echo fish finder

FP621S Fish Finder For Small Boat | 6-Inch | 300-600W Dual-Frequency | DSP Technology

FP621S 6-Inch Fish Finder for Small Boats – DSP Digital Signal Processing with Independent Dual-Frequency Gain Control

For small boat owners who need professional fish finding capability without a large display or complex installation, the FP621S delivers 300-600W of dual-frequency power (50 & 200kHz) in a compact 6-inch package. Advanced high-precision DSP digital signal processing technology provides low blind zone operation and high-resolution echo display – keeping every fish visible even in shallow water where small boats typically fish.

Why Small Boat Owners Choose the FP621S

DSP digital signal processing – Advanced high-precision DSP technology processes sonar returns with full high-speed sampling. Low blind zone performance means you see fish immediately below the transducer, not after a 2-3 meter gap common with basic fish finders.

Independent dual-frequency gain control – Adjust gain separately for 50kHz and 200kHz frequencies. This allows you to optimize each frequency for current water conditions, depth, and bottom composition. No compromise between wide search and detailed bottom view.

Compact 6-inch professional display – Bright, high-contrast screen with adjustable brightness adjustment works in direct sunlight and at night. Multiple color palettes and background modes reduce eye fatigue during long days on the water.

SD card data storage and playback – Record sonar data to SD card during your fishing trip. Play back at home to study bottom structure and fish patterns. Also use SD card for fast program upgrades.

 

Display Modes for Every Fishing Situation

Dual frequency display – View 50kHz and 200kHz sonar returns simultaneously on the split screen. Compare wide search beam with detailed narrow beam in real time.

A-mode – Traditional analog-style echo display. Shows raw sonar signal strength and depth. Useful for experienced anglers who prefer interpreting unprocessed returns.

Zoom mode– Three zoom options available:

Auto zoom – Automatically keeps bottom in the zoom window as depth changes

Manual zoom – Select any depth range to magnify and examine detail

Bottom lock – Locks display to follow bottom contour. Shows fish and structure immediately above the seafloor

7 Scroll Speed Options

Control how quickly sonar history scrolls across the screen:

Stop – Freeze display for detailed examination

1/8, 1/4, 1/2 – Slower scroll for calm conditions or drift fishing

1/1 – Standard speed for most fishing

2/1, 3/1 – Faster scroll for higher boat speeds or quick bottom assessment

Color Display Options

Echo colors – 5 color palettes to choose from. Select the scheme that provides best contrast for your lighting conditions and personal preference.

Background colors  – Black or blue background options. Black provides highest contrast for daylight. Blue reduces eye strain during night fishing.

Alarms for Small Boat Safety

Voltage alarm – Monitors your boat's electrical system. Warns before low voltage affects fish finder performance or leaves you unable to start the engine.

Depth alarm – Set minimum depth for shallow water alert. Critical for small boats navigating unfamiliar channels or tidal flats.

Water temperature alarm (with optional temp transducer) – Alert when water temperature enters target species range.

Data Integration – NMEA0183 Standard

Input sentences (IEC61162-1 NMEA0183) – RMC and GLL from your GPS/chart plotter. Provides position and speed data for correlating sonar returns with GPS waypoints.

Output sentences (IEC61162-1 NMEA0183) – DPT and DBT output when RMC/GLL input is active. Feeds depth data to autopilots, radar systems, and network displays.

Serial port for printing – Compatible with DPU-414 printer. Print sonar screenshots for fishing logs or captain's records.

Built-in Signal Simulator / Test Mode

Professional facility for echo sounder and fish finder signal testing. Precise模拟回波信号 (simulated echo signals) of sea bottom and fish schools. Test and demonstrate unit operation without being on the water. Also useful for installation verification and training new crew members.

Temperature Sensor – Built Into Transducer

The temperature sensor is included in the transducer, providing water temperature reading at the same location as your sonar data. No separate temp probe or installation required. Critical for locating species that prefer specific temperature ranges.

Small Boat Friendly Design

Simple installation – Straightforward setup designed for small boat owners. No professional installation required for basic mounting and wiring.

Durable construction – Built to withstand marine spray, sun exposure, and vibrations common on smaller craft moving at planing speeds.

Memory storage – Built-in memory stores sonar settings when the unit is turned off. Your preferred gain, range, zoom, and color settings are ready when you power up.

What's Included in the FP621S Package

FP621S 6-inch display unit

Dual-frequency transducer (50/200kHz) with integrated temperature sensor

Power cable (DC 24V, accepts 11-35V)

Mounting bracket and hardware

Documentation and installation manual

Optional: SD card for data storage and playback

Technical parameters：

Model	FP621S
TX Frequency	50&200KHz
Output Power	300W-600W
TXRate	0.12~3.0ms
Accuracy	0.1m
Sensitivity	-95dBm
Alarm	Depth,Voltage,Temperature
Language	Simplified Chinese, English, Traditional Chinese
Display Unit
Display Mode	Dual frequency,Single frequency (high or low freq.), A-scope, Zoom(high or low freq.)
Expansion Mode	Auto Expansion,Manual Zoom,Bottom Lock
TXRate	7 steps(stop,1/8,1/4,1/2,1/1,2/1,3/1)
Color	Echo color:5 color schemes Background color：black, blue
Interface
Input data	IEC61162-1(NMEA0183)RMC, GLL
Output data	IEC61162-1(NMEA0183)DPT, DBT(After GLL and RMC Input)
Serial port to print	Suitable for printer DPU-414
Power Supply	DC 24V(11-35V)
Environmental
Operating temperature	-10℃~+40℃ Compliance with IEC60945 standard
Working humidity	10~90%

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