Instant Doppler 6 was constructed at the WRGB-CBS6 facility at 1400 Balltown Road in Niskayuna, NY the last week in November 2000 marking the culmination of two years of research and planning which began during the summer of 1998. Zoning for the radar tower was granted by the town of Niskayuna in July 2000, with the proviso that an existing tower on the roof of the building be removed with that tower's telecommunications equipment relocated to the new Doppler tower within one year of project competition. WRGB purchased both the tower and the radar system in August 2000.
Tower construction began in October of 2000 with the pouring of three huge concrete pilings which each extend into the ground to a depth of twenty four feet giving the structure significant stability and a wind tolerance to 85 mph.
The tower itself was delivered to WRGB the week of November 23rd and came in approximately 750 separate segments which had to be lifted into place and bolted one segment at a time. Tower construction and radar assembly spanned approximately eight days with the radarsystem itself being lifted into place by a 175 foot crane on Tuesday, November 28, 2000, becoming the first live Doppler radar installed at a television station in the Albany, Schenectady, Troy market.
Instant Doppler 6 Statistics & Capabilities
The Instant Doppler 6 tower and radar assembly rise to a height of 150 feet, towering over the WRGB facility. Economic as well as meteorological concerns were factored into determining the ultimate height of the tower. The 150 foot elevation provides the radar with sufficient clearance of trees, buildings, and terrain, allowing it to fully scan area weather. The radar itself is located in a spherical radome ten feet in diameter at the very top of the tower. The radome's purpose is to protect the radar components from the elements. Included within the radome are the radar receiver/transmitter (R/T), the radar pedestal, and the 8' parabolic high gain antenna. The reliever/transmitter is the component that generates the radar's microwave signal, at a C band operating frequency of 5.44 GHz. The antenna focuses and directs the beam (1.75 degree maximum beam width) out from the unit and also receives the returned signal which is then processed by the receiver/transmitter and converted into the standard display shown on the air. The antenna is attached to the pedestal which is the hardware that allows the system to rotate horizontally both in a clockwise as well as counterclockwise direction and tilt vertically. The control module for the radar is located in the Channel 6 weather office.
The radar has a range of sensitivity settings, much like the National Weather Service NEXRAD system, allowing the radar to detect very light snow or flurry activity to the most intense thunderstorm. The system has three rotation speeds, 0.9375 rpm, 1.875 rpm, and 3.75 rpm. Typically, to reduce pedestal wear, the radar will operate at the lowest rotation speed. However, during fast moving severe weather events, the rotation speed is pushed to the maximum. The 360 degree antenna rotation may be stopped to confine the sweep to a sector scan. The purpose for sector scanning is to perform detailed analysis of developing storms in a particular part of the CBS6 coverage area. The radar rotation can also be stopped to perform a range height analysis. The radar, in a range height mode, scans the vertical profile of a storm, providing valuable data on the structure of the storm and the presence of hail aloft.
The theoretical maximum precipitation detection range of the Instant Doppler 6 radar system is approximately 350 miles. The reflectivity and the elevation from which the precipitation is falling, however, ultimately determines the range the system will first detect rain, hail, or snow. For example, large thunderstorms with highly reflective cores will be detected several hundred miles from the radar site. Conversely, very light snow, which is not as reflective and typically falls from a lower elevation, will first be detected by Instant Doppler 6 at a range closer to the radar site. There will always be some variability on precipitation detection depending on the type and intensity of the weather occurring. This is typical with any radar system.
One of the most important features of the Instant Doppler 6 radar system is its ability to process velocity data. Optimum velocity processing occurs within 60 miles of the radar site. In velocity mode, the system is able to detect winds blowing towards and away from the radar. The velocity data is critical in alerting us to the presence of storm rotation and the potential of tornadoes on a live basis. The radar also scans for turbulence. In turbulence mode, Instant Doppler 6 detects areas of high wind alerting to the possibility of severe weather developing on the ground.
At CBS6, we have the option of displaying Instant Doppler 6 radar data on two separate display systems. The radar's display system consists of six basic range maps, 25 nautical miles, 50 nm, 75, nm, 100 nm, 150 nm, and 200 nm. These broad range maps are useful in detecting and tracking the motion of large scale precipitation shields as well as individual t-storms. The radar's display system also allows for live street level mapping of radar data and automatic storm tracking as well as a flash option to highlight areas of intense precipitation. We can also display Instant Doppler 6 data on our Storm Track Doppler radar display and storm tracking system giving us great flexibility in covering local storms.