Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual

Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual & troubleshooting

Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual  & troubleshooting 1

Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder

Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual  & troubleshooting 2

Introduction to the Fish Finder

What’s in the Box

Please check if the following product and accessories are in the box before using this product. Write to [email protected] if anything is missing or broken.

  •  A sonar sensor
  •  A handheld host
  •  A charging cord for sonar sensor
  •  An antenna for the handheld host
  •  A Neck strap
  •  A copy of user manual

Fish Finder Display

  1.  The handheld host use 4*AAA alkaline batteries (not include).Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual  & troubleshooting 3
  2.  There is one charging cord for the sonar sensor in the package. When the sensor is charging, the indicator light is red. The light will turn off if the sensor is fully charged.Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual  & troubleshooting 4
  3.  When the sensor is out of water, it is off and will not connect with the host, and the sensor’s Battery Indicator on the screen is incorrect. If you would like to check the sensor’s battery status from the screen, you need to put the sensor in water and install the antenna of the handheld host first.

Note: The cover of the sensor should be removed when charging, and should NOT be removed when working.


  1.  The host is not waterproof. Please do not submerge it in water. If water splashes on the host, please dry it immediately.
  2.  The sensor is supposed to float on water when working. Please don’t drag it into water bottom, or submerge and hold the whole sensor under water.
  3.  Its reading might be interfered with other high power sonar device close to your sonar sensor.
  4.  If water wave is too strong, please protect the sensor from crashing into rock. Otherwise it will cause irreparable damage to the sensor.
  5.  The fish finder will only operate properly in open water that is deeper than 2.6 feet.

How to Use the Sonar Sensor

How the sonar fish finder works

Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual  & troubleshooting 5

  1. The system uses sonar to locate and define structure, bottom contour, and depth directly below the sensor. It transmits sound pulse from the sensor, and then measures the time it takes for  the echoes to return to the sensor. Different objects in water echo the pulse at a different intensity. The built-in computer then organizes all of this information and shows it on the display screen.
  2.  The first column of fish indicators on the right of the screen shows the most current information. This icon is then moved to the left as a new reading is displayed. This motion in no way reflects actual movement of the fish.

Sonar sensor

How to turn on the sensor

There are 2 pins on the sonar bottom, which are the automatic switch of the sensor. The sensor will turn on only when you toss it in water. Once these 2 pins touch water, the sonar sensor will automatically turn on, connect with the host (please install the antenna of the host in advance), and start working. Note: Please dry water on the sensor after it is out of water. Otherwise the sensor might keep working.

Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual  & troubleshooting 6

How to use the sensorLetuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual  & troubleshooting 7

There are 2 small holes on the sensor. Tether the sensor with fishing line (not included) and toss it into water. You can use a rod to guide the sensor to a fix spot or use a remote-controlled boat to send the sensor to the fishing spot.

Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual  & troubleshooting 8

Application methods

  1.  Toss the sensor into water, drag it at a very slowly and stable speed. It will display information of water under the sensor, including water depth, bottom contour, and fish location.
  2.  Toss the sensor into water, guide it to a desirable position and let it undisturbed. It will float on water and monitor submarine news in a real-time method. Information will be automatically updated on the screen once fish enter the sensor detection range.

Setting of the Handheld Host

Keys on the host/display unit

Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual  & troubleshooting 9

  • Power Key — Press and hold the power key for 2 seconds, the display unit will power on. The display unit starts working. Press and hold the power key for 3 seconds, the display unit will power off.
  • Menu Key — Press this key to enter menu setting. There are 3 menu pages. Press Menu Key to enter the 1st menu page, press the Menu Key again to enter next menu page, and press Menu Key once again, to enter the 3rd menu page.
  • Exit Key — Press this key to exit menu or preference setting
  • Zoom Key — Press this key to magnify the image display.
  • Direction Key — Press the direction key to select and adjust the preference you would like to set.

Feature Setup/Preference Setting

Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual  & troubleshooting 10

There are 20 levels of sensitivity setting for user to choose from. It greatly depends on the clarity and depth of the water. Very clear water allows for a moderate sensitivity setting. Conversely, dirty water requires a higher sensitivity setting to target detail but will increase the irritating false readings. Targeting fish in deep water generally requires higher sensitivity, especially in dirty water. Otherwise, the sensitivity can be lowered in shallow water. Salt and brackish water also require a comparatively higher sensitivity setting. As the sensitivity is enhanced, smaller details show on the screen (but trash & debris might be detected as fish)

Operation guide
Press Menu Key to enter into the 1st menu page. Press up/down Direction Key to select the “SENSITIVITY”. When “SENSITIVITY” is selected, press left/right Direction Key to adjust the value (5% -100%) of this feature. Press up/down direction key to select other feature setting or press “ECS” to exit feature setting.

Fish Alarm
An alarm sounds when a group of fish is detected. The alarm feature can be turn off if you prefer quiet fishing.

Depth Alarm
The depth alarm can be turned off or range from 2M/7Ft to 50M/164Ft. When the detected water depth is equal or less than setting value of depth alarm, it will alarm. This feature is mainly used for ships. Users can set a depth alarm value according to actual needs to avoid hitting rocks. It is also a great function for sea fishing users looking for reefs. It helps to find good fishing spots.

Setting the backlight to be highest will greatly reduce the battery life. It is suggested to adjust the backlight at a proper number.

Chart Speed
The fish finder has ten levels (10-100%) of chart speed for the user to choose from. 10% chart speed is the slowest while the 100% is the fastest. Generally it is suggested to set the chart speed highest, so that you can get update of underwater information in time.

Unit Set
Units of measure for depth and temperature can be set as M/℃ or Ft/℉.

Depth Range
This feature has 6 depth ranges (AUTO, 10 Ft, 20 Ft, 30 Ft, 60 Ft, 120 Ft,). Depth range setting is used to adjust the bottom display width. For example, the actual water depth is 10 Ft, and the depth range is 20 Ft, the display width of the bottom will be 50% of the screen. User can adjust the depth range according to the actual water depth. Recommended depth range is set to be larger than and closest to the actual depth of water, in order to obtain the best display. Or it can be set to be AUTO.

Mode Set
Simulator mode helps beginner to learn readings on the display quickly.

Noise Filter
Noise Filter Setting is used for filtering sonar noise. The fish finder has 4 Noise Filtering levels (off, low, medium, high) for user to choose from. Choose different value according to the actual situation.

Storage of the Fish Finder

  1. Remove batteries from the display unit before storing to prevent battery leakage and corrosion.
  2.  The display unit is not waterproof. Please do not submerge or spray the screen with water.
  3.  Clean the sensor with fresh water and dry off.
  4.  Keep the sensor and the display unit in dry condition after use. Don’t place them in wet condition. Don’t place the sensor in metal container.
  5.  Never leave the fish finder in temperatures over 113°Fahrenheit (45° Celsius) as the extreme temperatures can damage the electronic components.
  6.  Keep the unit in temperatures above 14° Fahrenheit

Product Specification


  • Display Size: 52 x 39 mm
  • Display resolution: 240*320
  • Backlight: LED backlight

 Sonar & Radio

  • Depth Range: 2.6-118Ft/0.8-36M
  • Maximum Wireless Distance: 131FT/40M.
  • Sonar Frequency: 125KHZ
  • Sonar Beam Angle: 90 degree
  • Radio Frequency:2.4GHz
  • Operational Temperature: 14°F to 113°F(-10°C to 45°C)

Power Supply

  • Display unit: 4*AAA batteries (not included)
  • Sensor: Built in Polymer battery 3.7V

Frequently Asked Questions

It will not power on
Please make sure the 4*AAA batteries are installed correctly. Press and hold the power key for 2 seconds to turn on the display unit. If the display unit does not turn on under properly operation, please send your order number and fish finder issue to [email protected] for help.

Depth reading is “—” or incorrect

  1.  Other high power sonar fish finder close to the fish finder will interfere with the fish finder’s sonar and cause incorrect reading.
  2.  Please make sure the sonar is not out of power andit is floats on water in peace. If water wave is too strong, the depth reading might be incorrect.
  3.  Please make sure the water is within the depth range of 2.6Ft/0.8M to 118Ft/36M.
  4.  Suspended matter, muddy water, or extremely heavy vegetation may also confuse the sonar and cause misreading of depth.
  5.  Oil, dirt would adhere to the surface of the sensor and will affect the sonar sensor’s performance. Please make sure the surface of the sensor is clean.
  6.  Please make sure the sensor is vertically downward.
  7.  Adjust the sensitivity of the fish finder to be higher or
  8. lower.  Please make sure the temperature is above -10℃/14 ℉.
  9.  When fishing on ice or “shooting-through” the hull of a boat, depth reading might be unstable or displays as “—” if there is bubble under the sonar. Sonar will not travel through air. So the smallest air bubble between the sensor and the water will cause the unit to operate incorrectly.

It shows fish / It is not working in my pool
The fish finder will NOT function properly in a bath tub, swimming pool, bucket, or any body of water that has hard sides. It must be used in an open body of water to function properly.

Is the display waterproof?
The display unit is not waterproof. Do NOT submerge or spray the fish finder screen with water.

How long is the battery duration (fully charged)?
It depends on the backlight level you set and the capacity of the batteries you use.. It usually lasts about 4-6 hours in continuous use. Reduce the backlight level to extend battery life.

There are fish in water, but the fish finder shows nothing. 
The fish finder can only detect fish in detectable area (105 degrees beam angle under the sensor). And the fish finder will not detect any objects that are closer than 2 feet from the sensor. It is the blind area of sonar. If you’re fishing in water that is less than 3 feet deep, it is recommended to discontinue use of the fish finder. Besides that, the fish finder might not be able to distinguish fish from weeds if fish swimming too close to the water bottom.

False fish indications
Tall weed may cause false fish indications. If weeds grow taller than 50% of the total water depth, the sonar will mistake it for fish. Trash & debris may also result in false fish indications. Adjusting the sensitivity setting to the lowest level may reduce these false readings, but if they do not go away, it is suggested that you discontinue use of the fish finder under these conditions.

Will it work for ice fishing
It can work for ice fishing. It is suggested to drill hole on ice and put the sensor into the water.

How far do you cast it out?
The maximum wireless distance range is about 131FT/40M.

Does it show the size of fish?
It displays fish symbol by 3 different fish sizes-small, median, big.

Can this be mounted to the boat?
There are 2 holes in the sensor to tether with fishing line. You can mount it to your boat. Please make sure the sensor bottom is in water and the sensor is floating vertically downward.

Warranty and After-sale Support

This fish finder is eligible for a 2-year warranty. To get a 2-year warranty for your fish finder, please register your product on our brand website www.venterior.com, or just send your order number to [email protected] directly (we will register it in our system for you).

After-sale Support
If you are not satisfied with the fish finder or would like to get any of our technical support, please feel free to send your questions or the fish finder issue to [email protected]. We are always happy to assist you.


FCC Statement
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:

  1.  this device may not cause harmful interference, and
  2.  this device must accept any interference received, including interference that may cause undesired operation.

CAUTION: Modification or changes to this equipment not expressly approved by Radio Systems Corporation may void the user’s authority to operate the equipment.

NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a specific installation. If interference does occur to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

  •  Reorient or relocate the receiving antenna.
  •  Increase the separation between the equipment andthe receiver.
  •  Connect the equipment to an outlet on a circuit different from that to which the receiver is connected.
  •  Consult customer care, the dealer, or an experienced radio/TV technician for help.


Setting up Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual is easy with these step-by-step instructions. Follow the steps are you are set-up in no time.

Using Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual is simple by using this manual. Follow the instructions one by one and everything will be fine

Is Letuo E Commerce VT-FF004E Venterior Wireless Fish Finder User Manual stuck or not working properly? By resetting it you can set it back to the standard settings and everything should be back to normal. This works in many cases when problems arise.

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