TM interference from hell

[PlayDoh]

So I had my GT54UHD on my TM (MK powerdrive) and after separating cables and such, I put the Ducer on the transom today. Sat in 34° heat doing so, which was a blast. I figured the ducer being on the TM was the problem since people have put rubber insulators between the 2 and had success.
amazingly I still have the same interference level I did with it on the transom. I’m at my wits end here. My ducer and sonar power cables are at least 2ft apart from the TM cables. My boat is aluminum so I’ve tried to keep all the sonar cables away from the hull. Kind of impossible to completely avoid the hull.
I have 3 large deep cycle batts up front. One at the bow tip area, and the other 2 in front of both consoles. The front / center and port batts are for the TM, and the starboard one is sonar. 106sv ultra btw, brand new. I don’t have a ground wire running to the gimbal mount, which is one of the few options I have left to try. I read connecting the TM and sonar battery grounds might help.
I'm out camping so I don’t have everything on hand, but I have lots. I do have the useless ferrite beads at the closest point on each cable, to the sonar unit. That make zero difference. I can set my gain to around 50% and avoid the interference for the most part, yet even at that level my display will go completely filled with interference at certain speeds. Full speed has no interference, and it’s not a ‘more power = more interference’ relation.

this and my lack luster SideVu has me second guessing my choice to go with Garmin. My HB units never got interference as long as the 2 wernt sharing the same batt, and the cables wernt literally touching. I was going to call Garmin but I was in one hell of a bad mood after ‘fishing’ for 3 hours. Trying to intermittently use the TM, read the sonar, deal with a wife and 2 kids under 10, and then my new $150 rod broke while trying to set the hook.

oh and twice I had to power off the unit because the touch screen became completely unresponsive. Twice in an hour. I was recording sonar and quick draw which I suspect is too much for it. I’m not sure why I’m even bothering recording the sonar since I can’t play it back with HomePort as it just crashes. It feels like it was part of Windows 98, it’s so clumsy and flawed.

My last resort is to wrap all the TM and sonar cables in tinfoil, and try the sonar at the stern 16ft away from the TM. I wouldn’t be the least bit surprised to see the same or worse interference.

Any help or suggestions are greatly appreciated.

[PlayDoh]

Oh, I have searched this and other sites for interference issues. I have a 3/4 in rubber block wrapped in tinfoil then gorilla tape for the TM mount, yet haven’t used it. I don’t recall seeing many transom mount interference issues with a bow mount TM.

[capt odie]

Dedicated sonar wiring helped my sonar system.
i would get clutter on screen when trolling motor made a power on then it would look fine.
heavy guage power and ground might help
i ran 8 guage wire ,tinned marine wire
the 8 guage was needed for the run length I have and eliminated volt drop

[BassTracker175]

Switch to Garmin Force! I have NO interference from it, even my LiveScope shares 24V power with it.

MK TMs seem PRODUCE lots of noises, based on the posts on BBC.

[BigBry]

If you haven’t tried this. Pop the top off the head and replace the blade fuse on the ground wire even if it still looks good. This worked for me after spending countless hours trying to isolate the source.

[Crappie Bob]

I ran into a crazy that sounds a lot like yours. I recently installed a second 93 SV at my steering console. The boat is 18 feet long. I have one at the front also on the trolling motor. The trolling motor mounted one Has it's own 8 gauge wire that runs from the single designated battery in the back of the boat along the left side to the front and attaches directly to the factory Garmin wire harness. The console mounted one has it's own designated 10 gauge wire going to the same battery in the back of the boat and that wire is run on the right side of the boat from the console to the seat and then across to the left side to the battery, and it is connected directly to the factory Garmin wiring harness.

The front transducer is on the foot of the trolling motor, and the rear transducer is on the back of the boat. Neither the transducer wires or the power wires of either unit is any where around each other. So, how in the hell when I step on the trolling motor pedal do I get the interference in the console unit?

I have decided that since it's an aluminum boat all the wire has to be run thru a concrete culvert to eliminate the noise. I have it almost gone at the front. I happened to look back at my console mount when stepping on the pedal and saw it. For the life of me I don't see how it is happening.

[PlayDoh]

I feel your pain bro. I think your right about the aluminum boat. I’ve never had the problem on older sonar units, and my TM was made in 2008. The same year and model that has the built-in ducer has ferrite rings built-in, and MK support suggests running a ground wire from the lower (motor) unit, up through the shaft and to the battery.
I feel like this is a major oversight on Garmins part. To ignore issues with the vastly most common TM and their products is foolish.

I just re-did my TM cables and shortened them up and eliminated the batt switch, just incase. I have a ton of tinfoil so I’ll try wrapping every cable with it. I might make a helmet out of it as well, Incase my brain waves create interference, lol. If I ran in tourneys I could just get close enough to others and ‘jam’ their sonar, lol.

I think the hull theory is the only one that makes any sense, or our TM are such ELectro-Magnetic polluters that they will need a lead case / housing to prevent interference. Considering our boats are one giant antenna / conductor, the problem is as worse as it gets.

[TomP.]

What has cleared up all my TM interference is run a ground wire from the skeg of my trolling motor to the ground of my starting battery. Any ground under the front deck that goes to the starting battery will work, every time I have changed trolling motors I now include this ground and have never had an interference issue, your mileage may vary but is has worked consistently for me.

[PlayDoh]

What has cleared up all my TM interference is run a ground wire from the skeg of my trolling motor to the ground of my starting battery. Any ground under the front deck that goes to the starting battery will work, every time I have changed trolling motors I now include this ground and have never had an interference issue, your mileage may vary but is has worked consistently for me.

do you run your sonar off the starting battery? I have a dedicated batt for the sonar, would that where I would run the skeg ground to?

I am getting a small amount of interference from I suspect the gas motor while the gain is set to auto-low. Perhaps I should run a common ground between the starting battery to my sonar battery as well.

thanks for the tip.

[PlayDoh]

Well another couple hours wasted. TM, sonar and boat all share a ground. Put a ground on / in the skeg of the TM and all that did jack. I found a decent write up from Vexilar on interference, and my guess is TM just produces too much EMI that I’m either going to have to shield it, or get rid of one of them. Not sure how I could insulate the motor, or if attempting to would end up being a total waste. Copper mesh? Lead + a jacket for it. Kryptonite?

[PlayDoh]

Here’s the link to good info
https://www.vexilar.com/blog/2018/10...r-interference

[BT Rig]

I have this same issue. Very disappointing as I added the garmin for future addition of LS and now I am afraid if I add LS it too will have interference. I run a combination of Humminbird, vexilar edge 3 and added the garmin this year. Only the garmin has interference. I have never had this issue on any boat or brand, even when I ran Lowrance. My transducers are all mounted on the transom, not the trolling motor. It’s crazy. Been searching the web and there does not seem to be a solution. Oh and My boat is fibreglass. I don’t think one should need to run ground wires and tin foil to try resolve interference, makes no sense. I share the pain......

[LWINCHESTER2]

BT Rig. Look at your frequencies. Vexilar is 107 and 400 kHz. Don't know what you are running on the Bird; probably 200 or chirp, SI 455, 800 or Mega. Garmin probably running chirp 2d and SI also. Try this. Set the Bird to 200 kHz only for 2d. The 83 kHz is a little too close the 107 on the Vexilar. Set the Bird SI/DI to 455 kHz. On the Garmin go into the 2d and set up manual frequencies. Add 150 kHz and 240 kHz. 150 will be the wider cone of the two. Either one should work. Then set the Garmin SI/DI to 800 kHz. You could reverse these with the Bird but one needs to be at around 800 and the other at 455. That should clean up any unit to unit interference. If the interference is coming from your TM that's another story altogether.

[BT Rig]

BT Rig. Look at your frequencies. Vexilar is 107 and 400 kHz. Don't know what you are running on the Bird; probably 200 or chirp, SI 455, 800 or Mega. Garmin probably running chirp 2d and SI also. Try this. Set the Bird to 200 kHz only for 2d. The 83 kHz is a little too close the 107 on the Vexilar. Set the Bird SI/DI to 455 kHz. On the Garmin go into the 2d and set up manual frequencies. Add 150 kHz and 240 kHz. 150 will be the wider cone of the two. Either one should work. Then set the Garmin SI/DI to 800 kHz. You could reverse these with the Bird but one needs to be at around 800 and the other at 455. That should clean up any unit to unit interference. If the interference is coming from your TM that's another story altogether.

Larry,
must be a trolling motor issue. I get the interference on the garmin with every other unit shut off. I have even unplugged the power and transducer cables from all the other units ( not that it should matter ��) to no avail. The only thing I can see potentially tying the trolling motor to the garmin would be the fact all 4 batteries are connected to a 4 bank charger. But again, I have never experienced this before. Thanks for the info on frequencies.

[PlayDoh]

The charger could be a partial culprit. Yet the fact the Garmin is effected and not the other 2, makes that unlikely to be the only source.
what TM do you have? Since 2013 MK seemed to deal with the interference issue to an extent.

What’s puzzling for me on my boat is how having the TD mounted on the transom or TM makes no difference. That seems to suggest it’s the sonars power cable that’s picking up the interference and not the TD.

[PlayDoh]

I can find EMI RFI shielding cable sleeves or wrap online, but it’s not cheap. It’s not crazy expensive either, like $200 for 50ft of 1/2in. Yet it’s copper mesh. I’m thinking copper pipe would not only work way better but a heck of a lot cheaper. At least even to just test the idea. I have some copper tape from another task. I got some and used it to shield my Gopro from the internal Wifi antenna, which was causing audible noise on recordings.
I could plumb a line from the bow deck to the battery, then use the tape where the cable goes above the deck for esthetic basically.

[weaponofbassdestruction]

I don’t have an issue with interference however I’m working on tweaking the picture for the best performance. Have you guys ran a water ground from your black box and unit cradle? This should direct the field towards the water. I’m no electrical guru but in theory this should help the problem. I thought about running it to trolling motor skeg or strapping a ground bar to the trolling motor shaft but this keeps the interference in the same area as the majority of the problem. I’m thinking it would help to run a dedicated ground wire to the transom and connecting it to something metal underwater back there. Does this sound ridiculous? I do understand all the Garmin units may not have this option but I know the black box we all have does.

[PlayDoh]

I think I got it licked. “Think” because I only had 1/2 an hour at most on the water when a wicked storm hit.

Things I did today were, removed the ground wire from trolling motor batts to sonar batt. Added a 18 ga wire ground to the boat / hull (and water via Aluminum hull re; Weapon’s idea) and put the trolling motor skeg ground wire to the sonar batt. Oh and I added the 2 extra ferrite beads to the sonar power cable (now 3 on power, 1 on TD cable at gimbal mount end).

I left the ground wire from the starting batt to sonar batt connected. I read that Aluminum boats should have a ‘bonding strip’ which is a think wire or strap from hull to batt ground. Found that on a Garmin support article.

Most aluminum hulls have a bonding strip that is bolted down to the hull of the boat while the other is connected to the boat's battery ground. If the boat has this, find and remove it to check for corrosion as well as to make sure this bonding strip is completely clean. It can be cleaned by using a wire brush and some spray. 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 had zero interference while using the trolling motor today. I cranked the gain up as well. I also tilted the TD a bit more down at the rear. Seemed to help with my motor leg blocking the SI, yet my DI seemed like it wasn’t working great. I’ll try one notch back up tomorrow as I went 2 down from where I was.

Woohoo (fingers crossed)

[swamprat]

IT does suck,I have about given the frack up.I have a glass boat,Side view sucks,not as bad,It has something to do with the maximizer.Mine works perfect on high speed, or off...In between at any speed sucks

[PlayDoh]

What is a “maximizer”? Trolling motor feature? If so your correct, it’s called PWM (Pulse Width Modulation), and they all use it. If you read up on it, you can figure it out like I did.
here’s another link.
https://www.humminbird.com/support/f...orInterference

https://support.garmin.com/en-ZA/?fa...HT7uepgGXzKlMA

Don’t give up. I’d normally suggest calling Garmin but I called twice yesterday and left my number for their call back and they never called back. I’d imagine their swamped with calls from the outage and it being Monday but the thing said the expected wait time was just over an hour.