Panoptix PS-21 & PS-30 report

[DonnieG]

That could be a few things.

The trolling motor wont draw much power at all when its out of the water - no resistance to the turning blades. At lower power levels, there will always be less electronic interference generated.

Also, the grounding paths are different when the motor is in the water. You could have some ground loop type things going on. This is vaguely related to bonding the battery grounds and/or disconnecting the charger leads as possible fixes. Depending on how and where the noise is being generated, sometimes it helps to connect things up and sometimes it helps to disconnect things.

I lean towards the less power = less noise as the main thing here though.

This one might be hard to find..I took my transducer stick over to the running TM and laid the PS-21 on the TM...No interference..

[Larry3215]

This one might be hard to find..I took my transducer stick over to the running TM and laid the PS-21 on the TM...No interference..

I dont think this is the kind of interference that can be transmitted that way. When you're in the water, there are two types of signal interference.

One is sonic. The trolling motor is generating sounds that happen to mix the wrong way with the sonar signals the transducer is generating.

Two is electronic noise - which could be generated in several different ways and come from different sources inside the TM - see lwinchesters post.

Its almost certainly #2 and the noise is probably passing through the wiring/grounding one way or another.