Topic: static problem with 798 after interlink install

[LocDown]

is there a setting I can change to get my sonar readings clean again?

Before:

marion 20110416

After:

humminbird static

[FuzzyGrub]

Did you have noise on both units? 

Do you get the noise if other unit is off?   (is it interference?)

Do you get the noise as soon as you hook-up interlink? 

Post how your system is configured.


Is everything powered from same battery?  If different batteries, are they grounded together?

[LocDown]

1. I just have noise on the 798
2. I have tried with the 778c on and off. It makes no difference.
3. Do you mean noise as if the boat is out of water and just powered on? I get a clean reading with the boat on the trailer(had the transducer in a bucket of water also to test). The 798 had clean sonar readings the day before on a different boat. It was just the unit and trolling motor transducer(different one).

798 is connected to  weathersense to choke to interlink head 1
778c is connected to 10ft+20ft cable to choke to interlink head 2

Both units are powered via starting battery.  798 is connected to a fuse box then to the battery. The 778c is connected directly to battery.
The 798 is on the console and the 778 is at the bow.

This is a center console type boat so before there was only the power/ground for the 778 running up front with the trolling motor tranducer. Now it also has the interlink cables running through the same routing tube and I have moved the trolling motor transducer to the rear as a shoot thru at the moment also in the same tube.

I will try other stuff next time out.. .might be a couple of weeks tho.

[FuzzyGrub]

Isolating noise is a process of elimination.  You try to figure out what is generating the noise, and how it is getting into the electronics.   Start when you are on the water and experiencing the problem.  Shut the motor off, trolling motor, and then any other possible devices to figure out what is generating it.   Finding that will give clues to what wire routing etc, that might be changed.

Other things to try:
- Your units should be swapable.  Put the 798 on the bow and see if the noise follows. 

- Swap interlink connections and see if the noise moves.

- Remove weather sense from the equation, etc.

[LocDown]

Ok, I was out today and had removed the interlink cable to the front unit and then tried with both finders on. No go. I shut the front finder off and the 798 screen cleaned up. So, now I will move the shoot through back to the trolling motor and try again with the interlink cable.

[FuzzyGrub]

It sounds like you are getting sonar interferance.  How far apart are the two transducers and how deep of water were you in? 

[LocDown]

the transducers were about 3ft apart. shoot-through and transom mounted. ...I am changing the shoot-through and putting on a trolling motor one.

[Humminbird_Greg]

If it only happens when both units are on; try turning on and up the Noise Filter menu in the unit showing the interference.

[LocDown]

I have tried the noise filter and still no go.

[LocDown]

will try again with shoot through disconnected and coiled up and interlink reconnected with trolling motor transducer connected. ...after I get the boat out of the shop.  The unit shows very good returns on my pond boat. .only thing is, my DI is never super clear. I have tried with chart speed 1 and 2, not as clean as I would like.