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Stalker Surface Velocity Sensor


The Stalker Speed Sensor SVR is the ideal solution for OEM projects where accurate, reliable water flow measurement is a primary requirement. Backed by nearly two decades experience in microwave radar and 22 radar-related patents, the Speed Sensor SVR is self-contained in a waterproof enclosure and only needs 12 VDC to operate.

Ideally Suited for Water Flow Measurement
The Speed Sensor SVR features a rugged cast-metal exterior and the world’s most sensitive transmitter/receiver as well as miniaturized and modernized electronics. Its direction sensing software and updated algorithms position the Speed Sensor SVR as a new-generation radar ideal for the task of accurate and reliable water flow measurement. Moreover, the Speed Sensor SVR’s Ka Band performance measuring water flow is superior to the K Band used by some of its competitors’ radars.

User Adjustable Tilt Compensation
To make it better suited for measuring from elevated perspectives, the Speed Sensor SVR can be easily adjusted by the end user to compensate its speed reading based on the angle that the radar points at the target flow.

Wide Speed Range & Settings
The Speed Sensor SVR has a speed range of 0.2 m/s to 18.0 m/s – from below 1 mph to over 40 mph – with an accuracy of ±0.1 m/s. And it measures in meters/second, feet/second, miles per hour, and kilometers per hour.

Software Upgradeable
Utilizing a state-of-the-art Digital Signal Processor (DSP), the Speed Sensor SVR provides a level of performance, convenience, and accuracy previously unavailable. The DSP performs the critical filtering and timing functions required for speed measurement in its software, as opposed to hardware. This provides less unit-to-unit variation, more reliable performance, and easier maintenance. One unique feature is that it can be upgraded in the future by simply installing new software, preventing obsolescence!

And a Lot More
Adjustable tilt compensation, settings’ range, and DSP, combined with direction sensitivity, and 4 levels of sensitivity all make the Speed Sensor SVR the new standard in water flow measurement.

Field Configuration


Turns the microwave transmitter On or Off

Radar Zone

Away, Closing or Auto directional sensitivity may be selected

Horizontal Angle

Angles from 0° to 60° may be selected in 5° increments


4 levels of field sensitivity may be selected (1/2/3/4 max)

Test Mode

Initiates a speed sensor self-test followed by a 60 second tuning fork mode, during which time directionality screening is disabled and the speed sensor will respond to any target direction (away or closing) or to non-directional targets (like tuning forks)

Factory Configuration


FT/S (feet.sec), M/S (meters/sec), MPH (miles/hour), or KPH (kilometers/hour)

Leading Character Zero

Space (ASCII 20h) or “0” (ASCII 30h) for ASCII formats (A, B, S)

Serial Port Baud Rate

The serial port operates at 8 data bits, no parity and 1 stop bit (8N1) with the following selectable baud rates: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400

Serial Port Data Format

None – no data output

‘A’ – Averaged velocity output (continuous)

‘AP’ – Peak Speed only (continuous)

Communications Protocol


Auto Test Mode

Automatic test runs always or only when the radar transmitter is on.

Microwave Specifications


Conical horn



3DB Beamwidth

12° +/-

RF Source

Gunn-Effect diode

Receiver Type

Two Direct-Conversion Homodyne receivers using four low-noise Schottky battier mixer diodes

Power Output

10 mW minimum

15 mW nominal

25 mW maximum

Power Density

1 mW/cm2 maximum at 5 cm from lens

General Specifications


Surface Velocity Radar Sensor

Operating Frequency

34.7 GHz (Ka-Band)


+/-100 MHz

Power Requirements

Voltage: 9-16 VDC

Current: (at 12 VDC nominal)

Transmitter on: 470 mA

Transmitter off: 100 mA


Operating: -30° to +70°C, 90% relative humidity

Non-operating: -40°C to +85°C


Weight:  1.15 lb. (0.52 kg)

Diameter:  2.6 in. (6.7 cm)

Length: 4.7 in. (11.8 cm)

Case Material: Aluminum Die Cast


+/- 0.1 M/S

Auto Self-Test

Performed every 10 minutes while transmitting

Speed Range

1 M/S to 180 M/S

Verticle Angle Accuracy


Verticle Angle Resolution