A satellite phone is a mobile telephone which communicates using satellites instead of using cell towers.
Three major satellite phone networks are currently in operation:
Iridium
Globalstar
Thuraya
Iridium
The Iridium network uses 66 low earth orbit satellites in polar orbits 485 miles above sea level.
The use of low earth orbit satellites helps minimize round-trip-time, which greatly improves the perceived quality of the phone call.
The Iridum network is able to provi
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The basic types of satellite systems include geostationary (GEO), Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Highly Elliptical Orbit (HEO) satellites. There are also public and private satellite systems such as Television Receive Only (TVRO), Direct Broadcast Satellite (DBS), Global Positioning System (GPS), and multibeam satellite operations.
Geosynchronous satellites orbit the Earth on repeatedly regular points over time. Each GEO satellite is stationary over one spot above the eq
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Rainfade refers to a phenomenon that occurs during strong rain or snowfall in which satellite signals are prevented from reaching their destination. Rainfade may also refer to extensive cloud cover, strong winds, or any other environmental effect that distorts a satellite broadcast, but is most often observed during rainfall. Rainfade may also refer to the slow speeds of WiFi and other wireless data transmissions during storms or other undesirable weather conditions that are caused by the sa
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Inclination is the angle between a satellite orbit and the equator.
Inclination is measured as the angle at which the satellite crosses the equator while passing from the southern hemisphere to the northern hemisphere.
A satellite travelling in a geostationary obit will have an inclination of zero.
Inclination is between 0 and 90 degrees for satellites in non-retrograde orbits, and between 90 and 180 degrees for satellites in retrograde orbits.
A satellite in a polar orbit will have
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An amplifier uses a small input signal to create a large output signal, while minimizing distortion of the waveform. Amplifiers are used for both electrical and optical signals.
Working of an Amplifier
Modern amplifiers use solid-state electronics, although some are still made with vacuum tubes. A basic amplifier can be made with transistors, while complex amplifiers use other components, like op-amps, for feedback correction. To reduce the electrical noise, most amplifiers use toroidal tran
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A diode is a solid-state device that allows current to flow in only one direction, a process known as rectification. Diodes are a fundamental component of electrical circuits. They are also used to form other components, such as the bipolar transistor which uses two diodes in series.
History of the Diode
Thermionic rectifiers were discovered in 1873 by Frederick Guthrie, and later rediscovered by Thomas Edison in 1880, while crystal rectifiers were discovered in 1874 by Karl Braun. It wasn
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An ultrasonic sensor is a device that works in much the same way as RADAR and SONAR. In fact, ultrasonic sensors mimic bats and other animals' natural ability to use ultrasonic frequencies for navigation. Ultrasonic sensors broadcast a powerful, ultrasonic frequency, then detect the ultrasonic sound waves as they bounce off of objects and return to the sensor. They are almost always used to measure speed or direction and are very efficient at determining position.
How Ultrasonic Sensors Work
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The term wire gauge refers to a measurement of what the diameter of a wire is. This measure can then be used to determine what the electrical resistance, weight per unit of length, and the amount of current that can safely be carried by the wire. There are two internationally accepted measures for wire gauge, the Metric Wire Gauge (MWG) and American Wire Gauge (AWG) standards.
American Wire Gauge (AWG)
The standardized gauge system used for wire measurement in the United States and Canada is t
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Radio-Frequency Identifier (RFID) technology has become really popular because of the various advantages it comes with. However, such as passports, national identity cards, credit cards etc have become a serious security concern. Two electrical engineering students (Ilan Kirschenbaum and Avishai Wool) from Tel Aviv University wrote a paper titled "How to Build a Low-Cost, Extended-Range RFID Skimmer." The paper demonstrates just how very simple it has become to 'skim'
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An integrated circuit (IC), also called a microchip, is an electronic circuit etched onto a silicon chip. Their main advantages are low cost, low power, high performance, and very small size.
History
The integrated circuit was invented in 1958 by Jack Kirby (1923-2005), an American engineer. In 2000, he won the Nobel prize in physics for his integrated circuit. This basic design has evolved over the last half century to reach the level of the modern computer chip, which has millions of transis
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