Vaisala WRK200 Technical data

Vaisala Weather Radar WRK200

Dual polarization adds
new dimension

The Vaisala Weather Radar
WRK200 is a dual polarization
C-band Klystron Doppler Weather
Radar. The radar operates in either
Simultaneous Transmit and Receive
of H and V (STAR) mode or Linear
Depolarization Mode (LDR) mode ,
during which H alone is transmitted
and both are received. The
polarization variables, depending on
the mode, are ZDR, RHOHV, PHIDP,
KDP and LDR. However, the goal
of polarization radar is not only to
produce and display these outputs;
it is also to expand the capabilities
of the radar for the operational
forecaster.

The WRK200 provides the following
benets:

• Hydrometeoridentification

• Attenuationcorrection

• Dataqualityimprovement

• Improvedrainfallestimates,

based on KDP

S-band performance at
a C-band price

Attenuation by intervening heavy
precipitation has been a long-standing
problem with C-band weather radars,
making S-band radars preferable,
especially in tropical environments
where heavy rain is common.
However, with dual polarization, the
radar performs accurate, real-time
attenuation corrections. The benet
is that you can obtain the same
precipitation measurement accuracy
using the WRK200 as with an S-band
system that costs typically two or
three times more.

More accurate
precipitation measurement

Eliminating non-meteorological
targets and correcting attenuation can
substantially improve precipitation

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Features/Benefits

Vaisala’s light-weight, semi-

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yoke-style pedestal

1 degree beamwidth low side

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lobe antenna

>35 dB integrated cross-

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polarization isolation

Comprehensive BITE

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Improved interference filtering

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Feed forward control loop

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to allow extremely fast and
precise antenna movement

Dual channel digital IF receiver

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Precision horizontal and

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vertical beam matching

Built around Vaisala Sigmet

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RVP900 signal processor

Integral flat screen display for

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local maintenance

Remote control/monitoring

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Rainfall estimation based on

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KDP

Accurate attenuation

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correction

250 kW klystron transmitter

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with low-maintenance solid­state modulator

Option: Built-in dual channel

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receiver calibration

measurement. However, the WRK200
goes further by providing KDP-based
measurement of the precipitation
rate. Unlike the reectivity (Z),
KDP is directly proportional to the
precipitation rate, independent of the
radar calibration and unbiased by
intervening clutter or partial beam
blockage. This makes the KDP very
robust in measuring moderate and
heavy rain.

Technical data

Transmitter

Type Klystron VKC8387
Operating frequency range 5.6 - 5.65 GHz
Peak power 250 kW
Average power max 550 W
Duty cycle 0.0022
Pulse widths Typical 0.5, 0.8, 1.0, 2.0, max 5 µs
PRF 250 to 2125 Hz
Modulator Solid state
Modes STAR or LDR
Phase stability ≤0.1 deg rms

Antenna

Type Center-fed parabolic reflector
Diameter 4.5 m
Gain (typical) 45 dB
Beam width <1 degree
Peak side lobe (typical) -28 dB
Peak on horizontal axis (typical) -33 dB
Integrated cross-pol isolation ≤ -35 dB
H/V alignment (squint angle) <0.1 degrees
Weight 620 kg

Pedestal

Type Semi yoke elevation over azimuth
Elevation range -2 to 108 degrees
Maximum scan rate 40 deg/sec
Acceleration 20 deg/sec
Position accuracy 0.1 deg
Weight 910 kg (total with antenna 1530 kg)
Motors Brushless AC servo

RF-to-IF Receiver

Type Dual stage, dual channel IF downconverter
Dynamic range (1µs pulse) >96 dB (option >110 dB)
IF frequency 442/60 MHz
Image rejection >50 dB
Phase stability 0.1 deg rms
Tuning range 5.5 - 5.7 GHz
Noise figure

< 2 dB

Digital IF Receiver and Signal Processor RVP900

Type Vaisala Sigmet RVP900
IF digitizing 16 bits, 100 MHz in 5 channels
Range resolution N*15 m
Number of range bins Up to 4050
Velocity dealiasing Dual PRF 2x, 3x, 4x
Range dealiasing by phase coding
Clutter filters fixed, adaptive or GMAP to >60 dB clutter

System Specifications

PHYSICAL DIMENSIONS

Cabinet (w x h x d) 1400 x 1800 x 1300 mm
Cooling: Air-conditioned and forced air
Weight 992 kg
Total height 1890 mm

CABINET ENVIRONMENT

Operating +5 °C to +40 °C, 0 to 95 %RH, non condensing
Recommended +15 °C to +25 °C
Storage -50 °C to +50 °C without oil

-10° to +50˚C with oil

ANTENNA/PEDESTAL ENVIRONMENT

Operating -40 °C to +55 °C, 0 to 95 %RH, non condensing
Storage -50 °C to +60 °C

INPUT POWER

Voltage 230/400 VAC ±10 %, 50 - 60 Hz ± 5 %

POWER CONSUMPTION

2

Cabinet 8720W max. with UPS

7850W max. without UPS

Antenna/pedestal 1050 W (max), 200 W (typical)

Options

Radome 6.7 m, foam core sandwich, random panel
Automatic calibration
Forward and reverse transmitted power monitoring

cancellation

Radar Controller

Type Vaisala Sigmet RCP8 with IRIS/Radar
Scan modes PPI, RHI, Volume, Sector, Manual
Local display Real time, ascope, BITE, products

For more information, visit
www.vaisala.com or contact
us at [e-mail]

Ref. B21081 1EN-A ©Vaisala 2010

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to change without notice.