February 1964 Popular Electronics
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Wax nostalgic about and learn from the history of early electronics. See articles
published October 1954 - April 1985. All copyrights are hereby acknowledged.
In this "Pi in the Sky and Big Twist" episode of John Frye's "Carl & Jerry" series, the boys are by now into their college years at Parvoo University. Having been a mix of electronics experimenters, Ham radio operators, and high tech sleuths since high school times, the two friends find themselves once again participating in an event that depends upon cool heads and quick thinking. As is typical of Mr. Frye's tales, more than one topic is woven into the story, and usually real-life products, companies, and scenarios are incorporated in an effort to inform his readers. The Midwest Program on Airborne Television Instruction (MPATI) mentioned was an out-of-the-box idea in the pre-satellite era for broadcasting educational programming to areas that otherwise did not experience good quality over-the-air reception. Purdue University (note the similarity to "Parvoo U."), in Indiana, played a key role in the program where DC-6 airplanes were outfitted with a transmitter and a hydraulically stabilized antenna, and would fly for many hours at a time to provide rural areas with classroom instruction via TV. MPATI is a obvious spin-off of the Stratovision system experimented with by Westinghouse Electric Corporation and The Glenn L. Martin Company in the mid 1940s.
Carl & Jerry: Pi in the Sky and Big Twist
A Carl and Jerry Adventure in Electronics
By John T. Frye W9EGV
The February afternoon was unseasonably warm. Low clouds scudded across the sky and a gusty, damp wind was blowing from the southwest as Carl parked the car at the Parvoo University Airport.
"There's Bill's Cessna parked on the apron," Jerry said, climbing out of the car, "but I don't see Bill. You sure he wanted us to fly up-river with him to see the ice jam this afternoon ?"
"Sure I'm sure," Carl retorted. "There he is now over by that hangar. He's motioning to us. Let's see what he wants."
Bill Vardon, a senior at Parvoo, had a wealthy father back in Texas who had the poor taste to make his fortune in neither cattle nor oil. Instead, he had piled up dimes from a chain of root beer and hot dog stands extending clear across the country, but those dimes had bought Bill his own airplane and had made him a BMOC. He was, though, a "very right guy" in both Carl's and Jerry's eyes.
"Before we take off, I thought you electronic buffs might like a close-up look at the DC-six MPATI plane in the hangar here," tall, lanky Bill drawled. "I've got permission for us to go inside."
"We sure would," Jerry said promptly.
Both boys, of course, knew about MPATI, the Midwest Program on Airborne Television Instruction, that now was in its third year of operation. They knew that every Monday through Thursday morning of the school year a big DC-6 took off from its base at the Parvoo University Airport and climbed to its station at 23,000 feet over the little town of Montpelier in northeastern Indiana. There, staying within a ten-mile circle, it flew for better than five hours in a shallow figure-eight pattern so that turns could always be made into the wind. During this time two complete UHF TV transmitters inside the plane telecast simultaneous but different programs on channels 72 and 76. The video-taped educational programs telecast had been prepared by the finest TV instructors discovered in a nationwide talent search, and they covered such subjects as English, French, Spanish, history, literature, music, dramatics, science, and math. Because of the last subject, some wag had dubbed the program "Pi in the Sky." The educational telecasts were picked up and used by schools in six states within a 200-mile radius of Montpelier.
There she is, fellows," Bill said as they stopped beneath the wing of the plane that looked much larger inside the hangar than it did outside. "This plane is kept standing by in case something goes wrong with the other one flying on station. It's stocked with duplicate tapes and could take over the telecast as soon as it takes off and climbs to position."
"What's that long thing in the plastic cover sticking back beneath the belly of the plane?" Carl wanted to know.
"That's the twenty-four-foot transmitting antenna," Bill answered. "When the plane is on station, this is moved hydraulically to a straight-down position and a gyro keeps it within one degree of the vertical during all normal flight maneuvers. If it wasn't for that, the transmitted signal pattern would be tilting all over the place when the plane banks or climbs, and reception in many places would be pretty bad."
"One antenna for two transmitters?" Jerry queried with raised eyebrows.
"That's right. The klystron final stages of both transmitters - which operate at about five kw each - feed the same antenna through a diplexer arrangement that prevents interaction. That's just one of some of the 'firsts' the MPATI engineers have worked out."
"Must be a lot of valuable electronic gear inside that plane," Carl observed wistfully.
"I'm sorry I couldn't wangle permission for us to go inside the plane today," Bill replied, "but it's really something to see. Six and a half tons of transmitters, video tape equipment, operating consoles, and test equipment are bolted down in there. I say 'bolted down' because every bit of equipment has to be mounted solidly enough to take the stress of a very rough landing. Aviation authorities insist on this. At the same time, the stuff has to be shock-mounted to prevent the vibration of the plane from knocking the sensitive, high-gain circuits out of whack."
"It must take a lot of power to feed two complete TV transmitters," Jerry said thoughtfully. "Where does it come from ?"
"Back in the non-pressurized tail section are gas-turbine-driven, four-hundred-cycle generators that put out seventy-five kw. The standard TV transmitters had to be modified to use the four-hundred-cycle a.c., but they had to do it - higher-frequency power means a lot less iron in the generators and transformers, and a lot less weight."
"How many guys does it take to man this flying TV station?" Carl asked.
"Six. Three are flight crew, and the other three are technicians who operate the transmitters and keep an eye on performance. The signals are monitored all the time by technicians right here in the hangar, and they keep in touch with the TV guys in the plane through a radio circuit entirely separate from the one used by the pilot and the control tower. Any time the received signal gets bad, it's seen by the technicians on the ground and corrected by those in the plane if possible. Right now no live programs are shown, but they have a camera in the plane for transmitting test patterns between programs and to make slide announcements on program changes, transmission quality, and so on."
"How would you like this kind of set-up for ham TV experiments?" Carl asked Jerry.
"Great, but a little expensive to operate," Jerry replied laughingly.
"Well, men, we'd better be shoving off for a look at that ice jam," Bill broke in. "The flying weather is not so hot, and I want to be back at the airport before dark. The air is unstable, and there's an alert out for possible tornadoes up until midnight. I don't think there's anything to worry about, or I wouldn't go up, but I don't want to be up there in the dark playing blindman's buff with some twisters I can't see."
A few minutes later the boys were in the Cessna four-place plane waiting for permission to take off. Jerry sat to the right of Bill; Carl took one of the seats behind them. Permission was given, and they were off down the runway, gathering speed as melted snow-water splattered from beneath the wheels of the tricycle landing gear up against the bottom of the plane.
Bill, an expert pilot, took the plane off the ground quickly and smoothly. He circled and then leveled off well below the clouds and set a northeast course that followed the twisting ribbon of the Wabash River. The air was rough and bumpy, but a tail wind sped them along upstream until they reached the jam in the river some thirty miles from their starting point.
As Bill dipped a wing and circled lower, the boys could see the jam was a big one. Great cakes of ice had humped up to a height of several feet above the normal level of the river, and the dammed-up water had spread out across the fields on either side and was cutting new channels back into the river below the jam. Broken cakes of ice stood on end as far upstream as the boys could see, and Bill flew on up-river to find out how far the jam extended. No open water was seen until they were almost to the town where Carl and Jerry lived, nearly seven miles above where the jam started.
"Guess I'll fly south a ways and then cut across to fifty-two and follow that back into Parvoo," Bill said, banking the Cessna away from the river. "Say, what school's that down there?"
"Lincoln Township Consolidated School," Jerry said, looking down at the brick school building surrounded by soggy cornfields. "Look at the parabolic antenna on top of the building pointing over to the east. They must watch the MPATI programs. "
"Hey, Bill, look over to the right!" Carl interrupted. "Is that what I'm afraid it is?"
Bill took one look at the dark funnel that had suddenly lowered from the clouds two or three miles to the southwest and then banked the plane sharply away from the course he had been flying.
"It's a twister, all right," he said grimly, "and we don't want to tangle with it."
With awe the. boys watched the slender, writhing column of the tornado and the path of destruction it was leaving behind it. "It's sure traveling in a straight line," Carl remarked. "Look at it chewing up that telephone line! Say, if it keeps going the way it's headed, that school is going to be right in its path!"
Bill was already on the plane's radio calling the control tower at Parvoo and asking the operator to call the school and warn them of the approaching tornado. In a few seconds-they seemed like minutes to the boys watching the relentless advance of the evil thing - the tower reported it was impossible to get through to the school. The telephone lines were down. Probably they were the same lines the boys had seen destroyed.
"Maybe I can buzz the school and get someone's attention," Bill suggested, heading back toward the building.
"Not a prayer of a chance," Carl said, shaking his head. "With that big SAC base only ten miles away, there's hardly a minute of the day or night without the sound of some kind of plane around here. Even if you got someone outside, that grove of trees southwest of the school screens off the sight of anything coming from there. Could you land, maybe?"
Bill shook his head. "I can't land along the road because of the power lines. The fields are so soupy with this thaw that we would flip over as soon as our wheels touched. I sure hate ... "
"Wait! There's still a chance!" Jerry exclaimed. "Call the control tower and lave them phone the guys in the MPATI hangar. Ask them to have the technicians in the plane put warning slides in front of the announcement cameras for both transmitters. It's a slim chance, rut it's all we've got."
Bill was on the radio before Jerry finished. The alert control tower operator immediately grasped the plan. By the time he radioed back to tell the boys the MPATI plane was telecasting the warning, the tornado was scarcely half a mile away. Bill flew away from the storm at right angles to its path, and the boys watched helplessly as the funnel cut through the grove of trees, uprooting them and tossing them about as though they were straws, and then advanced directly on the school building.
For several minutes after the funnel struck the building nothing could be seen but flying debris; then, suddenly, .the funnel was sucked back up into the clouds as though satisfied with the devastation it had wrought. As the dust settled, the boys saw that a whole wall of the upper story on the north side had been torn out. Most of the roof was gone. As Bill circled the building at a low level, the boys could not see a single unbroken pane of glass.
But even as they watched, sick at heart, students and teachers came pouring up an outside basement entrance and spread out over the brick-strewn yard. A young man, apparently the principal, noticed the plane flying anxiously overhead and suddenly began shoving the students into groups. At first the boys in the plane were puzzled; then they saw what he was doing. The groups of students spelled out in ragged letters: "O.K." The plane carried three light hearts as it turned toward Parvoo.
When the boys landed, they learned the rest of the story that had been relayed to the MPATI people by the principal as soon as he had been able to get through on the telephone. A class had been watching a French telecast when the hastily-printed warning flashed on the screen of the receiver. The teacher told the principal, and he immediately herded all students into the southwest corner of the basement according to a prearranged disaster plan. Not a single child received a scratch.
"Everything and everybody got into the act today," Carl mused as he and Jerry drove back to their residence hall. "Ice jam, Bill's Cessna, the DC-six, the airborne transmitters, the receiver in the school, two-way radio circuits, telephone lines, the three of us, the MPATI crew and technicians, the tower operator, the school teacher, the principal - take away anyone of these essential links, and I hate to think of the results.
"Yep," Jerry agreed. "Roles from the hero, Pi in the Sky, villainous Big Twist!"
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 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."
Carl & Jerry Episodes on RF Cafe
- Pi in
the Sky and Big Twist, February 1964
Bell Bull Session, December 1961
Cow-Cow Boogie, August 1958
Picture, June 1955
- 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,
Santa's Little Helpers - December 1955
Two Tough Customers - June 1960
Transistor Pocket Radio, TV Receivers and Yagi Antennas, May 1955
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 February 3, 2020