Thread: Getting bad interferance on HB

Originally Posted by Cane Pole

You fellers with all the noise, do you have metal or plastic boats? This makes a difference.

Metal boat here Tom.
Mine works good until I turn the Terrova on. And if the trolling motor is on high its not as bad?
May try what Jeff has done. And trick it with telling it I'm using a different transducer.

Pete

All metal boats have grounding loop problems. If you remove the ground loop, this usually fixes the problem.

If you isolate your TM bracket from your boat chassis (such as Motorguide rubber isolator shock mounts), this removes the ground loop from the chassis by isolating the boat chassis from the tm. The Ground return to the battery then becomes the cable and not the cable and the boat chassis.

Simple to check with a ohm meter. If the ground lead to your TM reads continuity (short) to the chassis, the you have a ground loop. This means that current returns from the TM to the battery thru the cable and also to the battery thru the boat chassis (via engine) to the battery negative. This constitutes two return paths (ground loop) to the battery negative thus causing the ground loop. Plastic boats don't have this problem unless someone hacked the ground wire.

Ask any good radio man about this ground loop phenomenon.

Originally Posted by Cane Pole

All metal boats have grounding loop problems. If you remove the ground loop, this usually fixes the problem.

If you isolate your TM bracket from your boat chassis (such as Motorguide rubber isolator shock mounts), this removes the ground loop from the chassis by isolating the boat chassis from the tm. The Ground return to the battery then becomes the cable and not the cable and the boat chassis.

Simple to check with a ohm meter. If the ground lead to your TM reads continuity (short) to the chassis, the you have a ground loop. This means that current returns from the TM to the battery thru the cable and also to the battery thru the boat chassis (via engine) to the battery negative. This constitutes two return paths (ground loop) to the battery negative thus causing the ground loop. Plastic boats don't have this problem unless someone hacked the ground wire.

Ask any good radio man about this ground loop phenomenon.

Thanks Tom..
I may have to get you to check it when were at Paris. :D
I was with you until you got to the part about ground loop. LOL
MY trolling motor is mounted on the rubber mounts. But not the solid mounts your talking about. I may run a piece of rubber pipe up the bolts and see if that take care of the problem..
Also getting white spots showing up on the SI unit like Todd had with the new boat. The old War-Eagle did not have these. So you may have my problem nailed down.
Trade you some 1/2 oz jig for a test.:D Tied up in the color you say.
Pete

I use to have the same problem with an old Eagle finder and they suggested to run a ground from the negative side of the battery and attach it to the metal boat. It worked great.

Originally Posted by ifish

I use to have the same problem with an old Eagle finder and they suggested to run a ground from the negative side of the battery and attach it to the metal boat. It worked great.

This can also create other problems as it introduces yet another ground loop. Sometimes it works, sometimes it doesn't.

Originally Posted by ShilohRed

Thanks Tom..
I may have to get you to check it when were at Paris. :D
I was with you until you got to the part about ground loop. LOL
MY trolling motor is mounted on the rubber mounts. But not the solid mounts your talking about. I may run a piece of rubber pipe up the bolts and see if that take care of the problem..
Also getting white spots showing up on the SI unit like Todd had with the new boat. The old War-Eagle did not have these. So you may have my problem nailed down.
Trade you some 1/2 oz jig for a test.:D Tied up in the color you say.
Pete

I will bring my meter Pete.