2 electronics problems

[drag4striper]

I have two hummingbirds units that came on my boat. The one on the bow has a trolling motor mounted transducer and the one on the console has a thru hull transducer. I'm having trouble with both. So I was hoping some of the electronics Guru's might have some input. The bow unit has major interference when the trolling motor is on, no matter how low the sensitivity setting is. When the T/M is off it is fine. Do they make some type of a filter for that? The unit on the console looks great when I have it in the setup simulator mode, but on the water it is just not right. I was thinking maybe a bad thru hull transducer. I don't know who installed these units......... jackleg or pro so any input would be helpful.

[formula180]

The through the hull transducer needs a clear area and water around it.

You need a filter on the DC power to the TM and/or run separate lines. Here is a line filter you can get a Radio Shack

comingsoon.radioshack.com/radioshack-snap-together-ferrite-choke-core/2730105.html

[Deleted]

Thru halls are tricky. Some boats just don't work well with them. Some issues include: air pockets in the fiberglass, turbulence below the ducer while running and air in the epoxy used to mount. I would switch to a transom mount. I would also get another ducer and hook it up and just put it in the water to make sure my unit is good before installing.

In terms of the interference...good luck with that. There is a load of info in this section that discusses how to get rid of interference. I grounded my motor to my TM battery to clear my interference.

[drag4striper]

Thank you gentlemen for your input. I didn't research the older post before asking. Not realizing so many had these type problems. I tend to get tunnel vision thinking I am the only one. 

[mwardncsu]

Any pics of the interference you are seeing? Based on what you are saying it sounds like Trolling motor induced, but of course if you run both units at the same time on the same frequency you are going to get interference as well.


Chasing the interference and solving it is a bit of black magic, but taking a methodical approach, changing one thing at a time and seeing the result, it the way to chase it down. The most common culprits are induced noise from other circuits (specifically your TM or pumps). Avoid running the power wires for the electronics in parallel to other wiring. Also separate the power wires and the xducer wire for the sonar as much as possible. Spiraling the positive and negative wiring of the supply wires can help to prevent coupled noise.

Power your electronics off a battery other than your trolling motor battery - you may find you need to ground your TM like Yam and I did ( smlfishingforums.proboards.com/thread/2613/sonar-interference-riptide-info ) - and then connect the grounds between the trolling motor battery (if it is a 24 or 36V, then using whichiever ground from the one terminal you have the TM ground wire connected to), to the ground of your other batteries (use a small 3A or so fuse on this wire).


Using an ferrite coil like mentioned is a good idea. You might try some of the smaller ones a few places. Humminbird has a "kit" - to use on the trolling motor to help suppress noise (basically its a choke coil)- www.humminbird.com/Products/TMC-1/


A lot of times just cleaning up your wiring will solve the issue...... just take it step at a time and tackle it.