Humminbird Helix G3 troubleshooting

So got out on the water the last couple days to play around with a new Helix 7 G3 unit and have some questions for you guys with more experience.

1. What is the trick to getting these units to read bottom at higher speeds? This is transom mounted on an aluminum boat and once you hit about 12-15 mph it loses bottom and shows 1,000+ feet (2D, SI, DI doesnt matter). Transducer was mounted per manual with the seam about even with bottom of transom (maybe a touch below it). It was leveled side to side and top to bottom with the boat at normal search speed of 3-5 mph. This is the high wide mega transducer.

There is also an older transducer (xnt 9 20T) from a prior unit on the opposite side of the transom. When that transducer is connected to the helix 7, it still loses bottom. However, if i connect that old transducer to the old unit that originally used that transducer, that unit can hold the bottom reading at top speed. So it seems to be something with the head unit as opposed to transducer placement or something like that.

2. What sensitivity numbers are typical for the SI view? Everything i read says the default of 10 is pretty close and a range of 8-12 is pretty much good to cover most all situations, however i seem to be using quite a bit lower at times. First lake was murkier and on the mega frequency i was around that 8-12 range but when switching to 455 would have to back it down even lower. On the second lake with cleaner water, i had the 455 set to negative sensitivity values to keep from making the image white hot and the mega to 3 or 4. This was especially apparent in shallow water / hard bottom, which brings me to my next question…

3. I am curious how you can tell which variable is making your return stronger between shallower water and harder bottom. Every time we would drive over a reef of shallower water the bottom woukd show a much brighter return. I am not sure if it is more due to the shallow water or the harder bottom. It would be super beneficial to show transition lines of bottom composition but I am not sure how much to believe whether it truly is a bottom change or just shallower water? I did see some scattered rubble in places but definitely not everywhere.

#1 is the older ducer lower in the water in relation to the hull than the new one?

I mounted my SI ducer almost flush with the bottom of my hull. I don’t get high speed readings because it’s not far enough in the water while on plane. This was intentional so that it can’t get knocked off from hitting something.

Do you have a little downward tilt at the rear of the transducer as it is needed when running at speed.

Where you mounted your transducer is there anything on the hull that can produce turbulent water strakes rivets a step etc.

pfunk wrote:

What sensitivity numbers are typical for the SI view? Everything i read says the default of 10 is pretty close and a range of 8-12 is pretty much good to cover most all situations, however i seem to be using quite a bit lower at times. First lake was murkier and on the mega frequency i was around that 8-12 range but when switching to 455 would have to back it down even lower. On the second lake with cleaner water, i had the 455 set to negative sensitivity values to keep from making the image white hot and the mega to 3 or 4. This was especially apparent in shallow water / hard bottom, which brings me to my next question…

Range should be a higher value: Like 20-200′ I run mine at 80′ most of the time when searching for fish and sometimes higher when looking for bottom structure like a rock pile. I almost always have my contrast set at 14. I adjust the sensitivity depending on how fast i’m going and how deep it is. Mega SI doesn’t work speeds higher than about 10MPH. I get my best readings at 2-5 MPH.

pfunk wrote:

It would be super beneficial to show transition lines of bottom composition but I am not sure how much to believe whether it truly is a bottom change or just shallower water? I did see some scattered rubble in places but definitely not everywhere

Typically if it’s a shallow water reef or structure it’s going to be hard bottom. Off the edges of these structures you will find the transition line. It’s quite easy to spot and is typically not a huge depth change. It’s usually only a foot or two difference where the bottom changes from hard to mud / soft.

With all that being said, you do need to change the sensitivity in correlation with the depth and speed at which you are traveling at.

As far as your old transducer not reading on your new unit at high speeds but working just fine on your old unit, that’s kind of a head scratcher. Are you sure that it’s actually pulling signal from that transducer? Did you unhook the mega imaging transducer and only hook up the 2d transducer to be sure?

patk wrote:

#1 is the older ducer lower in the water in relation to the hull than the new one?

I mounted my SI ducer almost flush with the bottom of my hull. I don’t get high speed readings because it’s not far enough in the water while on plane. This was intentional so that it can’t get knocked off from hitting something.

The older transducer is a touch lower in the water than the SI one. SI is mounted with the center seam on the transducer even with the bottom of the hull. But regardless, the new Helix unit doesn’t keep a bottom signal on either the MEGA transducer OR the old one which is mounted lower. An older Humminbird unit has no problems keeping the bottom signal when hooked up to the old transducer. So the problem must be in the head unit and after digging some more it looks like the latest software update addresses some 2D sonar issues so we are going to give the update a try.

Tom P. wrote:

Do you have a little downward tilt at the rear of the transducer as it is needed when running at speed.

Where you mounted your transducer is there anything on the hull that can produce turbulent water strakes rivets a step etc.

Actually there is a slight upward tilt at the rear of the transducer. This is because the bow of the boat sits higher than the stern and we compensated for this to make sure the transducer would be level to the lake bottom.

We made sure to level the transducer after first jacking the tongue of the trailer up to get the boat to sit like it does on the water. This was done by finding the level point on the water and then recreating it at home on the trailer. The transducer was then mounted level to the ground which is what results in the slight upward tilt at the rear of the transducer when you lower it back down at the tongue. Hope this makes sense.

Pat McSharry wrote:

<div class=”d4p-bbt-quote-title”>pfunk wrote:</div>
What sensitivity numbers are typical for the SI view? Everything i read says the default of 10 is pretty close and a range of 8-12 is pretty much good to cover most all situations, however i seem to be using quite a bit lower at times. First lake was murkier and on the mega frequency i was around that 8-12 range but when switching to 455 would have to back it down even lower. On the second lake with cleaner water, i had the 455 set to negative sensitivity values to keep from making the image white hot and the mega to 3 or 4. This was especially apparent in shallow water / hard bottom, which brings me to my next question…

Range should be a higher value: Like 20-200′ I run mine at 80′ most of the time when searching for fish and sometimes higher when looking for bottom structure like a rock pile. I almost always have my contrast set at 14. I adjust the sensitivity depending on how fast i’m going and how deep it is. Mega SI doesn’t work speeds higher than about 10MPH. I get my best readings at 2-5 MPH.

<div class=”d4p-bbt-quote-title”>pfunk wrote:</div>
It would be super beneficial to show transition lines of bottom composition but I am not sure how much to believe whether it truly is a bottom change or just shallower water? I did see some scattered rubble in places but definitely not everywhere

Typically if it’s a shallow water reef or structure it’s going to be hard bottom. Off the edges of these structures you will find the transition line. It’s quite easy to spot and is typically not a huge depth change. It’s usually only a foot or two difference where the bottom changes from hard to mud / soft.

With all that being said, you do need to change the sensitivity in correlation with the depth and speed at which you are traveling at.

As far as your old transducer not reading on your new unit at high speeds but working just fine on your old unit, that’s kind of a head scratcher. Are you sure that it’s actually pulling signal from that transducer? Did you unhook the mega imaging transducer and only hook up the 2d transducer to be sure?

This is helpful. I am indeed talking about shallow water structure. Like you said the transition line was very abrupt and very easy to see. I wanted to know for sure what i was seeing was due to a bottom composition change and not just the unit’s sensitivity being set too high as the depth became shallower. I can see this being incredibly helpful for locating bottom composition changes. It’s so obvious on SI.

As far as the transducer, it is definitely getting signal. The entire head unit was moved and transducer cable of the MEGA transducer was unplugged. On the old transducer it would read depth just fine, but again at speed it would lose signal just like on the SI transducer. I do believe this is a software issue now though after seeing 2d sonar issues listed as a fix in the latest software update.

I have another question for everyone running MEGA SI. I am only getting about 55-60 feet or so of range on the mega setting before the bottom starts to darken quickly. I know the water and other factors may prevent you from getting the full 125 foot range on each side, but does it sound normal that i was only able to get less than 1/2 the advertised range in relatively clear, shallow water? Or when Humminbird says 125 feet on “either side” of your boat, does that mean the TOTAL range is 125 feet so if you’re running it on both sides, you’ll only get about 60 feet per side?

Maybe the older 2d ducer has a compatibility or performance issues with the newer chirp unit?

I’ve always erred with having my SI ducer tail slightly tilted down and have always had solid imaging and can run at 40mph without losing bottom.

Tipped up at the tail will give you the least probability of catching enough of a return signal to hold a display.

______________ wrote:

Maybe the older 2d ducer has a compatibility or performance issues with the newer chirp unit?

I’ve always erred with having my SI ducer tail slightly tilted down and have always had solid imaging and can run at 40mph without losing bottom.

Tipped up at the tail will give you the least probability of catching enough of a return signal to hold a display.

The old transducer is compatible with the new helix unit. I did confirm that. I think the problem is the current software on the Helix needs to be updated and hopefully that fixes it.

I can try tipping the transducer down if the software update doesnt fix the issues. I guess I figured that you would want the transducer to be level with the lake bottom for the best return but i suppose having it tipped slightly downward would shoot the signal forward some. Not sure if it is possible to “outrun” the return signal and shooting it forward a bit helps prevent that.

In reality it probably is tilted forward a little bit when the boat is at full speed since the bow sits even higher at full throttle than it does when idling around at 3-5 mph (transducer was leveled at a speed of 3-5 mph).

The “tilt” of the transducer is all relative to boat positioning so I guess what one guy calls tilted forward might not be the same for another guy unless their boats are sitting on the trailer at the same angle.

I have been having the same problem with my Helix 10.Have you found a fix for the the problem yet with yours?

Fishing59 wrote:

I have been having the same problem with my Helix 10.Have you found a fix for the the problem yet with yours?

Not yet Dave. Had some things come up and haven’t been able to try a software update yet but that is the next step. Which software version are you using?