Some impotent tips to create different symbols through your computer Keyboard with a combination of Alt and Numbers from 0 to 9 Alt + 1 = ☺ Alt + 2 = ☻ Alt + 3 = ♥ Alt + 4 = ♦ Alt + 5 = ♣ Alt + 6 = ♠ Alt + 7 = • Alt + 8 = ◘ Alt + 9 = ○ Alt + 10 = ◙ Alt + 11 = ♂…"Creat Symbols through your Keyboard"
JET_TECHNODHUNIAH Airplane engines may be classified as driven by propeller, Jet, Turbojet, and Rocket. Most engines originally were of the internal-combustion, piston-operated type, which may be air-or liquidcooled. PROPELLER_TECHNODHUNIAH During and after world war II, duct-type and gas-turbine engines became increasingly important, and since then jet TURBOJET_TECHNODHUNIAH propulsion has became the main form of power in most commercial and military aircraft. The landing gear is the understructure that supports the weight of the craft when…"Airplane :: Classification of Airplane"
A communication satellite is, in fact, a microwave transmitter/receiver, known as earth stations, or ground stations. The satellite receives transmission on one frequency band(uplink), amplifies or repeat the signal, and transmit it on another frequency (downlink). A single orbiting satellite will operate on a number of frequency bands, called transponder channels, or simply transponders. Thus, the satellites are transponders that are set in geostationary orbits directly over the equator. These geostationary orbits are 36000 km…"Wireless Transmission and Satellite Microwaves."
Microwaves use line of sight propagation. Microwaves frequency ranges from 1 to 300 GHz. Microwaves are used in cellular phones, satellite networks and wireless LANs. Microwaves are unidirectional. It is useful in unicasting i.e. one to one communication. To travel longer distances, the antennas must be taller. There should not be any obstacle in between. Usually mountain tops are the preferred positions for the antennas to avoid obstacles. Microwave can travel for one direction at…"Wireless Transmission and Microwaves."
Infrared signals used for short range communication. It has the frequency range from 300 GHz to 400 THz. It has wavelength from 1 mm to 770 mm. Infrared communications is achieved by using the transmitters/ receivers that modulate infrared light. Transceivers must be within the line of sight of each other directly or via reflection. One disadvantage of infrared is that is dose not penetrate walls. We can not use infrared outside a building because…"Wireless Transmission and Infrared Waves."
The radio waves are omnidirectional. While the microwaves are directional. Radio waves are used for one sender and multiple receivers i.e. for multicusting property. Because of this multicast communication, it is used by radio, television, cordless phones and pagers. Radio waves is a general term to encompass frequencies in the range 3 KHz to 1 GHz. The microwaves ranges in frequencies between 1 to 300 GHz. Broadcast radio term may be informally used for the…"Wireless Transmission and Radio Waves."
For wireless communication, signals can travel from source to destination in several ways they are ground propagation, sky propagation and line-of-sight propagation. GROUND PROPAGATION: Radio waves travel through the lowest portion of the atmosphere. These low frequency signal emanate in all directions from the transmitting antenna and follow the curvature of the planet. Distance depends on the amount of power in the signal. This type of propagation is called Ground Propagation. SKY PROPAGATION: Higher frequency…"Wireless Transmission of Netwrok."
The part of electromagnetic spectrum, defined as radio and microwaves, can be further divided into eight ranges, called bands. These bands are rated from very low frequency (VLF) to Extremely High frequency (EHF) Very Low Frequency :: These waves propagate as surface waves, usually through air, sometimes through water. VLF may be affected by atmospheric noise. VLF waves are usually used for long range radio navigation and submarine communication. Low Frequency :: these waves propagate…"The Parts of Electromagnetic Spectrum."
Light actually originates from the accelerated motion of electrons of atom. Atoms emit light in tiny packets of energy called photons. Photons move through space as electromagnetic waves, which are a form of energy with magnetic and electrical components. The electromagnetic waves travels at the same speed of light (c) through vacuum, no matter what their frequency the number of oscillations per second of a wave is called its frequency, f, and is measured in…"Electromagnetic Spectrum, Unguided Media of Transmission."
Fiber optic cable is now extensively used as a communication medium for backbone networks due to its low cost wide bandwidth. Its data transfer rate now arrived at 1600 Gbps. Some cable TV companies used a combination of optical fiber and coaxial cable. Here optical fiber provides the backbone network and the coaxial cable gives service connection to the users. 100Base-FX and 1000Base-X LAN uses optical fiber cable.…"Applications, Advantages and Disadvantages of Fiber Optic Cable."