Stevens Surface Velocity Radar Manual Velocity Radar User’s Manual Stevens Water Monitoring...

Surface Velocity Radar

User’s Manual

Stevens Water Monitoring Systems, Inc. 12067 NE Glenn Widing Drive, Suite #106

Portland, OR 97220 USA

Tel: (503) 445‐8000 Fax: (503) 445‐8001

Web: www.stevenswater.com E‐mail: [email protected]

Stevens Water Monitoring Systems, Inc. Page | 2

Table of Contents About this Manual ........................................................................................................................................ 4

1. Safety Information .................................................................................................................................... 4

2. Receiving Inspection ................................................................................................................................. 6

3. Getting Started .......................................................................................................................................... 7

3.1 Introduction ........................................................................................................................................ 7

3.2 Battery Charging ................................................................................................................................. 7

3.3 Removing the Battery Holder ............................................................................................................. 7

3.4 Battery Installation .............................................................................................................................. 8

3.5 Inserting the Holder into the SVR ....................................................................................................... 8

3.6 Charging the Batteries ........................................................................................................................ 9

3.7 Charge Status Indicator (LED) ........................................................................................................... 10

3.8 Battery Run Time .............................................................................................................................. 11

3.8.1 Auto Power Off .............................................................................................................................. 11

3.9 Replacing Batteries ........................................................................................................................... 11

3.10 Connecting the Power Cord ............................................................................................................ 11

3.11 Plug In the Power Cord ................................................................................................................... 11

3.12 Control Panel Functions .................................................................................................................. 11

4. Components ............................................................................................................................................ 12

4.1 Control Buttons ................................................................................................................................. 12

4.2 Display ................................................................................................................................................... 13

4.2.1 Number Segments ......................................................................................................................... 13

4.2.2 Status Indicator Icons ..................................................................................................................... 13

4.4 Mounting Configurations .................................................................................................................. 14

5. Operating Modes .................................................................................................................................... 15

5.1 Menu ................................................................................................................................................. 15

5.1.1 Backlight ......................................................................................................................................... 16

5.1.2 Display Function COS ..................................................................................................................... 16

5.1.3 Display Function U ......................................................................................................................... 17

5.1.5 Display Function SEN – Sensitivity Display and Adjustment .......................................................... 18


6. Measuring Surface Velocity .................................................................................................................... 19

6.1 Introduction ...................................................................................................................................... 19

6.2 Taking a Measurement ..................................................................................................................... 19

7. Angle Compensation ............................................................................................................................... 22

7.1 Vertical Angle Compensation ............................................................................................................ 22

7.2 Horizontal Angle Compensation ....................................................................................................... 23

8. Serial Output ....................................................................................................................................... 24

9. Performance Tips .................................................................................................................................... 26

9.1 How Radar Works ............................................................................................................................. 26

9.2 Interference Sources and Remedies ................................................................................................. 26

9.2.2 Electromagnetic Interference (EMI) .............................................................................................. 29

9.2.3 Feedback Interference ................................................................................................................... 29

9.2.4 Radio Frequency Interference (RFI) ............................................................................................... 29

9.2.5 Scanning ......................................................................................................................................... 29

9.2.6 Environmental Factors: Wind, Rain, & Snow ................................................................................. 29

10. Care, Cleaning, and Storage .................................................................................................................. 30

11. Specifications ........................................................................................................................................ 30

11.1 Measurement Specifications .......................................................................................................... 30

11.2 Factory Default Settings .................................................................................................................. 30

11.3 Antenna Parameters ....................................................................................................................... 30

11.4 Environment .................................................................................................................................... 31

11.5 Voltages ........................................................................................................................................... 31

11.6 Power Consumption........................................................................................................................ 31

12. Frequently Asked Questions (FAQ) ....................................................................................................... 32

13. Warranty ............................................................................................................................................... 34

14. Service Return Procedure ..................................................................................................................... 35


About this Manual

This manual contains valuable information to help you set up, use and maintain your radar, so you can

extend its life and keep it at peak performance. Please take a moment to read through it, and keep it

handy for future reference.

Note the following symbols in this manual:

Indicates a warning message about safety precautions. Please read it carefully.

Indicates a helpful tip or precaution to note.

1. Safety Information

All service needs should be referred back to the manufacturer.

WARNINGS

Do not over voltage the radar ‐ it can damage the unit! See notes.

When replacing batteries in the SVR you should replace all 6 with new batteries even if you suspect that only one cell is defective.

Use rechargeable Nickle‐Metal‐Hydride batteries only.

The SVR is designed to operate off of conventional +12 VDC (+10.8 to +16.5 VDC) from the power cable. In addition, the SVR is also designed to operate at 7.2VDC from the internal batteries. Over voltage to the power cables or incorrect batteries can cause damage.


Opening the SVR (other than battery replacement) automatically voids any warranty still in effect. There are no user serviceable parts inside.

Do not expose the SVR to excessive moisture. Never submerge the device. Violation of these guidelines may void the warranty.

Do not drop the SVR on hard surfaces since damage could occur. Units damaged by dropping or abuse are not covered for warranty repair.


2. Receiving Inspection

When you receive your radar, inspect all components for freight damage that might have

happened during shipping or unloading.

Notify the freight company immediately of any damage, preferably while the driver is present.

Record the damage on the bill of lading and keep a record of the problems or damage.

The package should include the following pictured items along with this User’s Manual:

Handheld SVR unit Detachable power cable Batteries and battery holder


3. Getting Started

3.1 Introduction

The SVR is a hand‐held surface velocity radar (SVR) gun specifically designed to measure the surface

velocity of water—great for use in streams and rivers. Features such as Recall allow you to review the

previous measurement. Other features are selectable through the menu option.

The radar gun features a tilt sensor system, which internally compensates for the cosine angle effect of

the vertical (pitch‐down) angle of the gun to the target. It is not necessary to manually set the tilt

sensor.

Also, the software compensates for the horizontal (yaw) angle created when the gun is aimed at a target

from an angle greater than 10° from the parallel alignment of the gun to the target.

3.2 Battery Charging

The SVR is designed to operate off of six (6) rechargeable Nickel‐Metal‐Hydride batteries (or off the DC

power cord).When you first receive your radar, the batteries will need to be charged for the first time

before using. Once batteries have been charged if you do not use the SVR for 3‐4 weeks, you will want

to recharge the batteries before use in order to get the full run time. To charge batteries for the first

time or to replace the batteries following steps 3.6 to 3.7.

3.3 Removing the Battery Holder

The battery holder is located inside the handle of the SVR and is accessed by means of a sliding door.

When first received, the holder should already have batteries installed, but if not then you will need to

remove the holder and loaded it with batteries. To remove the battery holder slide the battery cover to

the right until the battery holder is released as shown in Figure 3.3.The door can be completely removed

from the slide.

Figure 3.3 Slide the battery door open


3.4 Battery Installation

Insert the batteries into the battery holder following the polarity guide that is on the inside of the

battery holder (Figure 3.4a.) Once properly loaded the battery holder will look like the example in Figure

3.4b

Figure 3.4a

Battery holder with direction indicated

Figure 3.4b

Battery holder with batteries inserted

Notice that the negative side of each battery goes to the spring contacts of the holder.

3.5 Inserting the Holder into the SVR

The battery holder is designed so that it can only make contact with the power connections inside the

gun if the holder is slid into the gun in the correct way. If you look closely at the holder you will see that

there is a positive and negative terminal on it. These need to be inserted into the gun with the terminals

located at the top as shown in Figure 3.5.

Figure 3.5 Insert batteries


Once the batteries have been properly loaded into the holder and the holder has been inserted into the

handle of the gun then the door can be put back in place and slid closed. If you have not already charged

the batteries using an optional NiMH charger, you are now ready to charge the batteries using the

power cable.

If the holder has been placed incorrectly into the handle the door cannot be put back in place and closed.

3.6 Charging the Batteries

The power cable that comes with the SVR can be used to either power the SVR directly from your

vehicle receptacle or to charge the SVR’s batteries. Once the batteries have been properly installed into

the holder and inserted into the handle plug the power cord into the power connector at the base of the

handle by aligning the red dot on the power cord’s plug with the red dot on the connector. Failure to

align the plug with the connector properly will result in damage to the pins of the jack. Reference figure

3.6 for proper alignment.

Figure 3.6 Align the red dots to properly insert power cable.

Next, plug the lighter plug into an active cigarette lighter receptacle in the vehicle. The red led on the

lighter plug should come on showing that power is being applied to the SVR.With the SVR turned off, it

will take approximately 2 hours to fully charge the batteries. Turning the SVR on with the cord plugged

in will stop the charge cycle allowing the gun to be operated from the power cord. Batteries do not

charge when the gun is turned on.


3.7 Charge Status Indicator (LED)

The status of the charge can be determined by the Charge Status Indicator LED located on the bottom of

the handle (See figure 3.7).The table below defines the status.

Fast blinking green light = checking battery condition

Medium blinking green light = charging battery

Solid green light = charged

Solid red light = charging error

Figure 3.7 Charge status indicator LED on bottom of SVR handle

The normal charging sequence is fast blink for 60 seconds, medium blink until batteries are fully charged

(approximately 2 hours for fully discharged batteries) and solid green once batteries are charged.

The gun can be left to charge indefinitely. The charging circuit will automatically shut off once charging is

complete.

The SVR must be OFF or the batteries will not charge. You cannot operate the SVR and charge the batteries at the same time.

Best performance from your batteries is obtained when recharged at temperature between 50ºF (10ºC) and 113ºF (45ºC).Recharging outside of that temperature range may result in reduced battery life or incomplete charging.


3.8 Battery Run Time

How long the SVR can operate between recharges depends upon several factors including the milliamp

hour (mAh) capacity of the batteries, age of the batteries, and how the SVR is used. Generally a set of 6

new 2500 mAh batteries fully charged should run for approximately 1 week between recharges given

normal use.

3.8.1 Auto Power Off

If no key press is detected the SVR will automatically power off after 5 minutes in order to conserve

battery life.

3.9 Replacing Batteries

When replacing the batteries with new ones remember to use only rechargeable Nickel‐Metal‐Hydride

batteries and to replace ALL the batteries at the same time even if you suspect that only one battery is

bad. Follow the instructions listed in steps 3.2 through 3.7 for proper installation and charging when

replacing batteries.

3.10 Connecting the Power Cord

If you choose to run off the power cord instead of the internal batteries, connect the power cord to the

receptacle on the bottom of the SVR being sure to properly align the plug on the power cord to the

connector on the bottom of the SVR. The SVR automatically will switch from the internal batteries to the

power cord for power when the unit is turned on.

3.11 Plug In the Power Cord

Plug the radar’s power cord into your vehicle’s cigarette lighter receptacle. If you are using a separate

battery pack as a power source, plug the radar’s power cord into the battery pack’s receptacle.

3.12 Control Panel Functions

The operation of the SVR is controlled by the five‐button key pad on the back of the unit.


4. Components

4.1 Control Buttons

Figure 4.1

Faceplate (Display and Control Buttons)

Looking at the control buttons from left to right the buttons have the following functions:

MENU The MENU button lets you view the options you can change. Repeatedly pressing the MENU button advances through the programmable features. SEL The select (SEL) button lets you choose the settings in each of the mode options. To change a mode option, press the SEL button. PWR The PWR button turns the radar on and off. When first powered on the SVR will display the screen shown in Figure 4.1.When you power the SVR off the word OFF will appear in the display and the unit will power down.

RCL When the recall button (RCL) is pressed the unit enters recall mode if the following are true:

The unit is not transmitting.

All 10 measurements have been completed and the speed result has been displayed. The function is active if the letter "r" appears on the left‐hand side of the display.


MODE The MODE button lets you change the resolution of the display. You can choose to have the speed displayed in 10ths or 100ths.

4.2 Display

4.2.1 Number Segments

The 5 large digits (88888) display the speed. Resolution is determined by the placement of the decimal

point. The icons indicate the status.

4.2.2 Status Indicator Icons

When first turned on the SVR performs a segment check of the display to show that all segments and

icons are working. The following icons will appear at the top and bottom of the display screen, however

not all of the icons are for features used by the SVR. The icons that represent the features that are used

by the SVR describe the following conditions:

Figure 4.2.2 Number segments and status indicator icons.

POWER When POWER appears, the power is on. LOW BAT The LOW BAT icon indicates that your internal batteries (or your separate battery pack) may be low on power. The system will not transmit or display any new speeds while LOW BAT appears and the display will remain blank. XMIT XMIT means the radar is transmitting. HOLD HOLD indicates the system is not transmitting.


FPS Indicates that the gun is set to display speeds in feet‐per‐second. M/S Indicates that the gun is set to display speeds in meters‐per‐second. Once the segment check test is completed the display will show the POWER, HOLD and the units of measure (FPS or M/S) icons along with 5 dashes ( ‐ ) across the center of the display. The SVR is now ready to use.

Figure 4.2b The display showing the segment check test is completed and the SVR is ready to use.

4.4 Mounting Configurations

The radar is designed for hand‐held operation. Optionally, you can mount it to a standard camera tripod.


5. Operating Modes The MENU and SEL buttons on the SVR control panel lets you review and change programmable

settings. The radar gun will remember the settings you last set when it is turned off and will power up

with them.

5.1 Menu

You can use the factory default settings or you can select your own settings. To select a setting,

repeatedly press the MENU button until the setting you want to change appears. Then release the

MENU button and press the SEL (select) button to advance through the selections for that setting. When

you have made your selection, release the button and your new settings will be in effect. If neither

MENU or SEL is pressed after 2 seconds, the radar gun will return to normal operating mode, capturing

whatever settings you have selected to that point. Table 5.1 shows the menu setting choices.

The menu options are:

• bl = Backlight (on/off)

• C = Cosine Adjustment (0º to 60º in increments of 5º)

• U = Units of measure (European meters‐per‐second or USA feet‐per‐second)

• A =Angle (reporting only)

• SEN = Sensitivity (1‐10 with 10 being maximum sensitivity)

Table 5.1 Menu Settings


5.1.1 Backlight

Use the backlight function to turn the SVR's display backlight on or off. Turning the backlight off when

not needed saves battery power.

Figure 5.1.1

Backlight mode

5.1.2 Display Function COS

Use COS (cosine) to adjust the cosine correction angle for the horizontal (yaw) angle (the valid range is

0° to 60° in increments of 5°).The correction angle chosen will be saved and retained until you change it

again

Figure 5.1.2 Cosine mode


5.1.3 Display Function U

Sets the units of measure that speed will be displayed in. Choose “EUr” to display for meters‐per‐second

(m/s) or “USA” to display feet‐per‐second (f/s).

Figure 5.1.3 Units mode

5.1.4 Display Function A – Vertical Angle Display

Used to verify that the SVR is reading vertical angle correctly. The vertical angle may be checked by

pressing the Menu button until the letter "A" is shown in the display and then pressing the SEL button.

As you move the gun up and down the angle that the gun is currently at will be displayed. To exit the

mode press the MENU, RCL or PWR buttons.

Figure 5.1.4 Vertical Angle


5.1.5 Display Function SEN – Sensitivity Display and Adjustment

Higher numbers tell the gun to pickup surface velocity from a further distance. Lower numbers reduce

the distance. If the sensitivity is too high the indicated velocity may be unpredictable and erratic. Choose

a value that works best for the site you are taking measurements at.

Figure 5.1.5

Sensitivity Mode


6. Measuring Surface Velocity

WARNINGS Do not put the radar gun in the water. This will damage it. The SVR measures the water surface only from outside the water.

6.1 Introduction

To begin a velocity measurement, point the radar gun at the water and the press the RCL button. The

surface velocity can be measured flowing toward or away from the gun. A dash ( ‐ ) on the left hand side

of the display (as seen in Figure 6) will show and continue to flash until the velocity stabilizes.

The dash will stop flashing when the SVR has performed enough measurements to display an averaged

and reliable velocity. The SVR will begin taking an additional 10 measurement starting with zero (0) and

proceeding up to 9 as each measurement cycle is completed. Once all additional 10 measurements have

been completed the average of all the measurements are displayed. This will take 60 seconds to

complete.

Figure 6.1

The dash ( ‐ ) appears on the left hand side of the display window

6.2 Taking a Measurement

Turn the SVR on by pressing the PWR button. Once the display segment check is completed the gun is

ready to use.

Push and release the RCL button. The SVR shows a dash ( ‐ ) on the left hand side of the display.

The dash ( ‐ ) keeps flashing, indicting the SVR is taking measurements. The velocity is updated


once per second. This velocity may vary significantly while the SVR focuses its data processing.

Towards the end of the first 10 seconds, the displayed velocity will be accurate. (Do not press

the RCL button again or the measurement cycle will be restarted.)

After 10 seconds the dash ( ‐ ) is replaced by the number "0" (zero) indicating that the next

measurement cycle has started. The speed shown is the average velocity over the last 10

seconds and will remain in the display until the current measurement cycle is completed. The

leading “0” will continue flashing.

After 5 seconds the measurement cycle is completed and the "0" (zero) is replace with the

number "1" indicating that the next measurement cycle has started. The speed shown in the

display is the average velocity over the last 15 seconds and will remain unchanged until this

cycle is completed. The number “1” will continue flashing.

After 20 seconds, the number in the left hand side of the display updates to "2" and runs the

same speed measurement as described previously. The SVR will continue to take speed

measurements every 5 seconds and display the new average speed and update the number

shown on the left hand side of the display until all measurement cycles have been completed.

After 60 seconds have passed, the SVR will have completed ten separate 5‐second batches of

velocity measurements. The display will indicate the average of these measurements.

Press the MODE button if you want to change the display resolution. The speed can be displayed

in either 10ths or 100ths.

If the user presses the RCL button once the speed measurement cycles have finished, the reading will be

canceled and the SVR will begin taking a new measurement

Figure 6.2

The average of all 10 measurements (Display is set to show in 10ths).


NOTE If there are fluctuations of more than 0.5 to 0.8 f/s (0.15 to 0.24 m/s) during a measurement interval, it is advised to review the final value. Consistent readings confirm the validity of the result, so we recommend taking the measurement more than once.

Because the SVR measures the Doppler effect from the water surface, the SVR requires a certain

amount of return energy.(See section 9.1 How Radar Works.) Particulate material and/or floating debris

(seeding) on the surface and surface water roughness provide this effect.

The SVR easily measures the velocity at which the particulate material moves in high‐flow conditions.

This provides the accuracy of the surface flow.For velocities of more than 1 to 2 f/s (0.30 to 0.60 m/s),

floating debris and particulate material provide an ample return signal to the radar gun for

measurement. Water roughness also gives a good signal return. Ripples and crosscurrents produce

velocities in all directions. During a measurement, the SVR reads all the velocities and averages them

into a resulting single value, based on the amount of signal return to the antenna.


7. Angle Compensation Because surface velocity readings must be taken from a stationary, dry position, often a river bank or

bridge, readings are necessarily affected by angle between the radar's beam and direction of water flow

(see the section on Angular Interference).

The SVR compensates for this effect, referred to as cosine angle, both horizontally with user

programmable yaw correction and vertically with an automatic internal tilt sensor

7.1 Vertical Angle Compensation

Figure 7.1

The SVR tilted pitch‐down at 60º vertical angle

The SVR's internal tilt sensor automatically compensates for the vertical angle at which you aim the gun

to the target, up to 60°.You do not need to manually set the tilt sensor. However, you must hold the gun

still at a constant vertical angle while taking a velocity measurement.

The SVR indicates when the pitch‐down angle exceeds 60° by displaying "tilt". While "tilt" appears in the

display window, the radar gun does not record velocity measurements. To continue taking water surface

velocity measurements, tilt the gun to an angle less than 60° until the "tilt" indicator no longer appears.


Figure 7.1

The display when the vertical (pitch‐down) angle exceeds 60º

The vertical cosine angle will always be calibrated at the factory and should never need calibration in the

field. However, the vertical angle of the SVR can be verified as being correct at any time.To do so refer

to the section 5.1.4 Display Function A – Vertical Angle Display

7.2 Horizontal Angle Compensation

Aiming the radar gun at the target at a horizontal angle greater than 10° creates a cosine error, which

results in the radar displaying a spurious reading. To eliminate or greatly reduce this error, set the

horizontal angle compensation option to the angle that you plan to aim the radar gun to the target.

Then aim and hold the gun at this set angle during the entire velocity measurement.

To set the horizontal angle compensation option, press the MENU button until COS (cosine) appears in

the display. Then press the SELECT button.

Each time you press the SELECT button 00, 05, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 appears,

representing the horizontal angle degrees in which you plan to hold the gun. Select the angle by

displaying the number until the radar gun times out.

Now the gun is set at this angle selection and remains in this mode until you change it. This setting will

appear the next time you enter this menu option.


Figure 7.2

The horizontal angle setting for 5º

8. Serial Output

The SVR has an RS232 communications port on the bottom of the handle. Using a custom RS232

communications cable, you can connect the radar and transmit data to display signs and PCs for

recording and analyzing speed data. Figure 8 illustrates the location.

Figure 8

Port location.

The serial communication of the RS232 communications port has the following characteristics (8:n:1)

and is transmit only:

One (1) start bit

Eight (8) data bits

No parity

One (1) stop bit


Transmission at 1200 baud

The unit transmits data as ASCII symbols in the following digit sequence:

ASCII [hundreds][tens][ones]

Carriage return<CR>

(<CR> = ASCII decimal value 13)

The radar unit sends the data in this sequence when the TARGET speed display changes. When you press

the LOCK button, the radar transmits the following digital sequence:

[hundreds][tens][ones]<CR>

(<CR> = ASCII decimal value 13)


9. Performance Tips Understanding potential radar interference and what to do when it occurs can greatly increase the

radar’s performance.

9.1 How Radar Works

Determining a velocity begins with the radar gun transmitting and directing a beam of microwave

energy (radio waves) at an approaching (or receding) target. When energy from this beam strikes the

target, a small amount of energy from this beam is reflected back to the antenna in the radar device.

The reflected signal frequency shifts by an amount proportional to the velocity of the target. This is

known as the Doppler effect. The radar device then determines the target velocity from the difference in

frequency between the transmitted and reflected signal.

When the antenna transmits the beam of radio waves, the beam forms an elliptical pattern on the

target area. The beam’s size depends on the distance between the antenna and the target. The

horizontal beam width is 12°.The detection area becomes larger as it becomes farther away from the

antenna.

Figure 9.1

Radar beam detection area When you point the SVR about 10 feet (3 meters) from the water surface, it measures an elliptical beam

pattern of 2 feet (61 cm) in diameter. Keep this in mind when making measurements of a stream width.

Take several readings to completely cover the full width of the stream.

9.2 Interference Sources and Remedies

When properly installed and operated, Doppler radar technology is extremely accurate and reliable.

However, variations in the environment can cause situations and circumstances, which can cause

spurious (erratic and unusually low or high) velocities to display. Signs that a velocity is spurious can

include the following characteristics:

a reading appears when no target is in the operational range of the antenna

a target entering the operational range overrides the interference signal, causing the display

velocity to change suddenly


interference is irregular and does not provide a valid target history.9.2.1 Angular Interference

(Cosine Effect) The cosine effect causes the radar device to display a velocity which is lower than

the actual water surface velocity. This condition exists whenever the target's path (the water

flow direction) is not parallel with the radar gun’s antenna. As the horizontal (yaw) angle

between the antenna and the target's directions of travel increases, the displayed velocity

decreases. Ideally, an angle of zero (0°) is best.

Figure 9.2.1

An angular error occurs when the target's path is not parallel to the radar antenna.

Small angles (less than 10°) have little effect on accuracy. As the angle increases, the displayed target

velocity erroneously decreases, as the following table, Table 9.2.1, shows. At 90°, the target velocity is

0—grossly incorrect.

You will see numbers such as these if you do not set the horizontal angle compensation option in the

software menu. (For how, see Section 7.2 Horizontal Angle Compensation.)


Horizontal Angle Degrees

Actual velocity in f/s

0 1º 3º 5º 10º 15º 20º 30º 45º 60º 90º

Displayed speed:

3 3.0 3.0 3.0 3.0 3.0 2.9 2.8 2.6 2.1 1.5 0.0

5 5.0 5.0 5.0 5.0 4.9 4.8 4.7 4.3 3.5 2.5 0.0

7 7.0 7.0 7.0 7.0 6.9 6.8 6.6 6.1 4.9 3.5 0.0

9 9.0 9.0 9.0 9.0 8.9 8.7 8.5 7.8 6.4 4.5 0.0

11 11.0 11.0 11.0 11.0 10.8 10.6 10.3 9.5 7.8 5.5 0.0

13 13.0 13.0 13.0 13.0 12.8 12.6 12.2 11.3 9.2 6.5 0.0

15 15.0 15.0 15.0 14.9 14.8 14.5 14.1 13.0 10.6 7.5 0.0

17 17.0 17.0 17.0 16.9 16.7 16.4 16.0 14.7 12.0 8.5 0.0

19 19.0 19.0 19.0 18.9 18.7 18.4 17.9 16.5 13.4 9.5 0.0

21 21.0 21.0 21.0 20.9 20.7 20.3 19.7 18.2 14.8 10.5 0.0

23 23.0 23.0 23.0 22.9 22.7 22.2 21.6 19.9 16.3 11.5 0.0

25 25.0 25.0 25.0 24.9 24.6 24.1 23.5 21.7 17.7 12.5 0.0

Table 9.2.1 Actual and displayed velocities at antenna‐to‐target angles

Table 9.2.1 shows the actual velocities (in the left column) and the velocity that displays (columns on the

right) if you have not adjusted the radar gun for the horizontal (yaw) angle. Note that for angles less

than 10°, the cosine error effect on the velocity is minimal. Also, note that the table reflects only the

cosine error from the horizontal angle. When you introduce a horizontal (yaw) angle and a vertical

(pitch‐down) angle into a measurement, both angles affect the final calculated display velocity.

NOTE The vertical (pitch‐down) angles that are less than 60° are automatically compensated for by the tilt sensor.


9.2.2 Electromagnetic Interference (EMI)

While operating, electric motors can produce EMI.EMI can produce spurious (erratic and unusually low

or high) target velocities. To correct the interference, simply turn off the source of interference.

9.2.3 Feedback Interference

When you direct the radar beam at computer screens, streetlights, and other electronic devices, it can

display spurious (erratic and unusually low or high) velocities. To correct the interference, move the

radar gun’s antenna away from the source of the interference.

9.2.4 Radio Frequency Interference (RFI)

The radar gun can inadvertently process radio energy as Doppler velocities, including that from police

radios, airport radar, microwave transmission towers, CB radio transmitters, and AM/FM transmission

towers. For this type of interference to occur, the radar gun must be operating very close to the radio

transmitter.

9.2.5 Scanning

The SVR is designed for use while attached to a solid mount or hand held in a steady position. Moving or

"scanning" the antenna past stationary objects can cause the system to detect motion. Obtaining a

velocity reading by scanning will not happen when you properly use the radar.

9.2.6 Environmental Factors: Wind, Rain, & Snow

Wind moving across a water surface can produce waves, which result in movement differing from the

main direction of the water flow. In high‐velocity water flow, this effect is minimal or non‐existent and

does not affect the measurement.

However, in low water surface flow, such as conditions below 1 to 2 f/s (0.30 to 0.60 m/s), the wind’s

effect is dominant, so the measurement might not reflect the actual velocity movement. In wind,

position the SVR toward a target area where wind does not affect or minimally disturbs the water

surface, such as under a bridge or in a sheltered area.

Rain and snow can influence the accuracy of measurements. In slow water flow conditions, the vertical

velocity component of rain or snow is dominant. Rain droplets passing in front of the measuring plane of

the antenna and water surface roughness produced by rain droplets contacting the water surface cause

this effect. However, in conditions of rapid water flow, these effects are minimal. The dominant effect is

the surface water flow following the direction of the main open channel.

In these conditions, take measurements under a bridge, structure, or covered area where rain and snow

do not dominate the measurement. Take measurements where the main channel flow is dominant. This

eliminates the potential for errors from environmental factors.


10. Care, Cleaning, and Storage

Avoid spilling food, beverages, and other liquids and substances on the radar device.

When you are not using or transporting the device, store it in its original packaging.

To clean the radar device, use a soft clean cloth, which is free of cleaning solutions.

11. Specifications

11.1 Measurement Specifications

Minimum Velocity 0.3 fps (0.3 m/s)

Maximum Velocity 30 fps (9.1 m/s)

Measurement Accuracy 5% of Reading

Units of measure can be set to read in feet per second (fps) or meters per second (m/s).

11.2 Factory Default Settings

Units M/S (meters‐per‐second)

Horizontal Cosine 0°

Sensitivity 10

11.3 Antenna Parameters

Type K‐Band, IACP Type III

Nominal Transmission Frequency 24.150 Ghz

Nominal Horizontal Beamwidth 12°

Polarization Circular

Nominal Microwave Power Output 7 mW

Maximum Aperture Power Density <1 mW/cm2


11.4 Environment

Ambient Temperatures ‐22°F to +158°F, ‐30°C to +70°C

Maximum Humidity % relative humidity at 99°F (37°C) non‐condensing

Water resistance meets International Robustness Standard IEC 529:1989 and European Community Standard EN 60529 Classification IP55.12°

11.5 Voltages

Supply Voltage Range 8.5 VDC – 16.5 VDC

Power Supply Frequency replaceable NiMH batteries

Low Voltage Threshold 6.1VDC (battery) 8.5VDC (cord)

11.6 Power Consumption

Standby .105 amperes

Antenna ON no target displayed .170 amperes

Antenna ON anything displayed .172 amperes

Antenna OFF segment check "888" .116 ampres

Antenna ON segment check "888" .180 ampres

All currents measured at 13.8VDC with backlight on.


12. Frequently Asked Questions (FAQ) Q. My surface velocity measurement reading is much higher than the last time I took a reading.

A. If the water surface is smooth with very little or no roughness, the SVR is possibly not receiving

enough returning radar energy from it. Try to make your measurement closer to the water or in a region

where some water surface turbulence, roughness, or even floating material is on the water.

Q. I just completed making a measurement and moved to a different spot on the river. Now my

measurements seem off.

A. Check to make sure you have adjusted the horizontal (yaw) angle compensation. In high flow

conditions, an incorrect or improper angle input can yield a significant difference in velocity readings.

Q. The water has some good roughness and waves on the surface, but the radar gun still seems to give

me a higher and/or much lower reading than I expect.

A. Make sure you are not too far away from the water surface when making a measurement. This

distance is sometimes difficult to determine, because the measurement is a function of the amount of

returning signal to the radar gun. The returning signal directly relates to the distance from the water

surface and the water surface roughness. The radar gun makes the best measurements, even for very

low velocities, when it is as close to the water surface as possible. You need to make several

measurements pointing at the same spot. Try to minimize the horizontal (yaw) angle in the

measurement. Also, make several measurements at different vertical (pitch‐down) angles to determine

a consistency in the readings. Make sure you hold the gun steady and at only one angle when making a

measurement.

Q. I am trying to make a velocity measurement that appears to be lower than 2 fps (.60 m/s), but my

readings show a higher velocity.

A. Check for wind effect occurring on the water surface. Wind can affect the measurement of low

velocities, as example below 2 fps (.60 m/s). If possible, make the measurement in two directions, one

of the water flowing toward the gun and one away from the gun. Try to make the measurement by

pointing at the same spot.

Q. I’m making a measurement during a flooding condition. The water is flowing very fast and is very

turbulent and rough with a lot of debris and floating material. Is the gun giving me a good

measurement?


A. YES, turbulent water with floating material on the surface provides a good return signal to the radar.

Note that in these conditions, the radar gun reads many different velocities occurring in numerous

directions. The radar gun measures all these velocities and provides one averaged velocity value.

Q. While making a measurement, the value is changing every 5 seconds.

A. The radar gun measures the velocity in 60‐second intervals. When the first measurement value

appears on the display, it is a result of the radar gun sampling the surface velocity numerous times.(The

radar gun puts the data values in a type of first‐in, first‐out memory buffer.) As the radar gun continues

to take samples, it discards and replaces the older velocity values with newer samples then averages the

values again. The sampling process takes place every 5 seconds within this 60‐second period. This is

because the hydraulics of the water can change. The radar samples the surface water and provides ten

averaged values of surface velocity, each sampled in a 5‐second period. After 60 seconds, the radar gun

averages the ten values together to provide a final velocity value.

Q. When I make measurements, the readings seem to change from high to low velocities to high

velocities, etc.

A. Make sure you hold the gun steady when you take a measurement. The tilt sensor that compensates

for vertical (pitch‐down) cosine error in velocity is very sensitive. Vibration or jerky movements of the

gun cause incorrect angle readings.


13. Warranty

TWO‐YEAR RADAR WARRANTY

Stevens Water Monitoring Systems, Inc. guarantees the radar to be free from defects in workmanship

and material and to operate within specifications for a period of two years. During this period, Stevens

Water Monitoring Systems, Inc. will repair or replace, at its option, any component (excluding batteries)

found to be defective, without cost to the owner, providing you return the unit to the factory.

The full warranty on parts and workmanship does not include normal wear and tear, crushing, dropping,

fire, impact, immersion, over‐tightening of screws or damage from attempted repair or modifications by

unauthorized service agents.

For repairs, simply return the unit (transportation prepaid) directly to Stevens Water. Refer to section 14

Service Return Procedure.

TWO‐YEAR WARRANTY EXCEPTION

If you purchased the unit under a special buying program, such as a state purchase contract, etc., the

above warranty may not apply. Please refer to the buying program contract for the appropriate

warranty terms or contact Stevens Water Monitoring Systems.

If you are interested in an extended warranty contact your sales representative to discuss options.


14. Service Return Procedure

If you have questions, want a quick problem diagnosis, or need to return your radar unit to the factory:

Call Stevens Water Customer Service and ask to speak with a Customer Service Representative.

Have the serial number of the radar unit ready.

Phone: 503‐445‐8000 or 800‐452‐5272

Fax: 503‐445‐8001

If you need to return your radar unit to Stevens Water:

Ask to arrange for a Return Authorization Number. You will need to give the serial number of

the radar that is to be serviced. The serial number is located on the bottom of the handle.

Return ALL of the radar's parts in the original packaging (transportation prepaid).

If so directed, include a note describing the problem and/or the incident that resulted in the

problem. Failure to do so can delay the return of your radar device.

Based on the information that you have given, the Customer Service Representative will issue

you a return authorization (RA) number. Write the RA number on your note and shipping label.

Return the system to: Stevens Water Monitoring Systems, Inc. 12067 NE Glenn Widing Drive,

Suite 106, Portland OR 97220 USA RA# XXXXXX

The customer is responsible for the shipping charges to send the system to Stevens Water Monitoring

Systems, Inc.

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