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GARMIN GSD 20 Remote Sounder

Discontinued. Replaced by Garmin GSD 22 Remote Sounder >>

The GSD 20 is a remote, black-box sounder that transmits 500 watts at 50/200kHz. It is designed for use with the following units - to provide SONAR capabililites!

It is compatible with GPSMAP 276C, GPSMAP 296, GPSMAP 376, GPSMAP 378, GPSMAP 396, GPSMAP 478 and GPSMAP 496

[Also for Discontinued units: GPSMAP 3005C, GPSMAP 3006C, GPSMAP 3010C, GPSMAP 2006/2006C, GPSMAP 2010/2010C, GPSMAP 182/182C, GPSMAP 232]

The sounder module sends data serially in a Garmin proprietary format to up to two units on board. When viewed on Garmin chartplotters, you'll see full-featured sounder displays in either split- or full-screen presentations. Features include auto-ranging, 2X and 4X auto and manual zoom, optional fish symbols and See-Thru? technology, which separates fish from thermoclines and structure.

Please Note: This product does not include a transducer. Garmin offers a complete selection of transducers to be purchased separately as accessories.

• Great for dual-helm boats; allows you to view and control sonar on one or two chartplotters
• External mounting to allow shorter transducer cable length on large boats
• 4,000 watts transmit power peak-to-peak (500 watts RMS)
• 1,500 foot max depth*
• Dual frequency 50/200 kHz (40/10) for shallow or deep-water performance
• Display options - auto ranging, 2X and 4X auto and manual zoom, 3 fish symbol sizes, adjustment bar
• Alarms - deep water, shallow water, 3 size fish, low battery
• Transducer auto sense - automatically displays speed and temperature data without menus
• See-Thru? technology - shows weak/strong returns simultaneously
• Depth Control Gain (DCG?) - automatically adjusts fishfinder sensitivity according to depth
• Size - just 4.75" W x 6.75" L x 2" H
• Waterproof to IPX-7 standards
• Easy installation
• Comes standard with a 30-foot cable and mounting kit
Numerous transducer options including transom, plastic or bronze thru-hull

* Depth capacity is dependent on water salinity, bottom type, and other water conditions
Updates & Downloads


Standard purchase includes: GSD 20, 30 ft power/data cable, mounting kit and installation guide (transducer not included; click here for transducer options)



GSD 20 Remote Sounder with 30 ft power/data cable
Note: A Transducer is sold separately

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