Posts tagged Development of Radio
BBC Television Received in New York - November 1938

Science & Technology History

BBC Television in New York

“November [1938] - Due to freak atmospheric conditions, a BBC TV broadcast is received in New York City. A film camera is used to record the silent images which included the performance of a play, a cartoon, and other matter. A four-minute excerpt from this filmed recording survives and is, as of 2014, considered the only surviving example of a pre-war BBC television transmission.” • Wikipedia

“The four-minute compilation from 1938 exists only because of a technological fluke and the enthusiasm of two television buffs, one in Britain and the other in America where, thanks to freak atmospheric conditions, it was picked up and recorded on a cine camera placed in front of a television screen as the images came in.

Andrew Emmerson, the British enthusiast, spent five years tracking down the recording and believes it is the only surviving example of pre-war live high-definition British television. The flickering black-and-white footage includes Jasmine Bligh, one of the original BBC announcers, and a brief shot of Elizabeth Cowell, who also shared announcing duties with Jasmine, an excerpt from an unknown period costume drama and the BBC's station identity transmitted at the beginning and end of the day's output.” • Archive.org

1938- BBC Broadcast Seen In New York – “The following is the only off air pre World War II BBC recording to currently exist. This was caused by bizarre weather conditions, which somehow made a BBC broadcast visible in New York.”

“Broadcasts from the BBC Television Station at Alexandra Palace travelled less than 30 miles, but because of the sun spots they were being bounced off the ionosphere and picked up 3,000 miles away on the East Coast of America."

“It was made at a time when no technology existed to record live broadcasts directly. Video tape was not perfected until the late 1950s and "telerecording", the quality copying with a cine camera mounted in front of a television screen was not developed until after the Second World War. There are other recordings from the pre-war era, but they are all cine film shot from a camera alongside the television lens, or as in the case of the Demonstration Films, recreated scenes in a shot in a film studio. 

The American recording was shown on 26 June 1999 at the refurbished National Museum of Photography, Film and Television in Bradford.

Mr Emmerson, 50, a freelance researcher and writer on the television industry, said: "Rumours of a recording existing in America have circulated for years, but no one had ever got to the bottom of them. It was known that about this time there had been tremendous sun spot activity, which had a dramatic effect on the ionosphere. Broadcasts from the BBC Television Station at Alexandra Palace travelled less than 30 miles, but because of the sun spots they were being bounced off the ionosphere and picked up 3,000 miles away on the East Coast of America."

"There were reports that RCA, which was working on its own television system, had conducted an experiment to film the broadcasts. About five years ago I decided to check it out, but with no success. RCA could not trace anything, nor could anyone else. Then last year a friend at the American Vintage Wireless Collectors' Society agreed to mention it in their magazine."

One of the respondents was Maurice Schecheter, who worked in a New York television studio. He had a collection of television material and among it was one of the RCA recordings on 16mm film. a television screen as the images came in.

"He cleaned it up digitally and transferred it to a video cassette for me," Mr Emmerson said. "I was astounded. This was the oldest and probably the only example of live high-definition television from the pre-war period."

This film footage is from the Archive Collection held and administered by the Alexandra Palace Television Society.“ • Archive.org

Alexandra Palace Television Society home page

Skywave or skip hf / shortwave propagation. Image altered. • Wikimedia Commons

Skywave or skip hf / shortwave propagation. Image altered. • Wikimedia Commons

The Skywave: Skipping Waves of Electricity in 1938

"In radio communication, skywave or skip refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere. Since it is not limited by the curvature of the Earth, skywave propagation can be used to communicate beyond the horizon, at intercontinental distances. It is mostly used in the shortwave frequency bands.

As a result of skywave propagation, a signal from a distant AM broadcasting station, a shortwave station, or – during sporadic E propagation conditions (principally during the summer months in both hemispheres) a distant VHF FM or TV station – can sometimes be received as clearly as local stations. Most long-distance shortwave (high frequency) radio communication – between 3 and 30 MHz – is a result of skywave propagation. Since the early 1920s amateur radio operators (or "hams"), limited to lower transmitter power than broadcast stations, have taken advantage of skywave for long distance (or "DX") communication." • Wikipedia

The Ionosphere and The Heaviside Layer

"The ionosphere is the ionized part of Earth's upper atmosphere, from about 60 km (37 mi) to 1,000 km (620 mi) altitude, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth." • Wikipedia

“The Heaviside layer, sometimes called the Kennelly–Heaviside layer, named after Arthur E. Kennelly and Oliver Heaviside, is a layer of ionised gas occurring between roughly 90 and 150 km (56 and 93 mi) above the ground — one of several layers in the Earth's ionosphere. It is also known as the E region. It reflects medium-frequency radio waves. Because of this reflective layer, radio waves radiated into the sky can return to Earth beyond the horizon. This "skywave" or "skip" propagation technique has been used since the 1920s for radio communication at long distances, up to transcontinental distances. Propagation is affected by time of day. During the daytime the solar wind presses this layer closer to the Earth, thereby limiting how far it can reflect radio waves.

Conversely, on the night (lee) side of the Earth, the solar wind drags the ionosphere further away, thereby greatly increasing the range which radio waves can travel by reflection. The extent of the effect is further influenced by the season, and the amount of sunspot activity.” • Wikipedia

Almost 30 Years Later: Our World

“Our World was the first live, international, satellite television production, which was broadcast on 25 June 1967. Creative artists, including the Beatles, opera singer Maria Callas, and painter Pablo Picasso – representing nineteen nations – were invited to perform or appear in separate segments featuring their respective countries. The two-and-a-half-hour event had the largest television audience ever up to that date: an estimated 400 to 700 million people around the globe watched the broadcast.

Today, it is most famous for the segment from the United Kingdom starring the Beatles. They performed their song "All You Need Is Love" for the first time to close the broadcast.

The project was conceived by BBC producer Aubrey Singer. It was transferred to the European Broadcasting Union, but the master control room for the broadcast was still at the BBC in London. The satellites used were Intelsat I (known as "Early Bird"), Intelsat 2-2 ("Lani Bird"), Intelsat 2–3 ("Canary Bird"), and NASA's ATS-1.

It took ten months to bring everything together. The Eastern Bloc countries, headed by the Soviet Union, pulled out four days before the broadcast in protest of the Western nations' response to the Six-Day War.

The ground rules included that no politicians or heads of state could participate in the broadcast. In addition, everything had to be "live", so no use of videotape or film was permitted. Ten thousand technicians, producers and interpreters took part in the broadcast. Each country had its own announcers, due to language issues, and interpreters voiced over the original sound when not in a country's native language.

Fourteen countries participated in the production, which was transmitted to 24 countries, with an estimated audience of between 400 and 700 million people.” • Wikimedia Commons

"Love Is All You Need"

All You Need Is Love - Our World 1967

Our World Global Satellite Broadcast

“Our World was the first live, world-wide satellite programme - broadcast on the 25th June 1967 (7.55pm to 10.00pm) to an international audience in excess of 350 million. The programme was divided into sections with people contributing from all over. The Beatles performed "All You Need Is Love", which was broadcast from a crowded Studio Two at Abbey Road Studios. The band had invited many friends, including The Rolling Stones, Eric Clapton and Marianne Faithfull to join in the chorus and add to the atmosphere.” • The Beatles.com


Our World Today: HAARP

“The ionosphere starts at about 60 to 80 km altitude and extends up above 500 km altitude.  There are free electrons and ions in the ionosphere that radio waves can interact with. HAARP radio waves heat the electrons and create small perturbations that are similar to the kinds of interactions that happen in nature. Natural phenomena are random and are often difficult to observe. With HAARP, scientists can control when and where the perturbations occur so they can measure their effects.  In addition, they can repeat experiments to confirm the measurements really show what researchers think they do.“

University of Alaska Fairbanks – Geophysical Institute – FAQ – What is HAARP Used For?

“With a facility like HAARP, it is possible to perform an experiment at will to create plasma structures and irregularities, use the ionosphere like an antenna to excite low frequency waves, create weak luminous aurora-like glows and a variety of other experiments.”

University of Alaska Fairbanks – Geophysical Institute – FAQ –How Does HAARP Work?


LEARN MORE:

A Highly Reflecting Microwave Plasma Mirror

Reflection of microwave through laboratory plasma

Long-Distance Transfer of Microwaves in Plasma Waveguides

Famous Scientific Illusions by Nikola Tesla

Plasma Antennas and Microwaves

History of Cosmic Microwave Background Radiation

Discovery of Cosmic Microwave Background Radiation

Holmdel Horn Antenna

NASA – Goddard Media Studios: Welcome to the Ionosphere

ENCYCLOPÆDIA BRITANNICA: Ionosphere and Magnetosphere

ENCYCLOPÆDIA BRITANNICA: Radio Waves

Electromagnetic waveS

PBS: Who Invented Radio? 

TESLA INVENTED RADIO, NOT MARCONI!

The Inventions Researches and Writing of Nikola Tesla: Experiments with Alternate Currents of Very High Frequency

High-Frequency Active Auroral Research Program (HAARP)

Magnetosphere ChronologyNASA Educational Website on the TerrellaPlasma Physics

The US military is testing stratospheric balloons that ride the wind so they never have to come down

Edward V. Appleton. •. Kennelly-Heaviside Layer • SkywaveEarth–Moon–Earth Communication

Sporadic E PropagationMicrowave Transmission

“The Es layer (sporadic E-layer) is characterized by small, thin clouds of intense ionization, which can support reflection of radio waves, rarely up to 450 MHz. Sporadic-E events may last for just a few minutes to several hours. Sporadic E propagation makes VHF-operating radio amateurs very excited, as propagation paths that are generally unreachable can open up. There are multiple causes of sporadic-E that are still being pursued by researchers. This propagation occurs most frequently during the summer months when high signal levels may be reached. The skip distances are generally around 1,640 km (1,020 mi). Distances for one hop propagation can be anywhere from 900 km (560 mi) to 2,500 km (1,600 mi). Double-hop reception over 3,500 km (2,200 mi) is possible.” • Wikipedia

"The F region of the ionosphere is home to the F layer of ionization, also called the Appleton–Barnett layer, after the English physicist Edward Appleton and New Zealand physicist and meteorologist Miles Barnett. As with other ionospheric sectors, 'layer' implies a concentration of plasma, while 'region' is the volume that contains the said layer. The F region contains ionized gases at a height of around 150–800 km (100 to 500 miles) above sea level, placing it in the Earth's thermosphere, a hot region in the upper atmosphere, and also in the heterosphere, where chemical composition varies with height. Generally speaking, the F region has the highest concentration of free electrons and ions anywhere in the atmosphere. It may be thought of as comprising two layers, the F1 and F2 layers.” • Wikipedia

ThermosphereInternational Space Station OrbitGeostationary Orbit

“The F-region is located directly above the E region (formerly the Kennelly-Heaviside layer) and below the protonosphere. It acts as a dependable reflector of HF radio signals as it is not affected by atmospheric conditions, although its ionic composition varies with the sunspot cycle. It reflects normal-incident frequencies at or below the critical frequency (approximately 10 MHz) and partially absorbs waves of higher frequency."

“Under rare atmospheric conditions, F2 propagation can occur, resulting in VHF television and FM radio signals being received over great distances, well beyond the normal 40–100 miles (64–161 km) reception area.” • Wikipedia

“…This regular fluctuation is caused by electrical currents high in the ionosphere, a region above about 100 km altitude. All currents, like those in wires, can only flow in materials that conduct. The copper used in wires conducts very well but the air is a poor conductor. However, in the ionosphere high energy ultra-violet rays and X-rays from the Sun displace electrons from (or ionise) the neutral (uncharged) molecules in the air to produce positive and negatively charged particles (see Figure 14, '+' and '-' represent the charged particles). These charges allow the air to conduct. At any point on Earth, the Sun is at its most intense around midday and is therefore generating the most charges in the ionosphere overhead, which allows the air to conduct better. After dusk, in the absence of ionising radiation, the charges begin to recombine into neutral molecules again and so the ability for the air to conduct is reduced. This cycle is repeated each day.” • British Geological Survey

“Cosmic rays attract great interest practically, due to the damage they inflict on microelectronics and life outside the protection of an atmosphere and magnetic field, and scientifically, because the energies of the most energetic ultra-high-energy cosmic rays (UHECRs) have been observed to approach 3 × 1020 eV, about 40 million times the energy of particles accelerated by the Large Hadron Collider. One can show that such enormous energies might be achieved by means of the centrifugal mechanism of acceleration in active galactic nuclei. At 50 J, the highest-energy ultra-high-energy cosmic rays (such as the Oh-My-God particle recorded in 1991) have energies comparable to the kinetic energy of a 90-kilometre-per-hour (56 mph) baseball. As a result of these discoveries, there has been interest in investigating cosmic rays of even greater energies. Most cosmic rays, however, do not have such extreme energies; the energy distribution of cosmic rays peaks on 0.3 gigaelectronvolts (4.8×10−11 J).” • Wikipedia

A klystron is a specialized linear-beam vacuum tube, invented in 1937 by American electrical engineers Russel and Sigurd Varian, which is used as an amplifier for high frequencies, from UHF radio frequencies up into the microwave range. Low-power klystrons are used as local oscillators in superheterodyne radar receivers, while high-power klystrons are used as output tubes in UHF television transmitters, microwave relay, satellite communication, and radar transmitters, and to generate the drive power for modern particle accelerators.

… Klystrons can produce far higher microwave power outputs than solid state microwave devices such as Gunn diodes. In modern systems, they are used from UHF (hundreds of MHz) up through hundreds of gigahertz (as in the Extended Interaction Klystrons in the CloudSat satellite). Klystrons can be found at work in radar, satellite and wideband high-power communication (very common in television broadcasting and EHF satellite terminals), medicine (radiation oncology), and high-energy physics (particle accelerators and experimental reactors). At SLAC, for example, klystrons are routinely employed which have outputs in the range of 50 megawatts (pulse) and 50 kilowatts (time-averaged) at 2856MHz.“ • The University of Arizona Physics Department