Types of Weather Radar Antenna
- The parabolic reflector form of weather radar antenna.satellite dish image by Freeze Frame Photography from Fotolia.com
Meteorologists obtain weather information by using various types of radar antennas. According to the National Weather Service, weather radar antennas emit energy that scatters once it hits objects like hailstones or raindrops. A small amount of that energy then bounces back to the radar system, and provides researchers with information about precipitation, weather intensity and location. - The symmetric parabolic reflector antenna uses a narrow beam to acquire a detailed scan of the atmosphere. The National Weather Service uses an advanced WSR-88 NEXRAD (Next Generation Radar) antenna to measure rainfall and wind. This antenna features an S-band parabolic dish with a center feed for accurate data acquisition. It is particularly good at detecting storms, and can endure severe weather conditions. It is also capable of scanning remote locations for meteorological phenomena.
- A phased array comprises two or more antennas that combine signals to obtain improved signal strength and performance. Where parabolic reflector antennas transmit a single beam of energy, phased arrays transmit multiple beams at once. The National Severe Storms Laboratory states that this technology can collect radar data in one-sixth of the time it takes a standard weather radar antenna. This helps to give researchers and forecasters advance warning of severe weather changes.
- Unlike a parabolic antenna, an omnidirectional broadcast antenna radiates energy in a 360-degree circle. This allows it to send radar pulses on a perpendicular plane without having to rotate. One drawback to using this type of antenna is that it can have limited vertical coverage below the antenna, depending on its positioning. According to the Antenna Engineering Handbook, the omnidirectional broadcast antenna is important for military applications and air traffic control.
- The quadrifilar helix (QFH) antenna can intercept and view images from the National Oceanic and Atmospheric Administration (NOAA) weather satellites that orbit Earth. The design of a QFH antenna is similar to that of a dipole antenna: Its tubular shape and looped helices allow it to receive vertical and horizontal signals. It is a relatively small antenna, and can be mounted on top of a roof or car. According to SkyCross, it is also usable as a personal satellite terminal.
