I get interference on my sonar when I transmit on my radio. When I receive it is no problem. My radio and sonar are wired directly to the panel behind the dashboard. Some folks have told me to wire the sonar direct to the battery rather than the panel. What are you thoughts here?

I think that would help. That type of interference is from the sonar data cable acting like an antenna which is why you only get interference when you transmit. Also, one of those ferrite or torroid interference blockers mentioned by Grey Ghost in the previous thread (probably put it on the sonar / ducer data cable coming in to your unit) could help.

i don't know for sure on this one but if it was me i would try running a single power wire from the battery positive to the unit and leave the ground on the panel. put an inline fuse on the power wire and see if that stops it.

you definately don't want them on the same panel.

also put on some suppression ferrites can't hurt to snap them on.

I will try your ideas. The Suppression Ferrites came with the sonar and are on. Still have the problem. Time to rewire, which is an absolute pain in the butt. When they made the boat all they gave me was a 1 inch PVC chase and that sucker is full.

First, where is your VHF antenna located in respect to the location of the sonar?

There are two types of interference, conducted and radiated that can get into your sonar. Most likely it is conducted because as you indicated that the radio and the sonar are getting their respective power from the panel and it’s being feed from the battery some distance away. Most likely those power lines are being modulated when you key your radio, when your radio is transmitting; it draws much more power from the battery.

Solution for the radio with the assumption that the it draws about 8 amp: take a pair of wires size 10 or 12 depending on the results of the Wire Table, making sure that you use the round trip distant, take the red and black wires and twist them together by anchoring one end in a vise and the other end in the chuck of a drill, twist to 3 to 4 twist per inch there about. The reason for the twisting is counteract any interference that is picked up. The reason that you need a pair of wires is that you have to have an independent return line to the battery; what current goes up the red wire will come back on the black wire to the battery. If you only replaced the red wire, there is interference on the return wire that will get into your sonar. I selected the radio because it is the source of the problem. In addition, you could add a toroid near the radio to stop the interference from going down to the battery.

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Thanks for input guys. I will be getting on this right after XMAS. Hope all this warm weather hangs around for my project!

Proline I made a post on my Lake ontario site for this problem I have seen it posted before but couldn't find it so I'm hopeing I will get people to reply back I think every thing that was posted here will fix the problem.I'm just seeing if we missed anything.I will let you know.

Erin