Humminbird Helix 7 Review: G4N MEGA Side Imaging Kit or Control Head Only
Our Humminbird HELIX 7 review compares the G4N MEGA SI kit and the MEGA DI control head only: imaging, maps, networking, and who should skip each.
Updated November 1, 2026
The Humminbird HELIX 7 is a family, not one fish finder, so the first decision is which version to buy. In the listings we reviewed, two HELIX 7 G4N units stand out. The HELIX 7 G4N MEGA Side Imaging kit (411940-1) ships with an XNT 9 HW MSI 150 T transducer and names MEGA Side and MEGA Down Imaging. The HELIX 7 G4N MEGA Down Imaging unit (411640-1CHO) is a control head only, with no transducer in the box. Both share Dual Spectrum CHIRP sonar, GPS, the Humminbird Basemap, AutoChart Live, and networking with Ethernet, Bluetooth, and NMEA 2000, according to their Amazon listings.
Our short answer: if you are buying your first imaging unit, the MEGA SI kit is the simpler choice, because its listing names side and down imaging with a transducer included. Buy the control head only when you already own a compatible transducer or plan to add one, such as a second display at the bow. This Humminbird HELIX 7 review is research-based. Humminbird lists the HELIX 7 CHIRP MEGA SI GPS G4N and MEGA DI GPS G4N among its current HELIX products, though the MEGA SI kit’s model number (411940-1) does not appear in Humminbird’s support documents. Screen, power, and imaging figures come from Humminbird’s HELIX operations manual and help center, and the rest from the Amazon listings.
This guide is general product information, not repair or electrical safety advice. Follow the installation, wiring, and charging instructions in your product’s manual, stop using any battery, charger, or electronics that overheat, swell, or smell of burning, and contact the manufacturer.
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Humminbird HELIX 7 G4N MEGA SI with Transducer
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Humminbird HELIX 7 G4N MEGA DI (Control Head Only)
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Humminbird HELIX 7 at a Glance
Figures marked (Humminbird) come from Humminbird’s HELIX manual; the rest come from each unit’s Amazon listing.
| Spec | HELIX 7 G4N MEGA SI with transducer (411940-1) | HELIX 7 G4N MEGA DI, control head only (411640-1CHO) |
|---|---|---|
| Imaging | MEGA Side Imaging to 125 ft on each side and MEGA Down Imaging to 75 ft below (Humminbird); the listing gives 125 ft for down imaging | MEGA Down Imaging to 125 ft below with the XNT 9 HW MDI 75 T (Humminbird; needs a transducer) |
| 2D sonar | Dual Spectrum CHIRP, 150 to 220 kHz (Humminbird), Wide and Narrow modes | Dual Spectrum CHIRP, 150 to 220 kHz (Humminbird), Wide and Narrow modes |
| Transducer in the box | XNT 9 HW MSI 150 T, transom mount | None |
| GPS and charts | GPS; Humminbird Basemap (10,000+ lakes, continental U.S. coastlines); LakeMaster, CoastMaster, Navionics compatible | Same as the MEGA SI kit |
| Live mapping | AutoChart Live, eight hours built-in recording; AutoChart Zero Line SD cards | Same as the MEGA SI kit |
| Networking | Ethernet ports, Bluetooth, NMEA 2000; Minn Kota and Cannon integration | Same as the MEGA SI kit |
| Display | 7 in, 1024 x 600 pixels, color TFT (Humminbird) | 7 in, 1024 x 600 pixels, color TFT (Humminbird) |
| Power input | 10 to 20 VDC; 3 A fuse (Humminbird) | 10 to 20 VDC; 3 A fuse (Humminbird) |
| In the box | Control head, power cable, transducer, mounting hardware, gimbal bracket | Control head, power cable, mounting hardware, gimbal bracket |
| Warranty | 1 year, manufacturer | 1 year, manufacturer |
| Not confirmed | 2D sonar depth rating (Humminbird’s manual and help center give different figures) | |
What We Like
- Side imaging in one box. The MEGA SI kit lists MEGA Side and Down Imaging with a transducer included, so there is nothing else to buy to see brush along a bank.
- Room for split views. A 7 in, 1024 x 600 pixel screen, per Humminbird, leaves more room for a map next to an imaging view than the 5 in HELIX 5.
- A basemap and live mapping. Both listings name the Humminbird Basemap and AutoChart Live, plus support for LakeMaster, CoastMaster, and Navionics charts.
- Networking. Ethernet, Bluetooth, and NMEA 2000 are named on both G4N listings, along with Minn Kota and Cannon integration.
What Could Be Better
- Easy to buy the wrong version. Titles look alike; only the feature list and box list of the MEGA DI unit say it is a control head only.
- Thin listings. Neither listing gives screen resolution, frequencies, or a 2D depth rating. Humminbird’s manual fills in the screen and frequencies, but Humminbird’s documents give different 2D depth figures.
- Weight is unclear. Both listings give 2.4 lb and the same dimensions, though only one box includes a transducer.
Which HELIX 7 to Buy: G4N, MEGA SI, or MEGA DI
Three parts of a HELIX 7 name, read against the listings, tell you most of what you need. On these listings, “G4N” goes with networking: both units here list Ethernet, Bluetooth, and NMEA 2000, and the G4 listing we saw names none of them. Humminbird’s naming guide confirms that an “N” marks networking models. Judging by the listings, “MEGA SI” and the “MSI” in the transducer name point to side imaging (the 411940-1 listing names MEGA Side and MEGA Down Imaging), and “MEGA DI” points to down imaging only. Then read the “Included Components” line: the 411940-1 lists an XNT 9 HW MSI 150 T transducer, while the 411640-1CHO lists none, and “CHO” in that model number, which Humminbird’s naming guide uses for “Transducer not included,” matches the “control head only” note in its feature list.
Other HELIX 7 listings exist. One is a HELIX 7 G4 MEGA SI kit (no “N”, and no networking named in its listing); we left it out of this review. If you see a HELIX 7 listing that does not name G4N, check the feature list for Ethernet and NMEA 2000 before you count on trolling motor integration.
Sonar and Imaging: What Each Version Shows
According to the Amazon listings, both units run Dual Spectrum CHIRP 2D sonar with a Wide Mode for coverage and a Narrow Mode for detailed scanning. That is the screen that draws fish arches and the bottom line. MEGA Down Imaging adds a picture-like view straight below the boat. Humminbird’s HELIX manual lists it to 125 ft with the XNT 9 HW MDI 75 T transducer used with the control head, but to 75 ft with the XNT 9 HW MSI 150 T in the 411940-1 kit, which adds MEGA Side Imaging out to 125 ft on each side. The kit’s Amazon listing gives 125 ft for both views. Humminbird’s manual and help center give different 2D sonar depth figures, so we leave that number out.
Side imaging changes how you search. On a bass boat idling down a riprap bank or a dock row, you can see brush and rock off to one side and mark them on GPS before you cast, instead of driving over every spot. Down imaging alone shows only what passes under the hull, which is enough on a small lake you already know but slower on a big reservoir. Our side imaging vs down imaging guide explains the trade in more detail.
Maps and Networking
Both listings name the same mapping package as the HELIX 5: GPS, a Humminbird Basemap covering 10,000+ lakes and continental U.S. coastlines, and AutoChart Live, which records depth contours, bottom hardness, and vegetation with eight hours of built-in recording. For more capacity, the listings point to AutoChart Zero Line SD cards, and they list compatibility with LakeMaster, CoastMaster, and Navionics charts. Compatible is not the same as included, so budget for a chart card if you want premium maps.
Networking is the main reason to choose a G4N. Both listings name Ethernet ports, Bluetooth, built-in NMEA 2000, and integration with Minn Kota and Cannon products. On a boat with a Minn Kota bow motor, that is the line to look for. Humminbird’s compatibility chart lists Minn Kota motors with i-Pilot Link (such as Terrova, Ulterra, and PowerDrive) and motors with built-in MEGA imaging for both HELIX 7 G4N models, with adapter cables in some cases, so check your exact motor on that chart.
Transducer, Mounting, and Power
The MEGA SI kit lists an XNT 9 HW MSI 150 T transom-mount transducer and a gimbal bracket, and no trolling motor mount. That suits a bass boat or an aluminum boat with room on the transom. A side imaging transducer reads off both sides, so where it sits on the transom matters; follow Humminbird’s installation instructions for the transducer, and see our guide on where to mount a transducer on a boat.
The control head needs a transducer you already own or buy separately. One option is Humminbird’s XNT 9 HW MDI 75 T, whose Amazon listing names compatibility with HELIX 7 and 8 G3, G3N, and G4N models with MEGA Down Imaging, a 20 ft cable, and a built-in temperature sensor. Match the transducer to your exact model number before you order. Both units list a power cable but no battery. Humminbird’s HELIX manual lists a 10 to 20 VDC power input, and its HELIX 5 and 7 installation guide calls for a 12 VDC supply and a 3 A fuse; follow that guide and leave anything beyond it to a marine electrician.
What Owners Say About the Control Head Only Version
Only the 411640-1CHO listing had owner reviews we could use, so these comments apply to that version, not to the MEGA SI kit.
- Trolling motor pairing. One owner says it matches up with a Minn Kota trolling motor. Another, in a short review, mentions “the lake vu master card if you want this to work with your trolling motor” and calls it “an ok unit for basic display.”
- Bow display with other transducers. One owner uses it with a MEGA Live transducer at the bow. Another bought it to run MEGA Live Imaging on this unit and MEGA 360 on another HELIX, and hooked it up to the One Boat network. A third calls it a great unit for the bow of a boat.
- A defect report. One owner received a defective unit and describes a delayed refund on the return.
How It Compares
- Humminbird HELIX 5 CHIRP GPS G3. Per its listing, it keeps the same basemap and AutoChart Live on a 5 in screen (per Humminbird), but names no imaging and no networking. Our Humminbird HELIX 5 review covers it.
- Garmin ECHOMAP UHD2 73sv. Garmin’s ECHOMAP UHD2 73sv page lists a 7.0 in touchscreen with keyed assist at 800 x 480 pixels, preloaded Navionics+ U.S. lakes charts, built-in ClearVü and SideVü with a GT54UHD-TM transducer, NMEA 2000, and Wi-Fi. It is the closest Garmin match to the MEGA SI kit; see our Garmin ECHOMAP UHD2 73sv review.
- Garmin Striker Vivid 7cv. Garmin’s Striker Vivid 7cv page lists a 7.0 in keyed display, ClearVü with the GT20-TM transducer, Quickdraw Contours as its map option, and Wi-Fi, with no side imaging. It fits anglers who want down imaging and their own contour maps without charts.
Who Should Look Elsewhere
- You have no transducer and want the control head. The 411640-1CHO ships without one; the MEGA SI kit is the complete package.
- You fish from a kayak or small jon boat. A 7 in head and a side imaging transom transducer take space; the 5 in HELIX 5 may fit better.
- You want a touchscreen. Neither HELIX 7 listing describes one; Garmin’s ECHOMAP UHD2 73sv lists a touchscreen with keyed assist.
- Your Minn Kota motor is not on Humminbird’s chart. Humminbird’s compatibility chart names the i-Pilot Link and built-in MEGA imaging motors that work with these G4N units; if yours is not listed, check with Humminbird or a dealer first.
Why You Should Trust Us
We do not conduct our own product trials. This review draws on the Amazon listings for both HELIX 7 units, the listing for the XNT 9 HW MDI 75 T transducer, owner reviews on the control head listing, Humminbird’s help center and HELIX manual, and Garmin’s own pages for the comparison; we name the source of each figure. The AnglerTechLab Score starts from Amazon owner ratings, with a limited editorial adjustment explained on our How We Review page; the MEGA SI kit’s score includes a 0.2 deduction because its listing gives 125 ft for MEGA Down Imaging, while Humminbird’s manual lists 75 ft with the included transducer; the control head has no adjustment. Commissions never change our verdicts.
Final Verdict
For most anglers shopping for a Humminbird HELIX 7 fish finder, the G4N MEGA SI kit is the better fit when you need a complete package: side and down imaging, a basemap, AutoChart Live, and networking, with the transducer in the box. The G4N MEGA DI control head makes sense only if you already have a compatible transducer or want a networked second screen. For other brands and sizes, see our fish finder reviews and our best fish finder picks.
Frequently Asked Questions
Does the Humminbird HELIX 7 come with a transducer?
It depends on the version. The HELIX 7 G4N MEGA SI kit (411940-1) lists an XNT 9 HW MSI 150 T transducer in the box. The HELIX 7 G4N MEGA DI (411640-1CHO) is a control head only, according to its listing.
Which Humminbird HELIX 7 transducer do I need for the control head?
For MEGA Down Imaging, the XNT 9 HW MDI 75 T transducer lists compatibility with HELIX 7 and 8 G3, G3N, and G4N models with MEGA Down Imaging (see the transducer section above). Confirm the match for your model number with Humminbird or a dealer.
How do you install the Humminbird HELIX 7 transducer?
Follow Humminbird’s installation instructions for the transducer; the 411940-1 kit lists a transom-mount transducer and mounting hardware. We do not give step-by-step directions here. If you are not comfortable drilling the transom or routing cable, have a marine dealer install it.
How do you read a Humminbird HELIX 7 fish finder?
Start with the 2D sonar view, where the bottom shows as a line and fish as arches. Then add the imaging views: down imaging shows structure under the boat, and side imaging shows it off each side, with the boat’s path down the middle. For a primer on 2D screens, see how to read a fish finder.
Is the Humminbird HELIX 7 a depth finder too?
Yes. Any sonar fish finder reads depth under the transducer. Humminbird lists MEGA Down Imaging to 125 ft with the MDI transducer and 75 ft with the MEGA SI kit’s transducer; its documents give different 2D depth figures, so if you fish deeper water, confirm the 2D depth rating of your transducer with Humminbird before you buy.
About the author
Mason McKinney enjoys fishing Minnesota's lakes for crappie, walleye, and other freshwater species. He uses forward-facing sonar, GPS fish finders, and spot-lock trolling motors to locate fish around underwater structures and maintain precise boat positioning.