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Humminbird HELIX 7 CHIRP MEGA DI GPS G3 Navionics+

ProductDisplay SizeSonarDepth

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1,200' 2D
350' DI,
125' MDI,


AC Live

This Humminbird HELIX package basically the same as the HELIX 7 CHIRP MEGA DI GPS G3 that we’ve already reviewed here. However, the box also includes a Navionics+ card for out of the box map coverage. For reference, this is the Humminbird fish finder part number 410940-1NAV.

Technical Details and Specifications

  • Display: 7″ diagonal, 800H x 480V pixel resolution, WVGA 16-bit color TFT, with LED backlight
  • Sonar: Dual Spectrum CHIRP, CHIRP Mega Down Imaging
  • Transducer: Transom XNT 9 HW MDI 75 T
  • Frequency and Coverage:
    • 2D Narrow Mode: 180-240 kHz / 25°
    • 2D Wide mode: 140-200 kHz / 42°
    • 2D Full mode: 150-220 kHz (adjustable) / 42°
    • Down Imaging: 440-500 kHz / 75°
    • Mega Down Imaging: 1075-1150 kHz / 45°
  • Depth Capability (with the included transducer):
    • Dual Spectrum CHIRP: 1,200 ft (365 m)
    • Down Imaging: 350 ft (106 m)
    • Mega Down Imaging: 125 ft (38 m)
  • Power Output: 500 Watts (RMS)
  • Power Input: 10.8-20V DC
  • Power Draw: 800 mA
  • GPS: Internal
  • Cartography: Humminbird Basemap, Navionics+
  • Routes, Waypoints, Tracks: 45; 2,750; 50 (20,000 points each)

Sonar and transducer

The HELIX 7 CHIRP MEGA DI GPS G3 unit supports multiple base sonar frequencies, including 50/83/200/455 kHz. It has two types of sonar, these being Dual Spectrum CHIRP and Mega Down Imaging. Of course, the unit can also use regular Down Imaging.

The box includes the new XNT 9 HW MDI 75 T transducer. This is basically High CHIRP transducer and supports both sonar types of the unit (2D and MDI). It features a transom mount, 20 feet (6 meters) of cable, and an internal temperature sensor.

For Dual Spectrum CHIRP, the transducer uses two conical beams. Their coverage is 42° for the unit’s Wide Mode (140-200 kHz) and Full Mode (150-220 kHz), and 25° when using Narrow Mode (180-240 kHz). For Wide Mode and Narrow Mode, the CHIRP frequency intervals are fixed, while for Full Mode, the interval is adjustable, the 150-220 kHz being only the default value.

With the included transducer, this Humminbird fish finder system can reach depths up to 1,200 ft (365 m) when using the 2D sonar. However, with a 50 kHz capable transducer, this unit can scan depths up to 3,500 ft (1066 m).

For Down Imaging, the transducer uses oval beams. When using the regular Down Imaging mode (at 440-500 kHz), the beam offers a coverage of approx. 75°. Conversely, for the MEGA DI mode (at 1075-1150 kHz) the beam angle is 45°. Also, with the included transducer, this fish finder system can scan depths up to 350 ft (106 m) when using Down Imaging, and up to 125 ft (38 m) when using MEGA Down Imaging.

Needless to say, the unit offers all the standard sonar features that the previous similar units had. It has the Switchfire function, Selective Fish ID, Bottom Lock, Real Time Sonar (RTS or A-Scope), Sonar Recording, Screen Snapshot, Depth Alarm, Fish Alarm, and more.

Navigation features

To begin with, this Humminbird unit is equipped with an internal GPS receiver. It offers augmentation possibilities via WAAS, EGNOS, and MSAS. It also has a GPS speed function so it can calculate the speed of your boat based on the GPS feed. The unit can store up to 2,750 waypoints in its memory, offering various icons for them so you can personalize them better. It can also save up to 45 routes and 50 plotted tracks with up to 20,000 plots per track.

In terms of charts, the unit is preloaded with the Humminbird Basemap. This chart platform covers more than 10,000 U.S lakes with 1 ft depth contours, and also provide coverage for coastal waters, showing depth markers, buoys, hazards, marinas, nav-aids, and various other points of interest.

However, the box also includes a Navionics+ card. This chart platform covers more than 21,000 lakes and bodies of water in North America. It also provides Nautical Chart guides, Sonar Chart HD bathymetry mapping and free Community Edits for a full year.

Navionics+ gives you access to SonarChart. However, this Humminbird unit has its own chart recording application – AutoChart Live. It uses the GPS positioning information and the 2D sonar information to reveal and draw the depth contours of your lake on the map. Therefore, if the current charts do not offer satisfying contours for your lake, you can always map it yourself. The unit can store up to 8 hours of contour recording, but you can expand it with a Zero Lines chart card.

In terms of chart compatibility, the Humminbird HELIX 7 CHIRP MEGA DI GPS G3 offers support for several other types of charts. For example, it is compatible with LakeMaster and LakeMaster Plus charts, Navionics Platinum+, and SmartStrike fishing charts.

Last but not least, the unit supports AIS and GPS heading sensor units. However, since it’s not an Ethernet unit, it does not support Radar or Minn Kota i-Pilot Link. It also does not support 360 Imaging sonar.

Control unit features

The Humminbird HELIX 7 CHIRP MDI GPS G3 features a 7″ diagonal display with a pixel resolution of 800H x 480V. Evidently, it’s a color display, with a 16-bit color range, WVGA type. It has adjustable LED backlight, offering excellent brightness and visibility even in direct sunlight.

The unit is keypad operated; it does not have touchscreen technology like the SOLIX units, for example. It is IPX7 waterproof rated. This means it can support incidental water exposure such as splashes or rain, and even full immersions in freshwater up to 1m.

Like all the other G3 units, this one does not have Ethernet and does not support NMEA 2000. It has three connectors, one for the power cable, one for the transducer, and one for the communications cable (NMEA 0183). It also has a microSD card reader with one slot. Therefore, you can add a microSD card with better charts, or update the unit’s internal software via data microSD card.

The box includes the standard Gimbal mount. The in-dash mount kit and the unit cover are optional.

The Pros

  • Dual Spectrum CHIRP sonar;
  • CHIRP Mega Down Imaging and regular CHIRP Down Imaging sonar;
  • XNT 9 HW MDI 75 T transducer included;
  • Depth capability up to 1,200 ft with the included transducer;
  • Multiple sonar functions available, such as RTS, Bottom Lock, Selective Fish ID+, Alarms, SwitchFire etc;
  • Sonar Recording and Screen Snapshot functions;
  • Precision internal GPS;
  • Humminbird Basemap chart platform built-in;
  • Navionics+ charts card included;
  • AutoChart Live;
  • Supports Navionics+, Navionics Platinum, LakeMaster Plus, and SmartStrike charts;
  • Trackplotting, routes and waypoints functions;
  • 7″ display, 800 x 480 resolution, 16-bit color display, with LED backlight, providing clear images, easy to read even in direct sunlight;
  • IPX7 waterproof;
  • NMEA 0183 output;
  • Supports AIS an GPS heading sensors;
  • MicroSD card reader (1 slot);
  • Upgradeable internal software;
  • Gimbal mount included;
  • Fairly easy to install.

The Cons

  • The in-dash mounting kit is not included;
  • A unit cover is not included;
  • No trolling mount for the transducer (only transom mount).


The Humminbird HELIX 7 CHIRP MDI GPS G3 NAV+ offers Dual Spectrum CHIRP and Mega DI sonar, GPS, the Humminbird Basemap charts, and AutoChart Live. It also includes the standard XNT 9 HW MDI 75 T transducer and a Navionics+ card. It’s a mid-range fish finder and chartplotter, great for a wide array of boats, for both freshwater and saltwater.

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