الرادار وبعض الاجهزة الاخرى - الموجات اللاسلكية وعلم الفلك .. الإلكترونيات

Radar and some other devices - Radio waves and astronomy .. Electronics

Radar and some other devices

Radio waves propagate in a vacuum at a speed of 300,000,000 meters or 186,000 miles per second.

Therefore, if the signal frequency reaches 300,000,000 oscillations per second, its wavelength is one meter (234). It is known that electromagnetic waves consist of two electric and magnetic fields perpendicular to each other, and that they propagate in straight lines unless reflected by the Earth or the ionized layers around the Earth.

The reception of the antenna directed to the radio waves is good when it is directed towards the transmitting station. Accordingly, the optimal position of the antenna of the receiver is determined M in relation to the angular direction of the transmitting station (235 A). These directions intersect on the chart and the point of intersection is the optimal position for the receiver.

If the location of the transmitting station is unknown (235 B), we take directions from two different locations, and the point of intersection of the waves is the location of the transmitting station.

Radio waves and astronomy

Astronomical observations made directly using ordinary telescopes are limited to the range of visible frequencies. As for photographing dim stars, it depends on the exposure time of the film. It is known that fog absorbs visible rays and other similar radiations, while radiation with high frequencies, such as radio radiation, is characterized by waves longer than visible waves, and therefore it is difficult to prevent them from penetrating space.

234 - The speed of radio waves is 300,000,000 meters / second.

235 - Finding the direction of radio waves.

236 - Radio telescope.

237 - Visual observation and the results of radio astronomy.

In addition, distant galaxies and astronomical systems generate what is called "cosmic noise", which are random explosions that produce radio-frequency radiation that can be located using a directed antenna. It is also possible to use a plate-shaped reflector (236) that has a diameter of hundreds of feet and can focus the signals on the antenna itself. This reflector is characterized by being rotatable. As for the signals emitted from the locations of these radiations, they pass through sensitive devices where they are recorded. It is worth noting that the sources of radio noise are usually located near systems that can be seen using optical means (237). There is a map on which the locations of the sources of galactic noise are precisely identified, including noise sources that are located at great distances that no optical telescope can reach and are located in places where nothing can be seen or photographed. In this way, information was collected outside the scope of optical telescopes.