I’ve recently install a Carbon on the bow, ghost trolling motor with upgraded SI transducer and Live at the console paired with the active 3-1 transducer. All units are connect via NEMA 2000. I’m seeing dotted lines across the side scan screen as shown in the pictures. I’m also getting a small square, what I though was a fish dot a first, out around 45-50’ mark on both the left and right sides. These squares are identical and located equally apart when they appear. I didn’t get a picture of the squares, only the dotted lines. I switch the carbon sonar setting to look at the live active transducer and still got the same results with the dotted lines. I didn’t think to let it run long enough to see if the squares popped up. Has anyone experienced this before? Could it be a noise filter issue?

FYI- Lowrance couldn’t fix my previous unit so they sent me the carbon, with a fee of course. I believe that they use refurb units for their upgrades but I’m not 100% sure if that. Any suggestions are welcome and appreciated. Thanks

The Live 12 unit will work with the SI transducer on the Ghost at the bow. Why not put the Live 12 at the bow and see how the image looks in that configuration? You'll rule out the Carbon that way.

That didn’t cross my mind while on the water. I’m going to check and re-secure all extra cabling individually with the proper loop diameter and switch the graphs on for the next trip. Thanks.

The consistency of those dots is either electrical interference or the transducer is seeing something related to the boat. I can't tell from the pics if its only on the right side or both. If its only on one side I would lean to the the transducer seeing something on the boat. Can you post a pic of the Transducer on your boat? Do you have the latest software update on your carbon? I will be in BP Garland on Sat this weekend if you want to bring it in I can look at it.

Interference is possible. I had that same thing happen on mine. When I upgraded to Active Imaging 3n1 the issue went away. So I attributed it to a transducer that was starting to fail.

He has the upgrade SI transducer on the Ghost (according to OP), and he has an Active 3-in-1 at the transom. He didn't say how/where the transom 3-in-1 was mounted, NOR did he say if the dot anomaly is from looking with the SI on the Ghost, or the SI from the transom, or both.

I have the Live at the console paired with 3-1 on the transom. The carbon on the bow is paired with the Ghost SI transducer. NEMA 2000 network between both setups. The dotted lines appear on the Carbon when looking at either transducer. I did not check to see if the Live, while looking at the ghost transducer, would show the dotted lines. There shouldn’t be anything visible that the ghost transducer could see in regards to the boat. The line are more apparent on the right side of the side scan. It was cold, windy and the fish were biting well. I fault myself for not taking more pictures. Could looping the extra cable slack in 6” diameters cause the issue? I will revisit the wiring tomorrow but I’m sure I didn’t give the loops 18”, don’t even have room for that.

I performed the upgrades on all units in December. I didn’t notice the dots the on the first trip out and I can’t imagine that I would have missed them.

I'm not sure which cable you are referring to as having loops in the extra length. That's generally more critical for transducer cables because the signal is analog and extremely low voltage. Ethernet cables (usually gray for Lowrance, have the gold connectors) are differential twisted pair digital signaling. By that physical layer design of Ethernet, it's usually very difficult for an Ethernet cable to get "crosstalk interference" from itself or another Ethernet cable when they are close together. Even so, it's better NOT to coil up such cables with loops of any consistent size as this puts many small sections of the cable in close parallel proximity to one another. It is BETTER to use random loop sizes that are not secured together - so that the cable isn't parallel to itself any more than necessary. The best arrangement is actually cabling that is randomly spread out using various routing in the space available. If the extra length of cable looks like a random spread out mess inside the bow area, that's probably far better than cables tied with neat consistent loops. NMEA2000 only moves low-speed data, no sonar data of any type, so don't waste any time moving NMEA cables around.

If the dots are only on one side of the side-scan display, I seriously doubt that the source of the interference is coming from any cable's positioning or a failing cable. This is because both left and right side sonar data move through the Ethernet cable on the same transmit wire pair. If there's physical cable interference for the right side data, it would also affect the left side data. The same goes for power supply noise that could cause an issue. If it happens for right-side views, it should also happen for left-side views. (Interference on a power supply wouldn't stop or start based on what display view you selected.)

At the Carbon unit on the bow, if you select the TM transducer, you're looking at data direct from the transducer - no Ethernet transmission of data is involved. If the Carbon unit is looking at the transom side-scan data, it gets such data via Ethernet from the Live unit at the console. These are completely separate physical routes. If you say the Carbon is getting dots for side scan no matter which transducer you select, then I wonder if you are actually getting data from only one place, but THINK you've selected a different transducer. To test this, while the Carbon is looking at the transom side-scan, unplug the 3-in-1 cable on the Live unit. If the Carbon's side scan disappears, then you had it selected correctly.