April 1961 Popular Electronics
Wax nostalgic about and learn from the history of early electronics. See articles
published October 1954 - April 1985. All copyrights are hereby acknowledged.
You can still buy from Moog today the same sort of
Theremin that was described in this 1961
Carl & Jerry episode. Ever the early adopters of breaking
technology, the teenagers exploit the motion-sensitive feature
of the Theremin in hopes of improving Carl's basketball game.
As usual the boys, in mock dialog, describe the Theremin's operational
theory for the benefit of readers not familiar with the musical
instrument. They do not, however, mention that the device is
named after its Russian inventor,
Léon Theremin, who patented the device in 1928. Read on
to discover how a Theremin strapped to Jerry's back was used
to help Carl be a better free-thrower.
Carl & Jerry: Therry and the Pirates
By John T. Frye
The huge high school gymnasium was dark and empty except
for a spotlighted basketball goal down at one end of the floor
and the shadowy figures of Carl and Jerry standing beneath it.
Carl was clad in his basketball uniform, but Jerry was wearing
his usual shapeless sweater and fashionably beat-up cords.
"I must have been out of my cotton-picking mind when I let
you talk me into this caper," Carl muttered while Jerry busied
himself strapping a strange apparatus to the broad back of his
athletic chum. Belts around Carl's waist and chest held a broomstick
erect at his back so that the handle rose a few inches above
his left shoulder. Fastened at the top of the handle was a small
aluminum chassis box with dials, jacks, and switches on the
back of it. Two quarter-inch aluminum tubes stuck out the top
of the box and went straight up, side by side and some six inches
apart, for a distance of a couple of feet.
"You want to improve your free-throwing, don't you?" Jerry
demanded, as he threw a switch on the little box. "Let's go
over and sit down for a few minutes while those oscillators
"Yeah," Carl agreed, seating himself gingerly on the substitutes'
bench, "but I keep wondering if the Globetrotters started this
way. Tell me again about this thing riding my back."
"The little box contains the tone-generating sections of
theremins," Jerry replied, stretching out on his back and
closing his eyes. "You know what a theremin is and how it works,
don't you ?"
Theremin that appeared in the January 1961 edition of
"I know it's a musical instrument played by just waving the
hands near a couple of rods or plates. I think the motion of
one hand controls the pitch of the tone produced, and the motion
of the other controls the volume. But I've only a very foggy
notion of how this is done."
"All right, let's think about the tone-generating portion
first," Jerry suggested. "It consists of a couple of oscillators
operating around 150 kc. In this case the oscillators are transistorized,
because I copied them from a construction article on a transistorized
theremin that appeared in the
January 1961, issue of
Electronics World. .
"The outputs of both oscillators are fed to a diode mixer
that combines them and produces an audio signal with a pitch
equal to any difference in frequency between the oscillators.
One oscillator stays on the same frequency all the time. The
other has a sense antenna, usually a metal rod or tube, connected
to its frequency-determining circuit so that any capacity between
this antenna and an object brought near it, like a human hand,
adds capacitance to the circuit and lowers the frequency of
the oscillator. The amount of capacitance depends on how near
the hand is held to the sense antenna - the closer the hand,
the greater the capacitance.
"This, of course, changes the difference-frequency between
the two oscillators and so changes the pitch of the tone produced
by the instrument. Since the actual amount of hand-capacity
is quite small, a circuit is used with the sense antenna that
effectively amplifies this hand-capacity. When the variable
oscillator is tuned to zero-beat the fixed oscillator with the
hand away from the sense antenna, moving the hand toward the
antenna from about a foot and a half away will cause the audio
tone to go up several octaves from a very low pitch."
"I'm with you so far," said Carl, "but how does moving the
other hand change the volume?"
"The volume control circuit uses another low-frequency oscillator,"
continued Jerry. "A resistor connects the tank circuit of this
oscillator to a series-tuned circuit resonated near the oscillator
frequency. The resistor and the tuned circuit form an r.f. voltage
divider across the oscillator tank. A diode rectifies any r.f.
voltage appearing at the junction point, and the d.c. thus produced
is applied as bias to a transistor amplifying the signal delivered
by the tone-generating portion. When do you think the least
r.f. voltage will appear at the junction of the resistor and
tuned circuit ?"
"When the circuit is tuned to the resonant frequency of the
oscillator," Carl answered promptly. "A series-tuned circuit
has a very low impedance at its resonant frequency, but this
impedance goes up rapidly as the circuit is detuned either way."
"Exactly right. The tuned circuit is adjusted to resonance
with the left hand away from a metal plate that is connected
to the tuned circuit. Under these conditions, practically no
bias voltage is produced, and the amplifier works at full output.
"As the hand is brought nearer the plate," Jerry went on, "hand
capacity causes the resonant frequency of this tuned circuit
to go lower than the oscillator frequency. The impedance of
the series-tuned circuit rises, as does the amount of bias voltage
developed. This voltage reduces the output of the amplifier.
In fact, when the hand is about an inch away from the volume
control plate, the amplifier is completely cut off.
"Now this volume-controlling action is interesting, but it
doesn't concern 'Therry' here. He just has two tone-generating
systems, each with its own antenna, and without any volume control
portions. Let's see if he's operating."
Jerry plugged a pair of stereophonic earphones into a jack
at the rear of the aluminum box and moved his hand experimentally
around the two antennas. Satisfied, he handed the earphones
"I spent a lot of time making those two tone generators perform
exactly alike," Jerry said. "Notice that when I move my hand
away from the middle of the two antennas along a line that keeps
it equally distant from both, the tones heard in both ears stay
exactly in step for all positions of the hand. But when I deviate
from this line, even a little bit, the tones are different.
The tone coming from the antenna nearest the hand is higher
in frequency. Now let's see if Therry really works."
They moved to the foul circle, and Carl started pushing up
shots at the basket. Jerry, wearing the earphones, kept twisting
the broomhandle until the antennas were in a position where
the sound he heard when Carl made a basket was a single-tone
eeeoooop, This was produced by the rapid movement of Carl's
left hand going up at an angle from the bottom center of the
two antennas and keeping equally distant from them until the
ball left his fingers.
At this point Jerry placed the earphones on Carl's head,
and connected a tape recorder to the output of one of the theremin
units. Then he fed balls back to Carl while the latter continued
pushing them up at the rim of the basket. Maybe it was chance,
maybe it was that listening to the sound somehow unlocked the
foul-shooting block that Carl had recently developed; but his
percentage of goals went up sharply soon after he put on the
earphones. Finally he hit eleven in a row, and then closed his
eyes tightly and lifted a twelfth straight through the hoop
guided only by the sound in the earphones.
"I'll quit on that one," Carl said with a pleased grin as
he began to unstrap the device from his back; "but I believe
old Therry here helps. Anyway, let's all three. of us do this
some more every night until the big game Friday."
Jerry made an endless loop of tape carrying the theremin
sound of a perfect shot, and each evening before Carl started
practicing, Jerry would let this run a few times over the gymnasium
sound system, to "prime the pump" as he put it. Carl's percentage
of good shots not only continued at the same high level but
The theory was that Jerry permitted another sense to be brought
to bear on the acquiring of a skill. Carl's eyes could follow
critically the arc of the ball; from his muscles and joints
came a kinesthetic sensation of the wrong and right movements;
and now his ears could hear the difference between hits and
Friday night the gym was filled to the rafters for the game
with the Pottsville Pirates. The Pirates and the hometown Huckleberries
had been traditional enemies for many years, and as far as either
town was concerned this was the most important game of the season.
Jerry, as usual, was working the sound system; and he watched
anxiously to see if Carl would be in the starting line-up. He
breathed a sigh of relief as he saw his chum preparing to jump
center against a rangy Pirate at least two inches taller, but
he couldn't help thinking Carl looked a little naked without
Therry strapped to his back.
The game was fought bitterly right from the start. At the
half, the Huckleberries led by three points; but in spite of
everything they could do, the Pirates relentlessly overhauled
them and forged ahead by two full field goals at the end of
the third quarter. When the Huckleberries came running out on
the floor at the beginning of the last quarter, Jerry could
see that Carl's jaw was set in a grim line.
Carl and the other Huckleberries played furiously, but the
Pirates fought back just as hard. The battle raged up and down
the floor as the seconds ticked away on the time clock. The
score was 50 to 49 in favor of the Pirates. Finally, when the
timekeeper was holding his pistol aloft with his eyes glued
to the clock, Carl stole the ball from under the Pirates' goal
and came charging down the floor. From far out, he leaped into
the air and fired a desperate long shot at the basket as clawing
Pirate hands tore at his wrists and the final gun rang in his
The ball hit the backboard, fell down to the rim of the basket,
rolled tantalizingly around it, then fell outside. A deep groan
arose from the Huckleberry rooting section. But the referee
was blasting away on his whistle and holding up two fingers
while he waved Carl to the foul circle.
It was very quiet in the gymnasium as Carl deliberately bounced
the ball a couple of times before trying his first free throw.
Jerry could see that the muscles in his shoulders were bunched
with tension. When Carl attempted the shot, it did not even
come close; and a murmur of disappointment ran over the crowd.
Up in the sound booth, Jerry made a quick decision. He switched
the tape recorder into the P.A. system and started the loop
of tape on it moving past the tape heads. "Eeeeoooop, eeeeoooop,
eeeeoooop!" was the sound that suddenly burst from the speakers,
and hundreds of eyes turned to shoot indignant looks at Jerry.
But the latter, watching his friend down on the floor, saw the
tenseness go out of Carl.
Confidently Carl pushed the ball up in one easy, effortless
motion. The ball swished through the hoop without touching it!
The ensuing overtime to break the tie was really anticlimactic.
Nothing could stop the exuberant Huckleberries now, and the
final score was 58 to 52 in their favor.
The fans swarmed around Carl and literally carried him off
the floor. But as they surged past the sound booth, Carl looked
at Jerry and threw up a long arm to make an appreciative, triumphant
gesture with a circled thumb and forefinger. Therry was being
given the credit for winning the game!
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 August 27, 2014