Thread: Terrova all hooked up....but Interference in my fish finder

How do you solve PWN noise issues and what exactly is that? My terrova causes interference on my 1198 also.. but does not cause it at full speed so I guess I have PWN noise issues.

DoubleG

Originally Posted by Hunterjt

I placed the ferrite core on the lines with no help. I still have the problem as before, Im waiting on cable from HB now I really hope this help my problem. I even took the battery meter wire off to see if that was it then I unhook the us2 to see if thats it and I'm still trying. Has anyone used the cable from HB? I even took the finder and hooked it to a battery off the boat still no fix. He is a pic of what I'm getting. Thanks for all your help.

Attachment 75659

Hunterjt,
I did not know that you had the US2 on your Terrova. We have seen where two things with the US2 can cause trolling motor interference – and this is whether you are using the US2 or not:
1.) Check the fuse in the head of the trolling motor with an ohm meter (multimeter) to make sure that it is not blown. Don’t just look at it – test it to be sure.
2.) Make sure that all of the little round metal connectors for the US2 cable are tight. If they are loose they can also cause trolling motor interference – again: even if you are not using the US2. If you are using the US2 than be sure and check the metal connector that is on the Minn Kota to Humminbird adapter cable to make sure that it is tight as well.

There are some instructions and pictures here on the Humminbird web site about this:
Humminbird: America

Originally Posted by DoubleGobble00

How do you solve PWN noise issues and what exactly is that? My terrova causes interference on my 1198 also.. but does not cause it at full speed so I guess I have PWN noise issues.

DoubleG

In most cases, you can only mask the problem. Pulse width modulation is basically pulsing the motor at different durations of dc. The duration of the dc pulse determines an average dc level, which in turn determines the speed. On low speeds, the motor is pulsed slower which ends up with an lower average dc level and makes the motor turn slower. Kinda like a light dimmer effect (but not a light dimmer).

Originally Posted by DoubleGobble00

How do you solve PWN noise issues and what exactly is that? My terrova causes interference on my 1198 also.. but does not cause it at full speed so I guess I have PWN noise issues.

DoubleG

DoubleG,
PWM = Pulse Width Modulation. Basically instead of turning up or down the voltage to your trolling motor for those speeds between stopped and wide open; they pulse the 12 volts (or 24, 36,…) to the trolling motor at various speeds. If you select a slow speed this puling is slower and at a higher speed setting the pulsing is faster. This pulsing of energy causes a radio frequency and when the frequency of the pulsing matches that of the sonar; you get interference. At the highest speed the PWM circuitry is not operating so there is no interference.

You should contact the Humminbird Customer Resource folks and see if you need the trolling motor choke or any of the choke cables that we have.

Originally Posted by HARLEYBOY

Check The fuse in the Terrova Head, If it is blown there will be Interference, was in mine ,

No fuse blown in the head.thanks

Check those connectors...

Originally Posted by Humminbird_Greg

DoubleG,
PWM = Pulse Width Modulation. Basically instead of turning up or down the voltage to your trolling motor for those speeds between stopped and wide open; they pulse the 12 volts (or 24, 36,…) to the trolling motor at various speeds. If you select a slow speed this puling is slower and at a higher speed setting the pulsing is faster. This pulsing of energy causes a radio frequency and when the frequency of the pulsing matches that of the sonar; you get interference. At the highest speed the PWM circuitry is not operating so there is no interference.

You should contact the Humminbird Customer Resource folks and see if you need the trolling motor choke or any of the choke cables that we have.

Glad to see we are on the same page. You not one of my former students incognito are you? ha

Not unless you taught electronics in Birmingham Alabama CP.