Unknown Interference

Hello,

I live in Michigan and recently added a GPS 1022, Livescope, GCV 20 black box with a GT34UHD on the barrel of an Ultrex. Prior to these additions I had a PSS22, GPS 1242 with a 52 transducer mounted on the barrel. At the console I have a GPS 1042 and they are linked with the network cable. Prior to starting the new additions, I ran 12 gauge marine wire from the fuse box under the console to the bow to wire the new graph along with hook the existing 1242 to the new wire and connect both new black boxes to the 12 gauge wire and installed them on their own circuit under the console. All inline fuses were left in place and a good connection was in place to the factory wiring when connecting to the new 12ga marine wire. I upgraded to a 31 Opti blue top battery to help support the new graph and boxes. Currently the PS22 is not hooked up(waiting on the connector since the 13ft stock wasn't long enough).

Here is the issue after the brief summary. As mentioned, I live in Michigan so we still have hard water for testing. My son fished in the BASS Highschool open on Hartwell last weekend and I had everything hooked up and ready to go for the trip. Once we got on the lake I noticed a lot of interference that I never had before. The pictures show. When the Ultrex is in use the graphs are really not even usable. My GT15 and 30 at the transoms are fine. I adjusted everything possible, separated all the wires to see if one in particular was the culprit with no luck. As you could guess, we were bummed. The Livescope seemed to work decent with some interference, but nothing like Clear, SideVu or traditional view.

We made do and the boys were able to put together a 5 fish bag for their first time on that lake. I called Garmin first thing Monday morning and had a great rep on the phone named Quincy. He suggested the ferrite insulators along with ferrite tape. I was able to locate the tape about an hour away today and paid $65 dollars for a roll only to find out that it won't stick if wet. The ferrite insulators will be here tomorrow. Quincy also suggested that I separate the transducer cable and route it away from the network or any other pre existing cables. Today I did that before trying anything else. I even separated them completely from the trolling motor and any other contact spots. Both black boxes are mounted in the rod locker in front of the console.

Basically at this point, I am a real nervous and concerned as you can imagine. My plans are to add the ferrite insulators in as many spots and cables as needed, re run all the wire into its own circuit box, add a 5th battery to support the graphs and keep my fingers crossed. I have to have this fixed and ready to go prior to the end of the month when we leave for Guntersville for stop 2 of the highschool open. I doubt we will have any open water to confirm that the problem is fixed.

I am willing to make a drive or give my phone number to anyone that has information to help. Thanks for reading and helping! Jeff

I take it that since the GT34 is on the torpedo that you removed the GT52.
I wasn't clear on when you were getting the interference. Was it non-stop or when you used the trolling motor?
The UHD is very high frequency and the higher frequencies are more sensitive to TM effects.
Fixing interference like this is pretty much a trial and error process and the testing to see if something worked has to be on-the-water testing.
You can do some testing in the garage by seeing if triggering the TM causes spikes on the screen but you won't know for sure until you are on the water.
The ferrites have fixed it for quite a few people. Maybe it will for you.
Some people report that running an extra ground to the fin of the TM helps.
Wish I could offer more.

Yes, I removed the 52. I was trying to give a description that would help eliminate when and where the problem may have started. The interference is at its worst is when the trolling motor is engaged. You can see some when the power is on but the second the blades are engaged the interference is severe. The first picture shows the breaks in between when the motor is engaged. I was told that there is a ground fuse in the head of the Ultrex that can cause issues. This reminds me of having an old car and replacing every part to find the issue. I’m hoping someone has those magic words on where and what to start with. Thanks!

I'm no expert on this and I'll be glad to defer to someone else who knows more when/if they jump in.

Have a look at these to see if they give any insights. They are Humminbird but brand doesn't matter.

https://www.youtube.com/watch?v=6lwdXDgJ2f8

https://www.youtube.com/watch?v=8p8NJ0LvNpo

Thanks, I watched these earlier and had no idea about the fuse inside the Ultrex head. I will be sure to check that tomorrow. As far as grounding the TM, I read that it’s a big no no for the Ultrex. Makes to much sense not to try though. Also, grounding the both the LS box and the HD box. Graphs also have a place for a grounding wire. I’ve never had to use these in the past or heard of anyone on a bass boat. Garmin suggested these are for large boats with multiple accessories. I’m wondering if I run a ground wire back to a battery or empty spot on the fuse box? I’ll take any info, suggestions or tips. Thanks!

Another one of a few dozen possible remedies for RFI that may or may not work:

http://www.bbcboards.net/showthread.php?t=250494

Probably not what you want to hear but I was running my sonar on a 1242 from the built in transducer on my Ultrex. Major interference while the HB unit running a transducer on the bottom of the motor was clear. Just for curiosity I hooked the HB unit into the same built in transducer and it was clear also. Apparently the garmin is picking up rfi the HB is filtering out. My Livescope is clear however.