Chill Radar Dual Polarization

The CHILL radar was originally designed as dual polarization radar. It was put into operation in late 1971. The original concept was a dual frequency X-band and S-band system. In 1972, the idea of using it as polarization radar was suggested by Drs. Tom Seliga and Viswanathan Bringi. After several years, the X-band radar was discarded and the system became a dual polarization radar instead. This discussion outlines the changes that were preformed on the system to make it a good polarization system. The radar was dual polarization capable from the beginning with a switch which changed the polarization of the transmit signal. A short list of the changes that were made in the radar and there success and problems are presented. The changes started with an electrical operated switch (original design) which took a second to switch but no special processing; a modified processor and the same switch changing to a 4 second cycle; a ferrite switch with 2 microseconds switching time and changing the processor to one with more channels; two channel separate transmitter and receiver; new antenna; and finally a second new antenna. Most of these upgrades also involved signal processing updates.