I have a one year old 12" Helix with Mega Down imaging and Mega 360. It's a wonderful system except the interference can be quite bad when the Ultrex runs. So recently I've been crappie fishing brush piles I put out. It produces a wonderful image of these cinder block and bamboo brush piles. But on spot lock or Ultrex running the image can disappear in the inference. I've gone to using Chirp which is a lower frequency and not affected. Any suggestions?

Your power to your electronics should be completely separate from your trolling motor circuit and the wires should be apart from each other. I would not run the electronics off of a trolling battery either....

What he said. If your graph set up is not wired back to the battery on a dedicated system you could have interference issues.

Describe your power connections for the display and MEGA 360.

Also do you have an on-board battery charger that does the trolling motor batteries and the starting battery?
If so do you disconnect the trolling motor from the battery when charging the trolling motor batteries?

I have a Skeeter ZX 250. And I have the factory set bundle of wires to the bow. One set at 12 volts was unused. I put in a circuit bar and hooked THAT SET of red and black wires to the Helix unit through the circuit bar. The wires were not used for anything else. But I will check to make sure the Mega 360 is not somehow tied in with the wires for the old Lowrance Gen 3. The images on the Helix and Mega 360 are spectacular when I have no interference. So let me just make sure I made it simple. Red and black unused wires power the Helix. I can't remember whether the Mega 360 is powered with the Lowrance (think it goes to the same circuit bar as the Helix). Given the Ultrex is 36 volts, I'd never hook up a 12 volt device to a 36 volt system.

The unit is on the bow. And everything powered in the bow has wiring right there in a five inch square area.
The recommendation I got to go back to the non trolling motor battery is essentially how the boat is wired now.
Thanks

Yes. Four bank battery charger.

Turn 36 V circuit breaker to off position when I charge batteries.

As a test, disconnect the battery charger leads to the starting battery to determine if the charger is the path for RFI.

Also your statement about using CHIRP makes no sense. The unit CHIRPs the MEGA frequency or the 455 frequency.

Look man I worked as a geologist for 35 years I know that subject better. I have two transducers, The transducer at the bottom of the trolling motor and the round spinny thing on the stick hooked to the trolling motor. The spinny one requires its own power and is obviously being interfered with. The transducer at the bottom of the trolling motor is powered by the unit. Regardless if I am calling the wrong terms, the standard sonar is not disrupted by the trolling motor. If for some reason that battery charger is the source of the interference by simply being hooked up to the power battery what are my alternatives?

I'm assuming you are suggesting I take the leads off starting battery and then run the unit. Too bad I simply don't have an on/off switch in that circuit because if you are familiar with a ZX 250, I have to unscrew and remove a plate covering the area where the battery stores. It is a PITA.

No the battery charger would not be the SOURCE for RFI, just the PATH. You disconnect the PATH to verify the trolling motor is the source.


Bottom line is your trouble shooting is only as good as the effort you put into it.

You need to run a ground wire from the tm head, to your negative battery side.

I just ground a bare spot on my tm head and ran the wire down and hose clamped it the other end goes up the shaft to the negative wire for tm power on my bow.

Ive shared this with a few people on the water and it has gotten rid of m360 and side interference when the tm is running.

Open your Ultrex head unit, there is a 3 amp fuse there, if that fuse is blown then your lower unit has no ground, and that's why you have interference. 95%+ chance this is your problem, simple solution.

Start watching this at the 1:52 mark, I show you where it is exactly