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Humminbird HELIX 7 CHIRP MEGA SI GPS G3 Navionics+

ProductDisplay SizeSonarDepth

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Mega DI,
Mega SI,
1,200' 2D
125' DI,
125' SI,
AC Live,

The Humminbird HELIX 7 CHIRP MEGA SI GPS G3 Navionics+ basically offers the same transducer and head unit as the HELIX 7 CHIRP MEGA SI GPS G3, but includes a Navionics+ card. The unit itself also has its own built-in Humminbird Basemaps. For reference, this is the Humminbird fish finder part number 410950-1NAV.

Key Features and Specifications

  • Display: 7-inch diagonal, 800H x 480V pixel resolution, WVGA 16-bit color TFT, with LED backlight
  • Sonar: Dual Spectrum CHIRP, CHIRP Mega Side Imaging, Mega Down Imaging
  • Transducer: Transom XNT 9 HW MSI 150 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 / 75°
    Side Imaging: 440-500 kHz / 86° / 480 ft (146 m) side-to-side
    Mega Side Imaging: 1075-1150 kHz / 86° / 250 ft (76 m) side-to-side
  • Depth Capability (with the included transducer):
    Dual Spectrum CHIRP: 1,200 ft (365 m)
    Down Imaging: 125 ft (38 m)
    Mega Down Imaging: 75 ft (23 m)
    Side Imaging: 125 ft (38 m)
    Mega Side Imaging: 75 ft (23 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 first aspect to mention here is that the HELIX 410950-1NAV includes the XNT 9 HW MSI 150 T transducer as opposed to the MEGA SI+ unit which comes with the superior XM 9 HW MSI T. But nonetheless, this transducer is capable of MEGA Side Imaging and MEGA Down Imaging sonar, and also supports the Dual Spectrum CHIRP sonar. It is a plastic transducer, it integrates a temperature sensor, includes a transom mount and has 20 ft (6 m) of cable.

For Side Imaging, the transducer uses two side beams which are oval-shaped, with a coverage of approx. 86°. They offer total side-to-side coverage of 250 ft (76 m) when using the Mega SI mode, and a total side-to-side coverage of 480 ft (146 m) when using the regula Side Imaging mode. Also, in case you’re wondering, the CHIRP range is 440-500 kHz for regular SI, and 1075-1150 kHz for Mega SI.

For Down Imaging, the unit also offers regular and Mega DI modes. The beam coverage is 75° for both regular DI and Mega DI. However, the depth capability of the Down Imaging mode isn’t as great as for the XNT 9 HW MDI 75 T which is included with the HELIX 7 CHIRP Mega DI GPS G3 Nav+. Just as for Side Imaging, it can only reach 125 ft (38 m) when using regular DI, and 75 ft (22 m) when using Mega DI.

Finally, for Dual Spectrum CHIRP, the included XNT 9 HW MSI 150 T transducer makes available three sonar modes. These are Narrow Mode (180-240 kHz), Wide Mode (140-200 kHz), and Full Mode (150-220 kHz). The transducer beams are conical for the 2D sonar, not oval as for SI and DI. Their coverage is 42° when using the Wide or Full Mode, and 25° for the Narrow Mode. Also, for the Dual Spectrum CHIRP sonar, the transducer offers the greatest depth penetration; it can reach depths up to 1,200 ft (365 m).

Nonetheless, the unit offers a wide array of standard sonar features and functions. The list includes SwitchFire, Circular Flasher mode, Real Time Sonar, Selective Fish ID, Bottom Lock, Fish Alarm, Depth Alarm, and more. Sonar Recording and Sonar Rewind are also available, but in order to use these features, you will have to remove the Navionics+ card from the unit and use a blank data card. The unit cannot save the recording in its memory.

Navigation features

As we’ve mentioned above, this Humminbird fish finder bundle includes a Navionics+ charts 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. Plus, it offers access to the SonarChart feature, but even if you won’t be using the Navionic+ chart, the unit also has its own depth contour mapping function which is the AutoChart Live.

Nonetheless, the unit has its own built-in charts – the Humminbird Basemap. These charts cover 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. So, you can either use the Navionics+ platform or the Humminbird Basemap chart platform. Of course, the unit is also compatible with SmartStrike fishing charts, LakeMaster charts, LakeMaster Plus charts, and the Navionics Platinum+ charts.

The HELIX 7 CHIRP MEGA SI GPS G3 Nav+ has a built-in GPS receiver. Its operating frequency is not specified, but it is probably 5 Hz, which means it can provide position updates of at least 5 times per second. The unit has a GPS speed function which means it can calculate and display the speed of the boat based on the GPS data. It can provide position augmentation via WAAS, MSAS, and EGNOS. It also can store up to 2,750 waypoints in its memory, 45 routes, and 50 tracks; each plotted track can have up to 20,000 points.

It’s important to mention that since it’s only a G3 unit, it does not support Radar, 360 Imaging sonar, or other instruments which require an Ethernet connection, as the unit does not have Ethernet. However, it can support external GPS and AIS units.

Control unit features

The HELIX 7 CHIRP MSI GPS G3 Nav+ features an LCD display with a 7-inch diagonal and a pixel matrix of 800H x 480V. It has a 16-bit color range and LED backlight which provides excellent readability in direct sunlight and from sharp angles (~70°).

The unit has an IPX7 waterproof rating. This means it can support incidental water exposure such as splashes or rain, and even full immersions in freshwater up to 1 meter.

The box includes the standard Gimbal mount. The in-dash mounting kit and the unit cover are not included (available separately).

The unit is keypad operated. It has a highly intuitive, user-friendly interface. It does not have cross-touch technology, though, does not have Bluetooth technology and is not compatible with the RC2 remote control.

Since it’s a G3 unit and not a G3N, it does not support Ethernet or 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 Pros

  • Dual Spectrum CHIRP sonar;
  • CHIRP Mega Down Imaging and regular CHIRP Down Imaging sonar;
  • CHIRP Mega Side Imaging and regular CHIRP Side Imaging sonar;
  • XNT 9 HW MSI 150 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+ chart card included;
  • AutoChart Live;
  • Supports Navionics+, Navionics Platinum, LakeMaster Plus, and SmartStrike charts;
  • Trackplotting, routes and waypoints functions;
  • 7-inch 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.

Bottom Line

The Humminbird HELIX 7 CHIRP MSI GPS G3 Nav+ is a fish finder and chartplotter combo, offering 2D CHIRP sonar, MEGA SI, MEGA DI, basemap and Navionics+ charts, and AC Live. It includes the XNT 9 HW MSI 150 T transducer. It’s a mid-range unit, great for a wide array of boats, perfect for both in-land and blue water fishing.

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