DFF3D unable to work in deeper water

[brookes]

Aloha from Hawaii,

Wondering if anyone else is having problems with their DFF3D reading depths greater than 600'. I am a deep drop fisherman and fish ranges from 600-1000'. I was told that it would read as deep as 1200'. I was so ecstatic to purchase the DFF3D with my TZT2 12" MFD with very high hopes. I have used it three times thus far and it works in depths below 300' but when I head to my fishing grounds, it is unable to read the bottom. I have tried the sonar mode, side scan mode, 3d mode and none of them read the bottom at the depths that I fish. I have messed with every conceivable setting on the unit to no avail. Spoke to a Steve (very nice) at technical support who suggested that this might be a problem with grounding wires, but when I inspected the wires, there was nothing wrong with any of the wires. Read the manual inside and out. Ducer is placed in proper position.

This is what I see at the 600' range.

Frustrated and wondering if I wasted a significant amount of money on a product that so far, has not lived up to the hype, or if there is a fix for this. Any help would be greatly appreciated!

 

[brookes]

Wondering who else uses this unit for deep drop and how far down are you able to see?

 

[Johnny Electron]

Snips is out but he would be best to help you with this. Your missing something because we got a lot of these out there working great. I have seen one showing good bottom well below 1000 ft although I think they quote less in the documents.

 

[C-Bass]

Good afternoon Brookes,

Thank you for your inquiry. We also appreciate the photo that you supplied, based on what i could see it appears you either have a tremendous amount of turbulence going over the transducer face that could account for the gaps in the photo that you provided where the bottom is missing. If you are confident that the transducer is working in clean water then it appears the DFF3D is having a hard time locking on to the correct bottom signal and it could be cycling to deeper depths if you are running the sounder view in Auto Range. If the sounder is cycling between depths it is because it does not think it is getting a good bottom signal which could be due to noise in the system. I know you mentioned that the transducer has a solid ground and that the DFF3D box has a solid ground but I cannot tell based on the photo that you are experiencing noise in the system. The photo that you provided when it shows the bottom does appear to be heavily affected by noise or you have the sensitivity really cranked up.

I know we would appreciate another photo of the sonar view like the photo below.



As you can see in this photo that is a sector which is showing quite a bit of noise. If you can provide a photo of this view and range this view out to see below the bottom it would really try to help us what is going on.

I suspect the ground points that you are using could be noisy, or there is something else on the boat causing the sounder to lock on to not lock onto the bottom profile. Either way based on the photo that you are showing it appears that noise is the culprit?

Please see the photo below, the circle that i made in blue shows a nice bottom tail but it does not continue to carry on, it cleans up after a while. In the photo that you provided the space below the bottom where the bottom tail is continues on for quite a while and is really messy. My guess is if you where to range out even further in the photo and provided it would really never clean up, that is caused by noise.




You could try to play with the bottom level detection, the default is "0." I would try to move this down to a "-20" to see if the sounder can stay locked on the bottom. The other option would be to try an isolated power supply or even another spare battery to completely isolate the sounder when you get to deeper water. If you do this i would kill everything on the boat except the TZT2 and the DFF3D, engine off, inverter off, ect. and start to turn things on to see if you can see where the noise is coming from.

 

[brookes]

C-Bass and Johnny Electron,

Thank you so much for the information. I have a thu hull ducer with a high speed faring block, so I do not believe turbulence is the issue. It must be noise or interference. The DFF3D is mounting adjacent to the FAP-7011 and the ground wire is shared with this unit. Could this be causing noise? Might be a stupid question, but is there a way to test the ducer while out of water?

Again, appreciate all of the help.

 

[C-Bass]

When you say the ground wire is shared with the Furuno Pilot, what is the source of ground for these systems?

 

[brookes]

If you take a look at the bottom right of the picture (poor lighting), the ground wire from the DFF and the FAP-7011 are both grounded to what looks to be the mounting bracket for the FAP-7011

 

[C-Bass]

Thank you for your photo.

I see what you mean by the green wire. That is to earth ground, do you know where on the vessel the earth ground is located? Is it to a grounding plate that has contact with the water? Is it to the engine block ETC?



I also see that in the photo the transducer wire is not being clamped. Based see that it has some appears to have been clamped in the past, did you remove the transducer clamp only for the photo? Is the transducer clamp usually in place?

It would be good to try and get some photos why you are out next, try shutting everything down other than the TZT2 and the DFF3D. All other breakers off, engine off, inverter off ECT. To see if that alleviates the noise. If it does not try taking the earth ground off to see if you see an improvement?

What about power isolation? Is that possible?

What other components equipment do you have on the vessel?
Type of Engine?
Type of alternator?
Regrigerator
Air con
Type of invert make and model?

 

[brookes]

Thanks, C-Bass. Not sure where the earth ground is located but I can check when I get home.

I took off the transducer wire clamp to check the sheath....it was clamped properly prior.

Will certainly get some photos the next time I am out.

I can try to isolate the power by hooking up to dedicated battery.

Boat is a 22 admiral defiance with twin honda 100 outboards. unfortunately, no refrig or AC.

Big thanks for walking me through this!!!

 

[brookes]

Another question...talked to a friend who pointed out that the transducer for the DFF-3D transmits a frequency of 165Khz, which may not be suitable for imaging deep water. I have had in the past a 1KW transducer with 50/200 khz frequency and used the 50 khz setting when deep dropping. Seems like the 165 Khz would be good for shallower water esp depth under 600.

Can anyone explain how the 165khz is supposed to image deeper waters when, traditionally, we use low frequency to accomplish this? tnx

 

[C-Bass]

Good afternoon Brookes,

Thank you for your inquiry. Typically when trying to target fish deeper you look at (2) variables: Frequency and Output Power. Rule of thumb, the lower the frequency the deeper it will go. So yes, if trying to target fish deep it is much better to use lower frequencies. So for example, if you had a fishfinder with (2) transducer's that work at the same output power, say 1kw. And the frequency of those transducer's where 28khz or 200khz. The 28khz would go deeper.

Yes the because of the frequency of the DFF3D at 165khz it was not reallyt designed to be used for deep dropping for depths over 1000ft. Depending on the water conditions, water temp, salinity, picnocline, thermocline you may find it will work deeper than that.

Ideally the DFF3D will be used for pelagic fishing depths and to look at the bottom profile for stuff under 1000ft.

There is also a big difference of finding bottom deeper than 1000ft and trying to find a fish target deeper than 1000ft.

Regardless, with the photos you have posted as you know it is not working at its optimum level and we need to figure out the cause.

Kind Regards,

 

[brookes]

Thanks C-Bass. I actually took the boat out to try to fine tune the DFF3D. Turns out the ground wire was the culprit for the noise...once I removed the ground wire, it began working fine...still, not optimal for deep water, but I was at least able to mark the ocean bottom and see some fish....so, thanks for that advice.

Now, I need some advice on how to fine tune the unit. Is there a user's guide that goes in depth on how to fine tune the unit to get it to work better? I had it working at one point, then I tried to mess with it to fine tune, and I lost bottom again. Which settings should I be tweaking for deeper bottom....tvg? clutter, gain, etc.

Also curious which fish finder would be best for deep dropping. DFF-UHD with chirp???

thanks!

 

[brookes]

I'm asking about other fishfinders as I am seriously contemplating getting another unit

 

[C-Bass]

Brookes,

It would be helpful to see a couple of photos of the DFF3D now that you got noise cleaned up from there we will likely be able to give you a couple of ideas to improve deep water performance.

Also we need to know what other equipment is on the vessel to determine what kind of fish finder would fit with your style of fishing.

We also need to have some more details about your vessel, size, length ect.

 

[brookes]

Here are some pictures from my last trip.


View attachment 2View attachment 2Hi C-Bass.


I was able to mark as far down as 150 fathoms (900ft) and able to see some fish as well. When I am in the triple beam mode, it seems like the image on the right has the strongest signal and the middle and left are rather weak. Also, looking at the 3d mode, I am able to capture more grounds on the port side of the boat, but the SB side doesn't pick up to much ground laterally.

As for equipment, I have a Defiance Admiral 22' EX with twin Honda 100 outboards on an engine bracket. My system is a complete Furuno package with a TZT2 12 ", DFF-3d, Autopilot 711c and a DRS4D-NXT radar. Let me know if you need any more information. Tnx!

 

[brookes]

 

[C-Bass]

Good morning Brookes,

As you can imagine it can be hard to recommend settings without actually being on your vessel on any particular day. As ocean conditions change, sea state changes, turbulence, and other dynamic layers such as plankton, thermocline, pycnocline, ETC. changes to your sounder settings will need to be adjusted.

To start with you could try experimenting with some of these settings.

1.) TVG: Make sure the TVG distance is set to a depth that you are actually fishing in. The default value is 1000m. Which means if you have not changed the TVG value and you are fishing in 1000ft of water you will not be getting the full sensativity of sounder. So I would set this value to say 1000ft if that is the depth you are fishing in. There is also another TVG value, the default value is 5. I cannot remember if this sounder follows the "less is more" saying. Meaning, the lower the TVG value, the more stuff you will see on the screen. So once you have the TVG distance set, if you are still not seeing enough on the screen try lowering or raising the other TVG value (not distance) to increase the sensitivity. You should see more information on the screen depending on what way you move this variable.

2.) When looking for fish deep on the triple beam sounder, as you get deeper the outer beams will lose sensitivity. So we believe it is a good idea to narrow up the beams to 20 degree angles and set the beam width to 20 degrees as well.

3.) If you have not adjusted the speed of sound setting found in the Multi-beam sonar menu this may need to be adjusted. Make sure the system is set for salt water, the speed of sound is an important factor for multibeam systems. If the speed of sound is not set properly it will make the bottom look either convex or concave depending on the value if it is higher or lower. You could try using the automatic sound speed adjustment, info on that can be found in the DFF3D manual. Or you could manually adjust it by setting the speed of sound adjustment on a known flat piece of bottom, then use the cross section view to make sure the bottom line is flat, not convex or concave.

4.) For the 3D history display if you are trying to target fish right off the bottom you could try adjusting the Seabed Echo Calibration. The higher this value will allow the fish to differentiate themselves from the bottom.

 

[Scotty B]

Hello Brookes
Just reading your thread and see the bit about removing the Ground Wire.
So have you left it disconnected?
Reading the manual they stress that the ground must be connected.

 

[Bayhouse]

SWAG here - What transducer are you using and what do you have configured in settings?

I had gotten direction to set my 165/50/200Khz xducer to one that was a chirp xducer but couldn't get the xducer to work reliability. Changed the setting to a non-chirp xducer and it's been working great since.