The transmitter is identical to the NEXRAD WSR-88D transmitter and is supported by the NWS National Reconditioning Center in Kansas City, MO. The S-band transmitter operates at dual RF pulsewidths of 1.5 and 5.0 μs and variable PRF (pulse repetition frequency) ranging between 300 and 1300 p.p.s. The transmitter has demonstrated a phase stability of better than 57 dB. The performance is achieved with a klystron amplifier cathode pulsed by an all-solid-state line-type modulator. Special attention is given to modulator pulse regulation, output regulation and inverter timing in the filament supply, and spectral conditioning in the solid-state RF driver. The peak modulator power level of 1.5 MW is capable of producing a peak RF output in excess of 750 kW. The transmit pulse is tapered and filtered for minimum RF interference. The 28 foot reflector is a high-compliance aluminum structure providing -28 dB first sidelobes and at least -31 dB integrated cross polar isolation.
Polarization switching is done by an NCAR built mechanical switch which will provide 49 dB transmit isolation. For alternating H/V pulses, this isolation is comparable to a dual transmitter configuration. A separate receiver for each channel provides 40 dB receive isolation. Copolar and crosspolar receivers are used to provide high data quality differential reflectivity and differential phase measurements.
Pulse pair and dual polarization processing is performed by a Vaisala RVP8 receiver. The processor is PC based and ingests the I/Q time series from the RVP8. Real time ground clutter mitigation is accomplished with the NCAR developed CMD (Clutter Mitigation Decision) algorithm. The spectral based clutter filter provides about 50dB clutter rejection.
