" THE CREATION AND BEHAVIOR OF RADIO WAVES " 1942 U.S. ARMY SIGNAL CORPS TRAINING FILM XD13914
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- Опубликовано: 26 авг 2024
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This 1942 black and white, partially animated film was produced by the U.S. Army Signal Corps (USASC) during in collaboration with the Chief of Air Corps explains “the creation and behavior of radio waves” and antennas during the WWII era (TRT: 10:47).
Opening title card: “Official War Department Training Film 1-474 Restricted” (0:06). A large radio tower extends high into the clouds. Title appears: “Radio Antennas” (0:19). A transparent dish atop a radio tower (0:37). A radio transmitter on the underside of an aircraft. Two more atop an airplane. A vertical antenna pole on a small plane (0:41). Three radio towers stand in an open field (0:49). A compass is held open near a wire. As the compass approaches the wire, the needle rotates (0:52). Animation: A series of concentric rings with clockwise arrows encircle a black pole and pulsate. Then again, with counter-clockwise arrows. Repeat alternation at higher speed (1:06). A clear rod picks up strips of paper using static electricity (1:29). Another animation illustrates a magnetic field and the forces of attraction around the rod (1:40). The concentric circles and the illustration of the rod (1:53). A diagram of a circuit with a battery, a condenser, and an open switch (2:11). Concentric circles appear around the circuit as the switch is closed. They disappear when the switch is opened. Then, the battery begins to rotate, alternating positive and negative polarity (2:23). The condenser emits waves from both poles (3:22). The condenser is enlarged within the diagram of the circuit to show detail of the wave shape (3:28). The condenser, centered, extends symmetrical waves across both sides of the screen. It rotates as the waves flash (3:36). An illustration of a high frequency generator. It sends out a series of broad waves at an accelerating pace (3:50). An illustration of a radio tower emits similar waves at high speed (4:52). Dissolve to pace the waves slowing. The space between waves is measured with text and an arrow, “wavelength.” Animation repeats with progressively shorter wavelengths (5:05). Title card: “Radio Waves in Space” (5:24). Animation shows a dotted line emitting from a radio tower skyward in a straight diagonal line, then again, reflecting or ricocheting off the ground (5:33). A wider view, showing the earth’s curvature, the word “ionosphere” appears above. Waves bounce off of it (5:53). A radio wave reflects off the earth’s atmosphere multiple times in a zig-zag pattern (6:19). Higher frequencies are visualized as not reflecting (6:59). Return to live-action footage of a radio tower with wide, horizontal antennae at its peak (7:21). Animation of a radio tower sending waves earthward, labeled “ground wave” (7:34). A wider view shows a tower (not to scale) broadcasting waves across the United States, encountering earth’s curvature (7:50). Another wave reflects above the U.S. and lands on the east coast (8:18). Text illustrates “skip distance” between waves (8:29). Multiple reflections (8:35). A map shows waves emanating from Cincinnati and spreading to St. Lous, Kansas City, Denver, with a “zone of silence” in between (8:46). Animation of radio tower waves going over a mountain and landing in a city (9:04). Again, missing the city. Ground waves reach the city (9:30). Two paths of waves converge and overlap (9:55). A lattice of overlapping and criss-crossing waves (10:07). The live-action radio tower returns (10:13). An air traffic control tower. Medium shot of a U.S. Consolidated B-32 Dominator bomber aircraft (10:22). An air traffic controller and the B-32 in full view among the clouds (10:24). Title card: “End of Training Film 1-474” with the seal of the Signal Corps (10:33).
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I love army videos because they are straight forward and straight to the point no fu... bulshit just pure knowledge
Sadly, I don't think anyone makes anything even close to this in terms of learning per unit of time, at the moment.
The closest I've found would be current-day lectures which can vary depending on who it is and what they're talking about, but certainly nothing 'produced' like this was.
Anything produced today seems like 1/3 of it can be focused on whoever the host is.
Another 1/3 aimed at entertainment, such as ridiculous demonstrations to convey concepts, but end up spending 80% of that time focused on the creation of the demonstration instead of getting on with the point.
In the best of situations, the other 1/3 will be some decent info, that hopefully is up to date and correct (Looking at you Jim Al-Khalili hand picking one interpretation of quantum physics and stating is as fact)..but generally it's just the same info and even sometimes the same sentences from a previous documentary on the same topic.
Enough ranting for now; It's just sad to see more than anything else... but at least we still have these!
They had be. They had to train as many recruits as possible in as short as time as possible.
@@pretoasted Yes! Well said !
Why do you compare military training to civilian training ?? Dopey 🤔🤐
@@jimmyohara2601 because I don't care if it is a military or civilian or marsian video?! I just want to understand and nothing else counts. Eveything which works works. Btw. why are you rude to me ?
This was taught better in 1942 than it is today haha
Aghh, bhoolshAt. You didn't even take notice @School. Those lessons been so in school/s for decades. 🤐
No doubt
I love how clear those videos are !!!
Ha..better than more than a few radio societies presentations...!!!!!
Very nice and useful information.
Absolutely amazing! I wonder if this video was used when my father was in training in Signal Corps, Korean War, Augsburg, Germany circa 1953.
Thanks for sharing, guys! Good job 👏
The technology of the medium then (film/animation) was as amazing and advanced as was the topic. You couldn't just pull out your phone and do a selfie video explaining a topic. Then consider the delivery of that film. The only way people could see these was to physically go some where and watch it on a screen. Some guy had to thread the machine, set the audio loop, etc. Some bunch of humans had to somehow hand deliver that film to wherever it was seen. How about the music! It wasn't canned in those days. It was typically real musicians playing, recording, while watching the film sequences. The voice over! Before we did much close mic recording of spoken voice (Good evening Mr and Mrs America and all the ships at sea...). Recording and editing film and audio in 1942 was just a "little bit" different than today...:-)
Thanks previous generations of people who figured stuff out.
You still can't pull out a phone and make a professional feature film; there are hundreds of details that the average person doesn't think of. I wonder where this particular film was intended to be shown? What was the expected audience? Was it a short subject to be shown in a movie theatre between the main features? Shown in a school classroom? Did the organ dealers have projectors to show this to prospective customers?
@@gregm.857 In theory, you COULD pull out a phone and if you were a skilled director, photographer, editor, and/or had a large and expensive crew of same, make a professional feature film. Surely it would be horrendously more time consuming.
Perhaps more to point - Even using 70mm film cameras, the technology of today is gazillions of times more refined than then. Just tripods, for example. They've gone from rickety, wooden things to motor powered, hydraulically dampened, GPS located instruments. Film drives, audio recording/editing/synching...those early guys were giants. We stand on their shoulders today. We made the equipment lighter and smaller, but they started from ZERO and figured out how to do it. With drafting tables and slide rules, not computers or CAD/CAM.
@@DrLumpy I stand by my original premise: "You still can't pull out a phone and make a professional feature film." The phone is no substitute for a complete lighting kit. It's no substitute for a quiet sound stage. It's no substitute for a multi-track audio mixer and $50k or $100k worth of microphones. A phone might be able to record a passable image, but that is only a tiny part of a feature film. For a long while, a lot of the major innovations in audio came from the motion picture industry (e.g. 4-channel Fantasound in 1940). The technicians back then came up with the basic process which has been used for years, until NLE and HD video came on the scene. There were crane dollies, track dollies, incredible mic booms, and lots of "tricks of the trade" that have carried down thru the years with some refinement as new technology evolved.
At any rate, you need more than a picture (from a phone or from an HD camera) to make a feature film.
The foolishness of today's people.
Having access to knowledge is different than education and understanding.
It's the difference between being ignorant and being stupid.
EXCELENTE ARQUIVO 🇧🇷👍
Right Hand Rule for induced magnetic fields indicates that if the conventional current is flowing in the direction your thumb is pointing then the magnetic field's direction is the same as the direction your fingers are pointing as you curl them towards your palm. The drawing at the start of film is backwards of that.
Drawings are correct. Many of these older films illustrate electron flow, not conventional current. Ben Franklin postulated electrical charge flowed from positive to negative, and this had held as conventional current. What the drawings show is actual charge flow of the electrons from negative to positive.
Fantastic.
The strong station in Cincinnati was 700 AM WLW 500,000 WATTS in its heyday. Powel Crosly's pride and joy. Known as THE NATIONS STATION then. So much power that they were making Canada mad, with there broadcasts going in and disrupting there broadcasts.
THEIR broadcast, dopey. Not there, Spazz 🤐
And WLW received Congressional approval to do so, it was taken away due to complaints from other Broadcasting companies. My Grandfather worked for Crosley in the Foreign Department.
Crazy to think this video was made while ww2 was raging on
I wish that the ranges of frequencies were given when talking about different wave lengths.
This film was about radio waves GENERALLY, Not any particular band But, Since it's a WW2 era film, It's certainly geared to 1940's military coms. That would have been in the good old "HF" band (3 Mhz -30 Mhz) This is also known as the "Shortwave" spectrum, Even though we generate MUCH shorter waves now, The name stuck. (Broadcast AM is known as "Medium Wave") Useless bar trivia: Truckers on CB are technically using shortwave radio transceivers! Wave length is shorter as the frequency gets higher, This is why you don't have a telescopic antenna on a Bluetooth receiver but you would on a standard FM radio. Bluetooth is 2400 MHz to 2483 MHz, "FM radio" is 88 MHz to 108 MHz. The lower frequency, the longer the antenna! To find the actual wave length of a given frequency: use this formula: Wavelength = 300 / Frequency in MHz. for example if I am listening to KDKA-AM 1020 KHz in Pittsburgh and want to know what the wave length is: it's 300 / 1.020 MHZ = 294 Meters (rounded.) Here is a more precise tool that converts ANYTHING to ANYTHING 😊 www.translatorscafe.com/unit-converter/en-US/frequency-wavelength/27-6/wavelength%20in%20metres-megahertz/
@@Simon_HDM YOU made a mistake! I NEVER said 1020 MHZ, I said 1.020 MHZ (1,020 Kilohertz), If you actually READ my post I called THAT out: "... if I am listening to KDKA-AM 1020 KHz in Pittsburgh.." You would have "caught" it.🤷♂️And THAT station is STILL on (after 102 years!!) at exactly 293.9141745098 METERS.
...and Simon left the chat.
Very nice explanation.
Це дуже добре
So .. 50 seconds in. Is that David Taylor research center in Annapolis Maryland??
Thinking back to my years in elementary school middle school high school if parents were given an option to choose a trade or specific skill they would like their child to possess throughout the years in school to kind of tagalong with their basic educations that wouldHave been helpful
That was a bad example of communication right at the end. Intelligible message? I couldn't tell what was being said.
He clearly said, "Wosh bosh moosh, im gwosh hosh bosh."
The audio is very choppy.
i called with PeriscopeFilm about the quality of videos and they generously announced that we must pay for better quality. I couldn't pay because our country banking systems was under sanction. I feel regretful. if we were in US in donate money for this Glorious Company
That's because the film broke and needed to be trimmed in order to be properly spliced back together. The audio appears on the edge of the 16mm film as a wavy line, which a photocell turns back into audio as it passes the detector. Sounds crude today, but pretty neat back then!
4:25 What happens at very very low frequencies?
ELF (extremely low frequency) is used to communicate with submarines.
Same thing...
@@flexairz So the wavefront seems to go backwards and meet up with the next one. That's a lot of time.
Noice
Westie mute 😐.
Higher frequency shorter wave length more towers...
"More towers" in what situation? Not sure what you're referring to, or how you reach that conclusion. Higher frequency signals are more easily aimed / focused by directional antennas, making them useful for point-to-point communications, provided that line-of-sight exists without obstacles between transmitting and receiving antennas.
@@gregm.857ok okay... perhaps l should say the more data in a signal the closer the towers need to be...that's my understanding from working in the industry..cheers
@@TheMinipeaThat's an interesting statement. I'd very much like to know the industry details that lead to that conclusion. I had never looked at it in quite that way. Maybe we should substitute "antenna" for "tower" since not all antennas are on actual towers. For example, consider XM radio, which has enough data for hundreds of audio channels. There are just a few transmitting antennas on the satellite (23,000 miles away) and for each listener just one receiving antenna (at their radio). Perhaps not the best example ... please help me understand the example you're familiar with.
Gas does not reflect radio waves in the ionosphere. The firmament is a self-regenerating ice/glass-like substance. There are 3 separate layers.
Light or any wave in the spectrum does not travel. It is a perturbation in the aether.
At last it all makes sense
🎖🎖🎖🎖🎖
HAARP
Electrical current is racist
Well of course it is. Everything is racist. Even you. You're racist. Hey racist...who do you hate based on race the most today?
If someone mentions racism, that person is a racist.
@@flexairz race doesn't exist.- science
@@flexairz Let that sink in for a moment.
😂