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In the classic educational film titled “Electronics at Work,” produced by Westinghouse in 1943, viewers are introduced to the fascinating world of vacuum tubes. This film highlights the crucial role these devices played in both military and commercial sectors, including radio telecommunications, radar, and various industrial applications. The narrative suggests that vacuum tubes provided the United States with a significant advantage during World War II, particularly in enhancing communication and technology.

The Continuing Relevance of Vacuum Tubes

Despite advances in technology, vacuum tubes remain in use today for several applications, including:

– Transmitting radios
– Medical devices
– Audio amplification systems
– High-frequency applications

Understanding Vacuum Tubes

The film outlines the six basic functions of electronic tubes and illustrates how each type is employed in different industrial and military contexts.

[embedyt] https://www.youtube.com/watch?v=ZJ6rN7WEjbc[/embedyt]

Structure of a Vacuum Tube

A vacuum tube typically consists of two or more electrodes housed within a vacuum inside an airtight enclosure. Key features include:

– Electrode Types: Most vacuum tubes have glass envelopes, although some utilize ceramic or metal casings with insulating bases.

– Leads and Sockets: The electrodes connect to leads that pass through the envelope via an airtight seal. These leads often take the form of pins, allowing for easy replacement in a tube socket, as tubes were a common point of failure in electronic devices.

– Capacitive Design: Some tubes feature a top cap on the electrode to minimize interelectrode capacitance, enhancing high-frequency performance and maintaining safety by separating high voltages.

The Evolution of Vacuum Tubes

The earliest vacuum tubes emerged from incandescent light bulbs, which contained a heated filament sealed in an evacuated glass envelope. When heated, the filament releases electrons into the vacuum through a process known as thermionic emission.

– Electrode Functionality: A second electrode, known as the anode or plate, attracts these electrons if it holds a more positive voltage. This mechanism results in a flow of electrons from the filament (cathode) to the plate, creating an electric field due to the potential difference between them.

– Diode Function: A vacuum tube with two electrodes is termed a diode, which functions as a rectifier. Diodes allow current to flow in only one direction, converting alternating current (AC) into pulsating direct current (DC). This technology is widely used in DC power supplies and in demodulating amplitude-modulated (AM) radio signals.

Film Availability and Production Details

This film is available in the public domain under Creative Commons, and it can be accessed through the Library of Congress Prelinger Archives. The film has been edited and converted to HD quality for better viewing. Introductory and closing music is provided by Nero 10, with commercial use rights granted.

This film not only serves as an educational tool but also highlights the enduring legacy of vacuum tube technology in the realm of electronics, illustrating its significant contributions to both past and present technological advancements.

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Great film about a great radio manufacturer and radio set.

In 1944, this short subject film was produced by the Jam Handy Organization and sponsored by the Hallicrafters Company. It shows the construction of the SCR-299 and dramatizes its use during World War II. This is a B&W documentary presenting a look at the manufacturing and use of the (now defunct) Hallicrafters Company’s SCR-299 “mobile communications unit.” This 1944 film, produced with help from the US Army Signal Corps, and by the Hallicrafters Company, explains how, using radio gear such as this Hallicrafters shortwave radio transmitter and receiver technology, the US Forces and Allies were better equipped to win World War II.

The SCR-299 “mobile communications unit” was developed to provide long-range communications during World War II. The US Military sought improvements of range, flexibility and durability over its existing SCR-197 and SCR-597 transmitters. In 1942, Hallicrafters Standard HT-4 was selected as the SCR-299’s transmitter, known subsequently by its military designation as the BC-610. The SCR-299 was first used on November 8, 1942, during Operation TORCH involving companies of the 829th Signal Service Battalion establishing a radio net that could exchange messages between beach-landed forces and bases in Gibraltar. Despite initial problems unloading the sets from convoy ships, the SCR-299s served until the installation of permanent Army Command and Administrative Network stations. According to US Army military historians, “General Dwight Eisenhower credited the SCR-299 in his successful reorganization of the American forces and final defeat of the Nazis at Kasserine Pass.”

The SCR-299 was a “self-contained” receiving and transmitting mobile high-frequency (HF; or, shortwave) station capable of operating from 2 MHz to 8 MHz. Using conversion kits, it could operate from 1 MHz to 18 MHz. The transmitter output reached 350 watts.

The entire unit came in a K-51 truck except for Power Unit PE-95 which was in a K-52 trailer. Power could either be supplied by the Power Unit and a 12-volt storage battery or 115-volt 60-cycle AC commercial power and two spare 6-volt storage batteries. The power requirement was 2000 watts, plus 1500 watts for heater and lights.

The system could be remotely controlled up to a distance of one mile (1.6 km) using two EE-8 field telephones and W-110-B Wire kit. Remote equipment was provided for remotely keying or voice modulating the transmitter, remotely listening to the receiver, and for communicating with the operator of the station.

Read more details here: http://en.wikipedia.org/wiki/SCR-299

Public domain film from the Library of Congress Prelinger Archive.

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73 de NW7US

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This old WWII military training video is still useful regarding Morse code:

[embedyt]https://www.youtube.com/watch?v=YqTn-165orw[/embedyt]

This is an antique United States Navy Training Film from 1943/1944, in which proper hand-sending of Morse code is demonstrated. The film covers some basic principles and mechanics of manual keying of the International Morse code, as used during WWII.

Amateur (Ham) radio operators find Morse code (and the ‘CW’ mode, or ‘Continuous Wave’ keying mode) very useful, even though Morse code is no longer required as part of the licensing process. Morse code is highly effective in weak-signal radio work. And, preppers love Morse code because it is the most efficient way to communicate when there is a major disaster that could wipe out the communications infrastructure.

While this military film is antique, the vintage information is timeless, as the material is applicable to Morse code, even today.

There’s more about Morse code, at my website: http://cw.hfradio.org

For additional joy, here are a few of old films regarding Morse code:

Morse Code – Principles and Basic Techniques (US Army Signal)
(Learn to Send Perfect Morse Code by Hand – Vintage Training Film (Ham Radio / CW))
[embedyt]https://www.youtube.com/watch?v=qmg1MlstxWM[/embedyt]

Vintage 1944 Radio Operator Training: How to Send Morse Code (CW) by Hand
[embedyt]https://www.youtube.com/watch?v=XjupJslRj5E[/embedyt]

This one is a pretty cool film:
1939 Film: New Zealand Shortwave Communications; Morse code (CW)
[embedyt]https://www.youtube.com/watch?v=H-KUat5WEkU[/embedyt]

I’ve also created a play list, and most of the videos are still online. Once and a while something changes and I have to update the list. Here is the list:

CW Play List

Original Title: TECHNIQUE OF HAND SENDING, by Department of Defense, Published 1944

Usage CC0 1.0 Universal

TECHNIQUE OF HAND SENDING
PIN 23735 1944

IMPORTANT PARTS OF THE TRANSMITTER, TENSION SPRING, ADJUSTING CONTACTS, ADJUSTING SPRINGS. ELEMENTS OF MORSE CODE, TIMING, AND PARTS OF BODY THAT FUNCTION WHEN TRANSMITTING CODE. IMPORTANCE OF CORRECT POSITION AND OPERATION.

Producer Department of Defense

Enjoy!

“Radio Hams” do more than play with their machines. They are also invaluable in relaying vital information during times of tragedy and disaster.

Here is a mildly entertaining look at radio hams, those amateurs sending and receiving coded messages during the late thirties when films first dealt with the subject of “radio hams.” In this case, the ham operators manage to be helpful during situations of stress, using their abilities with code to help someone in distress and to seek aid for pilots flying a missing plane.

The humorous ending has the family gathered around the radio listening to someone speaking Chinese while the narrator tells us how impressed the family was to be hearing someone across the world on their radio set.

http://www.youtube.com/watch?v=bZi7LiPNMt8

This little vintage film, a rather more serious film than many of Pete Smith’s other presentations, takes a look at how ham radios can become priceless aids during emergencies. The two stories shown, one dealing with sickness, the other with a missing plane, are bookended by a humorous look at a typical three-generation family’s fascination with their ham radio.

Of course, amateur radio, or “ham radio”, is alive and doing very well, in our modern times. Using satellites, moon-bounce communications, repeater networks, as well as shortwave, mediumwave, and longwave telecommunications technology, amateur radio continues to provide emergency services in times of need, from hurricanes, tornadoes, earthquakes, and even during such times as the infamous 9/11 atrocity. But, amateur radio also breeds invention and experimentation, always at the cutting edge of science. It is a hobby worth investigating, having room for a wide-range of interests. Preppers, science lovers, experimenters, and those with a passion to meet people from all over the world by way of radio waves, all together make up the radio hobby of amateur radio.

Clayton Moore, later famous as the Lone Ranger, appears uncredited as a ship radio operator.

Directed by Felix E. Feist

Writing Credits Buddy Adler (screenplay) (as E. Maurice Adler)

Cast (in alphabetical order)

Barbara Bedford – Mrs. Crane (uncredited)
Eleanor Counts – Miss Mulligan, Jimmy’s Sister (uncredited)
Jack Daley – Pa Mulligan (uncredited)
Robert Homans – Lighthouse Keeper (uncredited)
Clayton Moore – Ship Radio Operator (uncredited)
Alonzo Price – Clyde DeVinna (uncredited)
Jason Robards Sr. – Pilot in Distress (uncredited)
Pete Smith – Narrator (voice) (uncredited)
Harry Strang – Man in Montage (uncredited)
Phillip Terry – Co-Pilot (uncredited)
Dorothy Vaughan – Ma Mulligan (uncredited)

Produced by Pete Smith – producer (uncredited)
Music by David Snell (uncredited)
Cinematography by Robert Pittack
Film Editing by Philip W. Anderson (as Philip Anderson)
Music Department Jack Virgil – orchestrator (uncredited)
Other crew Douglas Smith – technical advisor

According to https://archive.org/details/wwIIarchive this film is in the Public Domain.
Creative Commons copyright.

This is for you vintage science film buffs: here is a circa 1920 film: How the Telephone Talks (A Silent Film).

This is an educational film from 1920 that explained the “modern” telephone. The concepts are still relevant to today’s modern versions, including the cell phone, which is both radio and telephone.

From Wiki:

A telephone, or phone, is a telecommunications device that permits two or more users to conduct a conversation when they are not in the same vicinity of each other to be heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals suitable for transmission via cables or other transmission media over long distances, and replays such signals simultaneously in audible form to its user. The word telephone has been adapted into the vocabulary of many languages. It is derived from the Greek: τῆλε, tēle, far and φωνή, phōnē, voice, together meaning distant voice.

First patented in 1876 by Alexander Graham Bell and further developed by many others, the telephone was the first device in history that enabled people to talk directly with each other across large distances. Telephones became rapidly indispensable to businesses, government, and households, and are today some of the most widely used small appliances.

The essential elements of a telephone are a microphone (transmitter) to speak into and an earphone (receiver) which reproduces the voice of the distant person. In addition, most telephones contain a ringer which produces a sound to announce an incoming telephone call, and a dial used to enter a telephone number when initiating a call to another telephone. Until approximately the 1970s most telephones used a rotary dial, which was superseded by the modern Touch-Tone push-button dial, first introduced by AT&T in 1963. The receiver and transmitter are usually built into a handset which is held up to the ear and mouth during conversation. The dial may be located either on the handset, or on a base unit to which the handset is connected by a cord containing wires. The transmitter converts the sound waves to electrical signals which are sent through the telephone network to the receiving phone. The receiving telephone converts the signals into audible sound in the receiver, or sometimes a loudspeaker. Telephones are a duplex communications medium, meaning they allow the people on both ends to talk simultaneously.

A landline telephone is connected by a pair of wires to the telephone network, while a mobile phone, such as a cellular phone, is portable and communicates with the telephone network by radio transmissions. A cordless telephone has a portable handset which communicates by radio transmission with the handset base station which is connected by wire to the telephone network.

The telephone network, consisting of a worldwide net of telephone lines, fiber optic cables, microwave transmission, cellular networks, communications satellites, and undersea telephone cables connected by switching centers, allows any telephone in the world to communicate with any other. Each telephone line has an identifying number called its telephone number. To initiate a telephone call the user enters the other telephone’s number into a numeric keypad on the phone.

Although originally designed for simple voice communications, most modern telephones have many additional capabilities. They may be able to record spoken messages, send and receive text messages, take and display photographs or video, play music, and surf the Internet. A current trend is phones that integrate all mobile communication and computing needs; these are called smartphones.

( http://g.nw7us.us/1996vSl )