Stratovision

"ttyymmnn" (ttyymmnn) 09/23/2020 at 12:35 • Filed to: planelopnik, planelopnik history, wingspan

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From the Wingspan Archives, originally posted November 19, 2015

In today’s world of global telecommunications and the Internet, we tend to forget that in the early days of radio and TV, before the advent of telecommunications satellites that could sit in space and bounce signals back down to distant points on the globe, TV and radio broadcasts ended at the horizon as seen from the top of the broadcast tower. That’s why broadcast masts are so tall. Following WWII, broadcasters wanted a way to extend their signal to a larger area. And to do that, they needed to get their antenna as high as possible, b ut they couldn’t build a tower 25,000 feet tall (the tallest radio masts today reach about 2,000 feet). The solution was Stratovision.

The concept, developed by Westinghouse engineers, was to broadcast a signal from the ground to an aircraft orbiting high in the sky while the aircraft relayed the signal to receivers on the ground hundreds of miles away. In 1944, Westinghouse teamed with the Glenn L. Martin Company, and together they performed early experiments using a !!!error: Indecipherable SUB-paragraph formatting!!! . Orbiting at 25,000 feet, signals originating in Baltimore, Maryland were received as far away as Norfolk, Virginia and Boston, Massachusetts. Following these successful tests, Westinghouse and Martin moved on to a larger aircraft. Martin modified an unarmed   !!!error: Indecipherable SUB-paragraph formatting!!!   by adding an 8-foot tall antenna on the tail to receive the signal from the ground and a 28-foot retractable boom antenna under the fuselage to relay the signal back to earth. Westinghouse filled the stripped-down Superfortress with radio and TV transmission equipment. Stratovision was ready for prime time.

Westinghouse and Glenn L. Martin employees pose in front of the B-29 Superfortress used in Stratovision tests

On June 23, 1948, while orbiting at an altitude of 25,000 feet over the city of Pittsburgh, Pennsylvania, Stratovision went live with a relayed broadcast of the Republican National Convention in Philadelphia that originated from WMAR in Baltimore. The television broadcast was received in a 525-mile diameter area that included nine states. T he radio signal was picked up as far away as Zanesville, Ohio, where receivers had been set up to demonstrate to the press that Stratovision could bring radio and TV into rural areas. Based on that experiment, Westinghouse engineers calculated that just eight aircraft, relaying the original signal from one aircraft to the next, could complete a transcontinental network. With fourteen planes, they could reach 78% of the American public.

A proposed string of Stratovision relay aircraft could provide coverage to much of the US

While Stratovision proved to be a technological success, underground coaxial cable networks connecting the East Coast with the Midwest were in place by 1949. Stratovision system became obsolete, and Westinghouse dropped the project in 1950. But the idea of flying transmitters to relay radio and TV signals did not end with the demise of Stratovision. In the 1960s, a non-profit organization used a modified !!!error: Indecipherable SUB-paragraph formatting!!! to rebroadcast educational programming to the Midwest. And the idea of high-flying broadcasting is alive and well in the Internet age with !!!error: Indecipherable SUB-paragraph formatting!!! . A subsidiary of Google has launched balloons that fly 12 miles above the Earth to bring Internet access to parts of the world that were unreachable before.

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If you enjoy these Aviation History posts, please let me know in the comments. And if you missed any of the past articles, you can find them all at !!!error: Indecipherable SUB-paragraph formatting!!! .

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Ash78, voting early and often > ttyymmnn 11/19/2015 at 10:49

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Finally, Leadville and Curtis join forces with the major metro areas of America!

Jcarr > ttyymmnn 11/19/2015 at 10:54

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Basically a precursor to satellite TV. Incredible.

ttyymmnn > Jcarr 11/19/2015 at 10:56

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Exactly. I like looking at the picture of the engineers in that one photo. How cool would it have been to be on that team? “Guys, this is what we want to do. Here’s your budget. It’s your job to figure out how. Now get to work.”

desertdog5051 > ttyymmnn 11/19/2015 at 11:21

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With underground cables going into service in 49, one would think that Westinghouse knew of this. Why would they invest so much time and effort into an almost obsolete system.

My only thought would be because cable would take some time to be be widely distributed.

The massive cost of keeping a fleet of planes operating for maybe 12 or more hours a day. Whew!

ttyymmnn > desertdog5051 11/19/2015 at 11:50

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I don’t think it was their intention to keep the planes in the air for long periods of time, just for special events, like the Republican Convention, or the Joe Louis-Jersey Joe Walcott fight of 1948.

GTStig > ttyymmnn 11/19/2015 at 11:58

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Just wanted to let you know that these posts are awesome. I surf through wikipedia all the time reading histories on all sorts of aircraft so these posts are right up my alley. The weekly this date in aviation posts are extremely appreciated as well.

ttyymmnn > GTStig 11/19/2015 at 12:11

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Thank you for those kind words, and thanks for reading. What started as a one-off post has morphed into a year-long project that encompasses my passion for both aviation and history. I’m having a lot of fun writing these, and I’m particularly pleased when somebody tells me they learned something. Thanks again.

RallyWrench > ttyymmnn 11/19/2015 at 13:07

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Man, the stuff we came up with. Just amazing.

ttyymmnn > RallyWrench 11/19/2015 at 13:17

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It makes me wonder if this gave scientists the idea for satellites, or if they already knew that satellites were the future, but there was no way yet to implement them.

The Powershift in Steve's '12 Ford Focus killed it's TCM (under warranty!) > desertdog5051 11/19/2015 at 15:49

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I’d also bet that they saw this as a technology demonstrator for the military, with the aircraft used as a central communication node for troops on the ground, something which the military is still using today.

MonkeePuzzle > ttyymmnn 09/23/2020 at 12:39

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I get it, but... WHY NOT BALLOONS!?

For Sweden > desertdog5051 09/23/2020 at 12:40

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Because the feds would pay for it

SBA Thanks You For All The Fish > ttyymmnn 09/23/2020 at 12:45

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What a crazy scheme with such a short half-life. Who would invest in such a terrible idea? That one’s just nutty...

Oh, wait a minute... this just in...

ttyymmnn > MonkeePuzzle 09/23/2020 at 12:47

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Back then, they probably couldn’t make balloons that regulated their own inflation to maintain a specific altitude to stay pretty much in one place. 

ranwhenparked > ttyymmnn 09/23/2020 at 12:56

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Thats what I'd guess. For things like sitcoms and game shows, the old process of going live for either the east or west coast and serving the rest of the country with a Kinescope recording of the live broadcast was perfectly fine and cheap. But, for important events that people wanted to see live and were much less useful to see after the fact, like political conventions or the World Series, this would have been fine.

gmporschenut also a fan of hondas > ttyymmnn 09/23/2020 at 12:57

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but with 500 radius is +/- 2 miles going to matter?

ranwhenparked > ttyymmnn 09/23/2020 at 12:59

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Sir Arthur C. Clark wrote of the basic concept of using artificial satellites for broadcast transmission a few years before this, but I dont know how seriously his idea was received at the time, or how widely known it would have been.

ttyymmnn > ranwhenparked 09/23/2020 at 13:01

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Smart guy. I just wish he was a better author. 

ranwhenparked > ttyymmnn 09/23/2020 at 13:05

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Off topic, but I’ve learned not to say the same thing about Isaac Asimov in polite company. Not that I don’t appreciate what he accomplished, or respect him on some level, I just never warmed to his stories. But, all his works have to be treated like holy documents in certain circles, God forbid anyone have a dissenting opinion.

ttyymmnn > ranwhenparked 09/23/2020 at 13:12

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I am an Asimov fan, and I’ve read the entire Foundation series three times (I think, at least twice). But I do recognized his shortcomings, and I would never get worked up over somebody not liking something I like.

What do you think of Frederik Pohl? I read Gateway when I was about 15 and it blew my mind. I’ve read a fair bit of his other stuff and really like it. 

RacinBob > ttyymmnn 09/23/2020 at 13:21

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The good news was that there are lots of low cost B-29's available for purchase. The bad news is they consumed a lot of engines due to failures. 

gmporschenut also a fan of hondas > MonkeePuzzle 09/23/2020 at 13:25

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I would think lightning strikes, a multiple Miles long cable would be super heavy, and with a cable, other static  interference.

MonkeePuzzle > gmporschenut also a fan of hondas 09/23/2020 at 13:32

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doesnt have to be a tethered balloon. If they were willing to send pilots up in planes, that cannot linger at all, why not send a crew up in a dirigible of some variety

wkiernan > desertdog5051 09/23/2020 at 13:44

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The cables were to link television broadcasting stations to network headquarters, not to bring signals to houses. You were supposed to be able to pick up a Stratovision broadcast on the teevee set in your house!

You may be too young to remember teevee antennas at all. When I was a kid, almost every suburban house had one. If you didn’t live close to a city with a broadcasting station, you might have had to install a directional antenna to get a usable signal. Typical directional antennas typically had a gain of 5 -15 dB, which means they were three to thirty times more sensitive in the direction they were pointed. I remember standing in the yard with a long stick, rotating the antenna while my Dad yelled “That’s better!” or “No, that made it worse” through the window from the living room , and also houses with two antennas pointed in different directions (one broadcaster’s antenna might be to the North of you while another was to the West) or motors to remotely rotate the antenna from inside your house.

If Stratovision had caught on, I imagine we might have see antennas angled slightly upward to the sector of the sky where the teevee plane was circling.

ranwhenparked > ttyymmnn 09/23/2020 at 13:52

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You know, I'm aware of who he was, but I don't believe I've ever read any of his work

AlfaCorse > MonkeePuzzle 09/23/2020 at 13:59

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Maybe a blimp would’ve worked, but I don’t think blimps operated above 10,000 ft, and a plane would could safely operate in worse weather conditions.

ttyymmnn > ranwhenparked 09/23/2020 at 14:04

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If you like science fiction, you would do well to check him out. 

f86sabre > ttyymmnn 09/23/2020 at 20:22

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f86sabre > f86sabre 09/23/2020 at 20:23

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Rock clap worthy. 

foxjohnc > ttyymmnn 10/07/2020 at 16:58

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I’m sure that power capacity was the main obstacle. Television broadcast equipment uses a ton of power even today, back then the primitive vacuum tube based equipment used many times more. Solar cells existed back then but were not commercially available so either batteries or some sort of generator would have to be carried inside the baloon. Even today I doubt solar cells could provide the power capacity required by the transmitters and relay equipment used for TV signals.