Texas Tech University.

Ka-band Mobile Doppler Radar Trucks

KA-Band Doppler Radar

One of NWI's two Ka-band radar trucks in the field collecting data.

NWI has two mobile Ka-band Mobile Doppler Radars. These fully coherent, pulse compression Doppler radar systems utilize traveling wave tube technology and provide the ability for four-dimensional mapping of a wide spectrum of atmospheric phenomena with very-fine spatial resolution useful for both the atmospheric science and engineering communities.

These data platforms allow our researchers to bring the radar instrumentation to the storm (instead of having to wait for the storm to arrive on their doorstep). They also enable four-dimensional mapping of atmospheric events which is useful for both atmospheric science and for wind engineering fields.

The radars are designed to enhance the sensitivity and the resolution of the data collected and allows more in-depth study of fine-scale atmospheric motions. They also have a higher resolution than that usually provided by other types of equipment which helps researchers "see" through the heaviest rains without losing much signal which means clearer (and more useful) data in the end.

The white dome on the bed of each truck houses the radar and protects it from inclement weather - called a Ra-DOME and looks very similar to a large soccer ball.

Studying severe weather and tornadoes can be tricky as these weather events are often "small" enough to just fit between permanent weather observation stations which means that they can "slip through the net" data-wise. StickNets and Ka-band radar trucks are able to "zoom" in to the most important parts of the storm whilst staying a safe distance away from the dangerous weather.

By filling in the data "gaps", both the Ka-band radar trucks and the StickNet platforms provide a much more in-depth picture of the storm/weather event evolution over a period of time. This can lead to more accurate storm forecasts which may mean reduced wind damage and lower loss of life.

(Photo credit: Patrick Skinner, NWI Ph.D. student.)



TTU Ka-band Radar Specifications:

Transmit Frequency 34.86 / 35.06 GHz (for TTUKa-1 / TTUKa-2)
Transmit Power 200 watts peak, 100 watts average
Transmitter Type: TWTA, 50% duty cycle
Antenna Type Cassegrain feed, epoxy dielectric
Antenna Gain 56 dB
Antenna 3dB BW 0.33 degrees
Polarization Linear, horizontal
Waveguide WR-28, pressurized
PRF Variable, up to 20KHz
Pulse Width 4 widths, variable from 30 nsec to 80 usec
Gate Spacing 12 meters
Receiver Dual block up/down converter
IF Frequency 60 MHz
Pedestal System Orbit AL-4016, 6 rpm max axis rotation
DSP Sigmet RVP-900 with Tx IF modulator drive
Modulation Pulse, Linear FM Chirp, Non-linear FM Chirp
Vehicle Chevy C5500 crewcab, custom bed
Plaform Stabilization Computer assisted hydraulic leveling system