. A relay had been connected to the ignition
switch to turn on the "electronic shadow" when the motor was started and to cut
the transmitter off when the motor stopped.
As the clock hands scissored together at the top of the clock face, tension mounted
around the large map of the city spread out on a table near the radio dispatching
position in the police station. Carl was to operate the receiver and the direction-indicating
arrow of the audio oscillator. Jerry was to keep track of the car on the map. A
policeman with a stop watch was to keep a record of the time intervals elapsing
between the tenth-of-a-mile beeps. Chief Morton would move between the map and the
dispatcher so as to keep all forces coordinated for fast, smooth operation.
It was just six minutes after midnight when the audio tone suddenly burst from
the receiver in front of Carl. The fish had taken the bait!
The practice sessions paid off, and soon the boys were easily keeping track of
the car. Chief Morton, bent over Jerry, could see that Palmer was driving an aimless
course about town, apparently trying to throw any possible pursuit off his trail.
Before long, though, he started driving straight for the south edge of the city.
The chief kept a wide circle of squad cars around the position indicated on the
map by the crawling map-measurer in Jerry's hand.
As Palmer reached the vicinity of the refineries, the car seemed to have slowed
down, for there was an exceptionally long interval between two of the beeps. Then
he apparently turned down a side street, drove for about a block, and cut off the
motor. At any rate, the signal from the receiver disappeared.
Chief Morton sprang into action with a volley of commands intended to focus all
his forces at the spot where the car had stopped, but to keep them out of sight.
Suddenly there came from the speaker of the police radio the chilling report,
"There's no car here, Chief."
For a long, long minute, Jerry and Chief Morton stared at each other in dismay.
Then Jerry suddenly reached over and grabbed up the sheet of paper on which the
policeman had been keeping a record of the time intervals between beeps.
"That long interval!" Jerry exclaimed, and looked again at the map. "We thought
he was just driving slowly, but I'll bet he accidentally went past this alley, then
stopped and backed up. That means that the practice sessions paid off; soon the
boys were easily keeping track of the car. Chief Morton could see that Palmer was
driving aimlessly instead of being parked on this street here, he is really parked
in the alley ..."
Before the boy finished speaking, the chief of police had instructions crackling
through the air. It was only seconds until the reassuring word came back, "The car
is here all right. Palmer is just getting out of it and walking over to the side
of a warehouse. He's digging around in the sand with the toe of his shoe. Now he's
lifting out a tin box. Stand by. We're going to grab him!"
And grab him they did. The box contained the entire amount of cash taken from
the bank. As a squad car was bringing Palmer back to the jail, the chief explained
to the boys that they would undoubtedly receive a part of the reward.
"That's dandy," Carl remarked; "but our folks will just sock it away in the bank
for our college education. What gives us our kicks right now is the satisfaction
of knowing that for once we dreamed up a gadget that really worked."
"You mean some of your inventions don't work?" Chief Morton asked in wide-eyed
wonder. "That's hard to believe. You're batting 1000 with me. I've called on you
twice, and both times you came through."
"Come on, Blabbermouth; let's go home," Jerry said, taking Carl firmly by the
elbow and steering him toward the door. "You're so tired and sleepy you don't know
what you're saying. Good night, all," he called cheerfully back over his shoulder
as he hustled Carl out the door.
"He's lifting out a tin box. Stand by. We're going to grab him." And grab him
they did. The box contained all the cash taken from the bank ...
Carl & 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 lashups 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."
Carl & Jerry Episodes on RF Cafe
- Electronic Eraser,
- Electronic Trap, March
- Geniuses at Work, June
- Eeeeelectricity!, November
- Anchors Aweigh, July
- Bosco Has His Day,
- The Hand of Selene,
- Feedback, May 1956
- Abetting or Not?, October
- Electronic Beach
Buggy, September 1956
- Extra Sensory
Perception, December 1956
- Trapped in a Chimney,
- Command Performance,
- Treachery of Judas, July
- The Sucker, May 1963
- Stereotaped New
Year, January 1963
- The Snow Machine, December
Education, July 1963
- Slow Motion for
Quick Action, April 1963
- Sonar Sleuthing, August
- TV Antennas, August 1955
- Succoring a Soroban,
- "All's Fair --", September
- Operation Worm Warming,
Stomping, March 1962
- The Blubber Banisher,
- The Sparkling Light, May
- Pure Research Rewarded,
- A Hot Idea, March 1960
- The Hot Dog Case, December
- A New Company is Launched,
- Under the Mistletoe,
- Electronic Eraser,
- "BBI", May 1959
- Ultrasonic Sound Waves,
- The River Sniffer, July
- Ham Radio, April 1955
- El Torero Electronico,
- Wired Wireless, January
- Electronic Shadow,
- Elementary Induction,
- He Went That-a-Way,
- Electronic Detective,
- Aiding an Instinct,
- Two Detectors, February
- Tussle with a Tachometer,
- Therry and the Pirates,
- The Crazy Clock Caper,
Posted May 10, 2019