TM interference from hell

[PlayDoh]

I forgot to mention that I completely wrapped my sonar power cable In tinfoil. With extra attention to the splices near the battery. I wrapped it a couple times, then took long pieces and folded them, then wrapped those lengthwise on the cable and did my best to scrunch it around. Then I partially wrapped the foil with tape. I made sure there were no gaps. I’m somewhat doubtful that was the solution, yet at the same time it’s certainly shielding the cable, which is a common method of dealing with EMI. The shielding should be grounded, but I didn’t do that.
Also be careful with the foil around the battery. I got a little sloppy and shorted out the battery for a split second. I’d like to make battery boxes, or buy some and line them with Aluminum or something. Yet that’s getting a bit carried away I suppose.

[swamprat]

Maximizer is Minkota's old trade name for their P.W.M. They used the name for years.... Oh yea thanks for the links I will check them out.

[Slim95]

I have had Interference issues from my minnkota Ultrex MDI on my Helix for the better part of a year up until recently. I had crazy interference everytime the TM turned and ever time we stepped on the pedal. After what I did listed below my unit is perfectly clear with no adjustment on the Helix. I cant say what I have done will work for you but if you have not tried anything I listed and shown below then give it a shot. Below is the message I sent to a fellow member who asked how I eliminated my interference. My apologies on the long message




Ok so I have tried everything under the sun to fix the interference on my Ultrex 112 MDI I-pilot link. I have narrowed it down to a few points listed below. Also listed below is the pictures I took of the Ferrite rings I installed on the factory power wires coming into the foot pedal from the battery. Also below are the two part numbers from the humminbird parts website that I installed in the Ultrex head unit that I think are the major factors of the elimination of the RFI/EMI. I would love to know if this works for you so please update me if you try this. I have tried many more things than what I am listing below but I dont think they had much of an impact in the elimination of the RFI/EMI interference.

1. I wrapped the power cord coming into the trolling motor around a double stacked Torrid 77 rings as shown below in the picture. BTW please excuse the wiring mess, this was just for testing
http://<a href="https://postimages.o...[/img]</a>
[IMG][/IMG]

2. I installed two ferrite rings over the power chord in the ultrex head unit. The MALE spade terminals on the power chord will not slide thru the ferrite ring/cylinder without trimming a small amount on the side of the MALE spade terminal. BTW I twist ALL power cords when ever I can. I do not know what the type of ferrite it is from Humminbird I just have the part numbers. Im not sure if it matters but try and duplicate the power wire and the transducer wire layout in the picture.
[IMG][/IMG]
Below are the part numbers for the two different ferrite cylinders I installed in the Ultrex Head

BEAD-FERRITE / INSTRUCTION KIT
2887313
Qty Shipped: 1 Each
Unit Price: $9.26 BEAD-FERRITE 2307312 Qty Shipped: 1 Each Unit Price: $0.95 3. The last thing that I think had a factor in eliminating the RFI/EMI was running a true dedicated 12ga twisted pair from the battery to the head unit. The power wire I used I got off ebay and is a true MILSPEC shielded twisted pair. I solder sleeved shielded the power wire at both ends but I grounded the the wire shield at the battery. Here is the wire I used from ebay. M27500-12SB2T23-Mil Spec Cable TWISTED SHIELDED, 2 CONDUCTOR, 12 AWG. Im not sure if it makes a difference but I like the insurance of using adhesive lined heat shrink on all open terminals and I use all deutsch connectors with crimped contacts on all of m,y wire connections if space is not a problem. 4. I took out the original 3amp fuse in the ultrex head out and replaced it with a new 3amp fuse from littelfuse. The original fuse was not blown or damaged I was just trying to eliminate every variable I could. 5. I also restored defaults the night before we went out to test. I wish I would not have done this because I feel like this might have altered the back to back testing I was trying to perform. I am only sharing this as this was one of the things I did the day before the trip and we had zero interference on the trip.

[Crappie Bob]

Well the weirdest thing happened to day. I went out again to make sure my 93sv was fine before sending the other one back to Garmin.
I had full intentions on doing this === If the boat does not have a bonding strip, create one by using a jumper cable, attaching one end to a solid secure point of the boat and the other to the boat's battery ground.


I left in such a hurry I forgot all about it. I got to the lake and figured I would fish and fix it later. The weird thing is, absolutely no interference on either of the 93sv units where as before they both had it. For the life of me I can't grasp this stuff. How can it have interference in one lake and not another, unless bottom texture has an input on it. I do know the lake I was at today is the only lake the Fish Eye 3D works in as far as where I have tried it so far. I absolutely have no idea what the difference is. If I only fish in the one lake my Garmin stuff is top of the line, no faults at all. Brag on it all day, go somewhere else, and piss on it all day, never ends. I'm just going to send the second unit back to them, buy a big bag of medicine, and go to my hunt camp for a week


I am going to try that "double stacked Torrid 77 rings" thing if I can find the room up front, looks like a good idea

[PlayDoh]

Awesome write up slim. Great info. I think that type of ferrite ring is referred to as a ‘choke’.

[PlayDoh]

I noticed a big difference in the amount of interference I was getting at 2 different sides of the lake I was fishing. Deeper hard bottom gave more interference. Shallow, sandy bottom was less. That made me suspect the ‘bonding strip’ effect, since it seems the ground / lake bottom was absorbing some of the interference / EMI/RFI and the hard was reflecting more.

I suspect my grounding the sonar batt to the boat and thereby the water via tin hull, and my grounding my TM skeg to the sonar batt did the trick.

the last couple times I was out, my DI / ClearVu was displaying a line at mid depth at the launch, which is 8ft deep and all rock. It’s inside a large rock wave-break which could mean large amounts of reflection.

[Crappie Bob]

What if we took 40 or 50 feet of 6 ga wire and attached 6 feet of 3/8 chain to one end and attached the other end to the transom and drag it behind us while we fish, you think that would be ground enough

[Crappie Bob]

Went out today fishing for a while and testing the interference remedies. The whole time I have had my boat, Tracker 185 I have been trying to UN-ground it. The reason was I was all wet from sweat one day and leaned over the back side with my chest on the rail and touched the positive post on the battery and felt like I was almost electrocuted. After I came to my wits I decided that had to be fixed.

Well who would have thunk, that was what started some of my problems with my Garmin.

I put a 6 gauge battery cable from the NEG on my Garmin battery where both Garmins are hooked up to my NEG on my starting battery, and then another 6 gauge cable from the NEG on my starting battery to the transom brace and screwed it to that, for ground.

All day I saw 1 tiny instance of interference in the 2d sonar on either unit, just barely spiked not all the way to the top like usual, none in the Down-Vue and just a little at times in the Side-Vue, depending on where I was in the lake. But all in all if you had never seen it to start with you would never had know it was even there.

So then I decided to take the 9 ferrite chokes off all the transducer and power wires to see what happened. The ferrite beads being off didn't change a thing, so they went in the junk drawer. I wish I had done that 6 months ago, I will just have to remember DO NOT TOUCH THE POSITIVE BATTERY POST WHILE LEANING OVER THE BOAT SIDE

I guess I can take the 12 pounds of tin foil off next, after I check it in one more lake but I actually think the interference is gone for good. If you haven't done that ground thing yet you have to try it. I took a set of small jumper cables I keep in the back to try it on the water and when it worked I hard wired it all. Hope this helps somebody else with the same problems, worked for me.....

[PlayDoh]

Awesome to hear Bob. After all this I’m wondering why all the sonar brands don’t put together a better summary of these fixes. Why I had to Google fu for a couple days when I’m sure if a Garmin tech could have actually called me back, would have known instantly what to do.
Oh well I suppose. I know I learned a heck of a lot more about EFI, RFI and the like than I did last week

[Crappie Bob]

I don't know either, you would think a 6 x 18 piece of aluminum floating in the water is about as grounded as it gets, but who knows
I would never have dreamed you had to ground everything to the boat because its aluminum t eliminate the interference. All my previous boats were glass and never had this problem with them. Oh well, you never get to old to learn

Hope you get yours going also

[PlayDoh]

I fixed mine a few days ago. Crystal clear at any gain.
These trolling motors are EFI megaphones, and considering we’re putting a 10 pound or more magneto in the water it makes sense. I think it’s the hull that essentially acts like an antenna and makes the problem only worse. Grounding the sonar batt allows the interference charge (EFI) get absorbed by the battery and not everything else in the boat. CHIRP employs a wide array of frequencies which is likely why none of my previous sonars were effected. Or perhaps they were and just didn’t display the interference as visible noise.

[Crappie Bob]

Dang, we may be on to something - or on something

I hope all read this that have interference problems before they trash their equipment