dff1-uhd Help

[fishray]

Hello, I need help with identifying the following screen info.
I was just finishing offshore for tuna, I took some pictures of the screen, the boat was not moving. Can someone please help explain what the screen reading is, I don't know what is fish. What are all the green/blue marks? Thank you.

 

[Deep Blue]

fishray,

What you are seeing is both "Baitfish" and the Individual "Fish Targets" that are hanging around the baitfish:



And the individual fish targets:



I did notice that the vertical evenly spaced lines next to the range bar could potentially be electronic noise. One way to combat this noise is to ensure that the MFD, DFF1-UHD, and the Transducer Shielding Wiring are all properly grounded.

- Deep Blue

 

[Quitsa]

That's pretty consistent with what I would see and I agree that you are probably seeing a bait ball and larger predator fish. But I would check the gain setting. If you were using "auto",you may need to go into the settings and apply "auto gain offset" if it is too high. The easiest check is to turn off "auto range" and then manually set the range to about three or four times the actual depth. You will see a strong bottom return at the actual water depth and a secondary return at twice the actual depth. If the secondary return is very strong and distinct and looks almost like the primary return, the gain is probably too high.

The vertical lines look a bit like the interference from a regular high frequency CHIRP caused by the overlap in frequencies with the DFF-3D, though they are more distinct that what I get perhaps because of a high gain setting. Try setting the interference filter to "high" and they should go away.

 

[fishray]

I was fishing in depths of over thousand feet. I had set my range 0-180 feet. And my gain was manual, not auto at 66.

 

[Quitsa]

I was fishing in depths of over thousand feet. I had set my range 0-180 feet. And my gain was manual, not auto at 66.

The returns from the baitfish are stronger than I usually see unless you were over an especially dense school. That suggests perhaps you have a bit too much gain.

Different species have different qualities of returns depending especially on the air bladder and other internal structures that reflect the sonar signal. Tuna have pretty good returns normally.

The vertical lines are not something you should see, however, and suggests something is going on.