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Dayton Ohio USA 1947 stock footage and images
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Space research about the ionosphere from the ground by the National Bureau of Standards.
Film entitled 'Scatter Radar', from The National Bureau of Standards, United States Department of Commerce. Depicts space research from the ground. The globe rotating. A satellite antenna moves into position. Radio instruments. Red optical instruments used to study the sun. Clouds in the upper atmosphere. Animation: Ionosphere reflects radio waves to the planet. A smoke of cloud rises during the launching of a rocket. An artists' conception of the Van Allen Radiation Belt above the Earth's ionosphere discovered by Explorer I and Pioneer III. A satellite orbits the globe. Men watch as a rocket is erected and fired. A scientist at the National Bureau of Standards works on a formula. A man at the controls of a scatter radar fro space research. Animation: Ionized and neutral particles as well as free electrons that permit long distance communication. free electrons reflect radio energy. Radio waves penetrate the ionosphere. A scientist at the Ionosonde model C4 to measure electron density variations. Electron density model on the monitor. Two Oxygen atoms. An electron detaches and becomes a free electron. Radio waves pass by, the electron and waves oscillate and scatter energy. Animation: Need to excite electrons sufficiently so that their energy radiated can be detected from the ground. The process requires a powerful transmitter, large antenna, and a sensitive receiver.
Scatter Radar experimentation with Dr. Kenneth Bowles and his team, and their efforts in Lima Peru
Space research from the ground with a Scatter Radar. National Bureau of Standards laboratories in Boulder, Colorado. The Central Radio Propogation Laboratory. Cars parked outside. Hills in the background. Dr. Kenneth Bowles and a colleague work on a formula. Animation: Incoherent scatter of radio waves by electrons in the ionosphere. Transmission of powerful pulsed radio signal in a narrow beam. The beam penetrates the ionosphere and excites the free electrons. The scatter a weak signal which is detected by a sensitive antenna, and the signal comes back to Earth. Remaining portions of a sensitive antenna at the pioneering field site in Havana, Illinois. Dr. Ken Bowles and other scientists decide on a site. Animation: The magnetic equator and lines of the magnetic field. Pulsed radar signals and lines of force on the monitor. Animation: Chemical composition of the Earth's atmospheric gases. The scientists decide on Lima in Peru, due to its proximity to the magnetic equator and U.S. Lima, Peru: Buildings, guards, churches, plazas and boulevards in Lima including the Government Palace in Lima with guards in front, the Catedral de Lima (Catheral of Lima) and the Plaza Mayor de Lima . Construction work in Lima. Cars on a market street. People on the sidewalk. Shipping and port facilities in Callao, Peru. Workers unload goods. People board a Braniff International aircraft. Housing facility in the Lima suburb of Miraflores.
Communication waves and the relation between power transmitted and received in Space Communications
United States Air Force training film about Space Communications and the related problems and developments. Animation: Planets, remotely controlled unmanned space research vehicles in space. Space communication links between the vehicles and Earth. Radio waves are reflected, refracted and absorbed. An antenna radiates waves that are dispersed. Communication and light waves on the frequency spectrum. Groundwave and Skywave transmission explained. Skywave transmission reflected back to Earth by the ionized layers in the Earth's upper atmosphere. Bouncing of signal in optimal conditions. Spacewave travels from transmitting to receiving antenna, and travels unaffected through the ionosphere into outer planetary space. Depicts laws that govern Line of Sight transmission: Relation between power transmitted and power received, and ideal and regular conditions. Explains the factors involved in the relation between the power transmitted and received. Comparison of communication and light waves. Inverse Square Law explained. The law applied to Space Communication: Signal generated from point source, energy dispersed in shape of sphere, energy spreads over expanding spherical area. Outlines a practical approach to strengthen received power: Directing the radiating energy, and enlarging area of the receiving antenna.
Formula expressing relation between transmitted and received power and factors affecting Space Communications.
Space Communications and the related problems and developments. Animation: Final formula expressing the relation between power transmitted and power received. Comparison of the distance between Earth and the moon, and Earth and Pluto. Factors effecting Space Communication. Payload factor: Effect of payload weight of a communication equipment, transport of equipment, need for small and light equipment. Limitations in miniaturization of components: Inaccessibility in term of maintenance and service. Depicts longevity of power based on available power sources. Advantages and drawbacks of chemical batteries, solar batteries, nuclear batteries. States methods for reducing power consumption: equipping vehicles with command transponders. Factors effecting Sapce Communication: Spatial environment and equipment used. Example of information required to study the planet Venus: atmospheric composition, surface temperature changes and exact period of rotation. Explains spatial movement and solution for this factor: Placing four equally spaced terrestrial stations around the globe, joint by reliable communication links for continuity and data reception.
Transmission and reception of data, and frequencies and bandwidth considerations in Space Communications.
Space Communications and the related problems and developments. Animation: Additional factors introduces into Space Communications by transmission and reception of data. Frequencies and bandwidths applicable to Space Communications. Factors to be weighed while considering bandwidth: Available power and transmission system required. Narrower bandwidths used to conserve power, they're also less affected by noise interference. Depicts consumption of power by television, spoken word and teletype bandwidths. Telemetry: low bandwidth and power consumption. Explains Telemetry. Theory of Modern Communication and Binary digits or BITS. Depicts information required from outer space like: radio activity level of the moon's surface, abundance of water vapor in the Martian atmosphere, and variation in surface temperature of Mercury. Telemetry utilizes relatively small bandwidth and thus used as preferable mode of communication for research vehicles.
Use of video, and the various Orbiting and Satellite Systems in Space Communications.
Space Communications and the related problems and developments. Animation: Use of video for Space Communications requires highly directive antennas for power economy. Depicts enlargement of capture area of antennas located at terrestrial reception points. Efficiency in signal processing of the receiving equipment increased, to reduce intrinsic noise by reducing temperature of components. A satellite in Earth's orbit for space and terrestrial communications. Explains the Passive Sattelite Relay System using reflecting spheres; Single Orbiting Active Satellite System using line of sight communication, ideal for weather forecasting and mapping; and the sophisticated active Day Period Cry Satellite Orbiting System equipped with transponders.
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