Search results
Results from the WOW.Com Content Network
Powerline worker performs maintenance of a lightning arrester on an electrical transmission tower in New Brunswick, Canada. A lightning arrester (alternative spelling lightning arrestor) (also called lightning isolator) is a device, essentially an air gap between an electric wire and ground, used on electric power transmission and telecommunication systems to protect the insulation and ...
A lightning protection system includes a network of air terminals, bonding conductors, and ground electrodes designed to provide a low impedance path to ground for potential strikes. Lightning protection systems are used to prevent lightning strike damage to structures. Lightning protection systems mitigate the fire hazard which lightning ...
A Perry Weather lightning warning system. The detection equipment is designed to constantly survey atmospheric electrical activity and potential for lightning occurrence via radar and other methods. [citation needed] Storms are scanned by radar to determine the degree of electrification and potential for lightning occurrence. [citation needed]
A lightning detector is a device that detects lightning produced by thunderstorms. There are three primary types of detectors: ground-based systems using multiple antennas, mobile systems using a direction and a sense antenna in the same location (often aboard an aircraft), and space-based systems.
Counterpoises are typically used in antenna systems for radio transmitters where a good earth ground connection cannot be constructed.. Monopole antennas used at low frequencies, below 3 MHz, such as the mast radiator antennas used for AM broadcasting, require the radio transmitter to be electrically connected to the Earth under the antenna; this is called a ground (or earth).
The AN/APG-81 is an active electronically scanned array (AESA) fire-control radar system designed by Northrop Grumman Electronic Systems (formerly Westinghouse Electronic Systems) for the Lockheed Martin F-35 Lightning II. [1] The AN/APG-81 is a successor radar to the F-22's AN/APG-77, and has an antenna composed of 1,676 transmit/receive modules.
In electromagnetics and antenna theory, the aperture of an antenna is defined as "A surface, near or on an antenna, on which it is convenient to make assumptions regarding the field values for the purpose of computing fields at external points. The aperture is often taken as that portion of a plane surface near the antenna, perpendicular to the ...
This feedline system design has the advantage of reducing the retuning required when the operating frequency is changed. A similar design can match an antenna to a transmission line; For example, many TV antennas have a 300 Ohm impedance and feed the signal to the TV via a 75 Ohm coaxial line. A small ferrite core transformer makes the broad ...