Graph clutter when engaging trolling motor

[bassin_louisiana]

See photo. When I engage my trolling motor, I get the lightwr blue vertical screen clutter you see. When I let off, it goes away. I am wondering if this is caused by my HDI skimmer transducer moving inside the weed guard when I am moving. But what makes think this is not the cause is that vertical light clutter continues as long as my foot is on the trolling motor. Any suggestion?

 

[Scott Danforth]

cavitation bubbles from the trolling motor prop

 

[dingbat]

It’s not motion related.

Trolling motor transducer mount?

What frequency (pulse) is your trolling motor running at?

What does the noise look like on conventional sonar?

 

[bassin_louisiana]

HDI Smimmer Hose clamped twice with metal weed guard. Running high chirp are 455 kHz. Sonar also has a break like this when engage the pedal.

 

[dingbat]

HDI Smimmer Hose clamped twice with metal weed guard. Running high chirp are 455 kHz. Sonar also has a break like this when engage the pedal.

Ok, Lets back up. What unit? What transducer are you running? Have a link to this weed guard?

What is the full CHIRP band? 455kHz in of itself isn't CHIRP. CHIRP is a band (spectrum) of frequencies broadcast simultaneously. High CHIRP is typically 150-240 kHz

 

[bassin_louisiana]

Lowrance Hook 9 w/ HDI Skimmer ducer. High chirp. 800khz. 2018 Maxxum 70lb/24V.

 

[tblshur]

is the lowrance and trolling using same battery ? are the power wires run up the same side of boat?

 

[bassin_louisiana]

They are both on same battery and both run up same side.

 

[tblshur]

BL i would run a test wire from the back of boat to unit also use a different battery if that helps then you can permantly in stall wire or battery hope this helps :joyous:

 

[gm280]

Obviously interference. The problem is where is it coming from. I know it is the trolling motor, but is it air frequency delivered or power line delivered. Power line could be the easiest to solve. If it is air transmitted, that gets a lot hard to eliminate. Do use a separate battery first and see what happens. If that clears it up, there's you answer. If not, it will take a lot more shielding or reinstalling pickups to different locations to eliminate the issue. Also try the TM out of the water (in the mount position) and see if you still get the problem. JMHO

 

[bassin_louisiana]

I have no idea what fixed it, but I just upgraded trolling motors, re-ran the cables, and there is no screen clutter at all. Weird. Maybe I moved wires around and fixed interference.