Garmin GT20-TM Transducer - ClearVu and Traditional Sonar

Our review of the Garmin GT20-TM Transducer finds it well suited for shallow water anglers who want reliable traditional 77/200 kHz sonar plus CHIRP-style ClearVu scanning at 455/800 kHz. The single biggest reason to buy is the consistent target separation and clear images of structure and fish beneath the boat, delivered from a transom or trolling motor mount with a 20 ft cable and built-in fast-response temperature sensor. For anglers who need a compact, easy-to-install transducer rated 500 W and capable of both traditional arches and detailed ClearVu imagery, this model hits the mark.

Key Features

• Dual-frequency sonar: Traditional 77/200 kHz provides classic fish arches and reliable depth readings for general use.
• ClearVu scanning: 455/800 kHz ClearVu gives a more detailed, photo-like view of structure and fish up to the specified depth limits.
• Transom and trolling motor mounts: Includes hardware to mount on a transom or a trolling motor, offering installation flexibility for different boats.
• 20 ft cable with temperature sensor: The long cable and built-in fast-response temperature sensor let users place the transducer for best signal and monitor water temperature accurately.
• 500 W power rating: Adequate power for clear returns in shallow to moderate depth scenarios common to inshore and lake anglers.

Who It's For

The GT20-TM is aimed at recreational anglers and weekend boaters who fish in shallow to moderate depths and want both traditional sonar and higher-resolution ClearVu scanning in a single, easy-to-install package. It is especially good for those using transom-mounted setups or who have trolling motors and need the option to switch mounting styles without buying a separate unit.

Serious deepwater anglers who require maximum depth performance beyond the ClearVu 750 ft or need specialized thru-hull installations should consider other models. Also, users who need an 8-pin plugless interface or a different cable length should confirm compatibility with their sonar head unit before purchase.

Pros & Cons

Pros

• ClearVu 455/800 kHz delivers detailed images of structure and fish for confident target ID.
• Included transom and trolling motor mounts make installation flexible and straightforward.
• Good build quality and perceived value, with a 20 ft cable and temperature sensor included.

Cons

• Fit receives mixed feedback, so installation may require adjustments on some hull shapes or electronics setups.
• ClearVu depth is limited compared with deepwater-dedicated transducers.

Specifications

Our Verdict

The Garmin GT20-TM is a practical choice for anglers who want both traditional 77/200 kHz sonar and higher-resolution 455/800 kHz ClearVu scanning in one unit, with flexible mounting and a useful 20 ft cable. It offers solid build quality and value for typical inshore and lake use, though those needing extreme depth performance or guaranteed fit for unique hulls should evaluate compatibility first.

Frequently Asked Questions

Can this transducer be mounted on a trolling motor?
Yes. The GT20-TM ships with hardware for transom and trolling motor installation so you can choose the mounting that fits your boat.

What depths will ClearVu and traditional sonar reach?
Traditional sonar is rated to about 1,900 ft while ClearVu scanning is rated to roughly 750 ft, making it best for shallow to moderate depth fishing.

Does the cable include a temperature sensor?
Yes. The 20 ft cable has a built-in fast-response temperature sensor for reliable water temperature readings.