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Speed/Temp Surface Monitor Pro Trac Ultra-Brite Tender Tool


         Depth Raider Speed and Temperature Monitor

Professional downrigger fishermen understand that different species of game fish prefer different temperature ranges. Additionally, they understand that maintaining a specific range of trolling speeds is not only important to attract game fish but is also important to ensure the lure is running with the proper action.

However, it can be very difficult to predict the speed and temperature of a lure when trolled at varying depths below the water surface. Surface speed and temperature gauges are ineffective at predicting sub-surface conditions since day-to-day environmental effects such as wind speed and wind direction can create underwater currents and drastically alter the sub-surface water temperature.

The Depth Raider system measures and displays this vital speed and temperature information with digital precision. The Depth Raider speed and temperature monitor tells you the exact speed and the exact temperature of your lure at it's running depth.

Theory of Operation - Upon entry into the water, the underwater sensor/transmitter probe unit continuously measures speed and temperature then periodically transmits a digitally encoded RF signal onto the coated downrigger cable. The signal is received by a receiving antenna mounted on the downrigger boom. This signal is then routed to the receiver/display unit via a coaxial cable.

The receiver/display unit continuously monitors for data transmissions from the underwater probe unit. Once a transmission is received, data is decoded from the RF signal and converted into speed and temperature which is then displayed on the LCD display.

Coated downrigger cable is necessary to prevent the lake water from absorbing (attenuating) the signal transmitted from the sensor/transmitter unit. The coating provides electrical isolation from the water since water is a conductor of electricity. Without the coating (or electrical isolation), a portion of the signal is absorbed by the water thereby reducing the signal level at the receiving antenna. Without the coating, as the depth of the probe continues to increase, the signal level at the antenna continues to degrade until it is no longer adequate for proper interpretation by the receiver/display unit. It should be noted that the actual depth of operation without a coated cable can vary greatly from installation to installation, boat to boat, water conditions, etc.

While the Depth Raider system will operate to varying depths without the coated cable; installation of the coated cable is highly recommended to provide proper operation to 200 feet.


      Depth Raider features the smallest Probe on the market!

Sensor/Transmitter Probe Specifications:

Power Source 9V Alkaline Battery
Battery Life Greater than 225 hours of underwater operation, typical
Battery Access Screw-on cap with dual O-ring seal
Turn On           Automatic turn-on when Probe enters the water
Turn Off  Automatic turn-off after Probe is removed from water
Physical Size  6.375” Long x 1.89” body diameter
Body Construction Custom injection molded housing
Internal Construction Electronics 100% sealed in epoxy to prevent water damage
Electronics  Microcontroller based ultra-low-power electronics
Speed Sensor 6 tooth ferromagnetic rotor with electronic magnetic sensor circuitry
Temperature Sensor  Precision temperature sensing device

Sensor/Transmitter Probe Features:

1) Upper connection tab - The probe unit transmits the RF signal onto this stainless steel tab. Attach the downrigger cable to this tab. This connection must be isolated from the water with rubberized electrical tape to prevent the transmitted signal from being absorbed in the water. Rubberized electrical tape is included with the Depth Raider system.

2) Raised Boss - This raised boss is part of the injection molded housing. It's purpose is to provide an electrically isolated flange that the rubberized tape can adhere to ensuring a good seal. This boss is also handy to quickly determine which side of the probe unit connects to the downrigger cable.

3) Lower Connection Tab - This tab is used to connect the downrigger cannonball. Be sure to use an 18”-24” drop leader of lower test. If the cannonball gets snagged on the bottom, its better to lose the cannonball rather than the probe and the cannonball. This tab is internally electrically isolated from the upper connection tab. Therefore, there is no need to use rubberized electrical tape on this interconnect.

4) Ferromagnetic Rotor - We call it a ‘Paddle Wheel’. This device is molded of plastic and magnetic particles. It has 6 teeth or ‘paddles’ around the circumference. Every time a tooth passes by the magnetic sensor located inside the unit, an electrical pulse is generated. The probe unit measures speed by counting these magnetic pulses over a specific period of time.

5) Battery Cap - Remove this screw-on cap to access the battery compartment. The cap features a two-O-ring seal to prevent water entry into the unit. Also, this cap has an aggressive knurled exterior that aids the user in removing the cap with wet, slippery hands. Be sure to keep the O-rings well lubricated with Vaseline or similar lubricants. Tightening the cap without lubricant can quickly damage O-rings.


        Depth Raider features a display with large, easy to read LCD digits


Receiver/Display Unit Specifications:

Power Source          12VDC Boat Power
Current Consumption   <75ma (backlight off),  <500ma (backlight on)
Physical Size   3.25” X 3.75”
Housing Construction Custom injection molded housing
LCD Display     Custom LCD with large .59” tall digits. User adjustable LED backlighting
Temperature 32.0 to 99.9 degrees F
Speed      0.0 to 9.9 MPH
Power Down Mode  Auto shut-off in 30 minutes if no transmissions from Probe are detected
Silicone Keypad Configuration   4 user pushbuttons.  Power On/Off button, Backlight On/Off button, Backlight intensity increase and Backlight intensity decrease
Low Probe Battery Warning  LO BAT icon is activated when probe battery is low.

Receiver/Display Features:

1) Displays temperature at the probe from 32.0 degrees to 99.9 degrees F.

2) Displays speed at the probe from 0.0 to 9.9 miles per hour (MPH)

3) LO BAT icon - when illuminated, the 9V battery in the probe is low and should be replaced soon. The low battery indicator is calibrated to ensure you have a minimum of 8 hrs. of use prior to battery replacement. If this indicator illuminates during an outing the user may continue to use the system for up to 8 hours. Just be sure to replace the battery at the end of the day so you are ready for the next outing.

4) ON/OFF button - Press this switch momentarily to turn the unit on. When the unit is on, press and hold this button until the unit shuts off. Remember, the receiver/display unit has an auto-off feature, so if you forget to turn it off, the unit will turn itself off if no probe transmissions are received in a 30 minute period.

5) Backlight button - Press this switch momentarily to turn on the backlight. If the back light is on, press this switch again to turn the backlight off.

6) Backlight control - Press the > arrow button to increase the backlight intensity.
Press the < arrow key to decrease the backlight intensity.


The Depth Raider system includes everything necessary to install on your downrigger equipped boat. The system includes the following:

- Underwater sensor/transmitter probe unit
- Receiver/display unit
- Receiving antenna
- 25’ antenna-to-receiver coaxial cable with gold plated connectors
- 6’ DC power cable with in-line fuse holder and power plug
- 200’ coated downrigger cable
- Termination kit to connect coated downrigger cable to probe
- Rubberized electrical tape
- Cannonball drop leader kit



Key System Features:


Large, easy-to-read LCD display on receiver with user adjustable backlighting


Compact receiver/display unit can be mounted in a variety of locations


Receiver/display unit features automatic turn-off when no probe transmissions are detected in 30 minutes


Smallest underwater probe unit on the market


Ultra-low power electronics design extends battery life to over 225 hours typical


Probe automatically turns on when it enters the water


Electronics are encapsulated in epoxy to prevent damage from water should an O-ring fail


Double O-ring seal on battery cap prevents water entry into battery compartment


Precision speed and temperature sensing devices

To request information on this product please e-mail:  info@kell-labs.com