Interference, ferrite chokes anyone use them?

[Minnie Man]

Hey guys planning out the wiring for a new hds 12 this spring. Plan to do a dedicated power wire this year. My engine power, graph power, and ducer cables all run down the same gunwale and are likely closer to each other than what is ideal. Anyone have experience with chokes or shielding of some kind to help with interference?

Thanks.

Sent from my SM-G973U using Tapatalk

[kliph]

I have used them. Never saw a deference.
Give it a try and see what you think.
Good luck.

[clawman]

On my last boat I had a Motorguide so had lots of interference. I had chokes on about every wire in the boat and they did help but not eliminate the interference. They are pretty cheap on eBay.

[Ltrain]

I use the barrel clipons but you might want to get the humminbird ferrite ring and give it a good 6 loops through( pic attached), the more the better. Wouldn't hurt to do it on TM wires too

[TomP.]

On the console or trolling motor? Console is usually not an issue for me on the trolling motor best luck I have had is run a ground wire from the skeg of the trolling motor to the starting battery ground. Any ground under the front deck that goes to the starting battery will work. Since I have started running this ground have never had an issue with interference from the trolling motor.

[David Anderson]

Originally Posted by clawman

On my last boat I had a Motorguide so had lots of interference. I had chokes on about every wire in the boat and they did help but not eliminate the interference. They are pretty cheap on eBay.

FWIW, I designed magnetic components for the last 44 years. There are 2 types of ferrite, one is low permeability (less than 750 perm) ferrite that has high core loss characteristics and those are typically used in shield bead configurations where you have a core that snaps around a cable. The core around the wire creates a little inductance and because inductance opposes any change in current, when a spike (Interference) comes down the line from say the brushes in a motor, the core will basically absorb that spike. Usually these types of noise suppression cores work only on higher frequency noise because of the small amount of inductance created by the core/single turn. The other is high permeability toroid cores (greater than 5000 perm) which are typically used where one wraps the wire around the core a number of times. This substantially increases the inline inductance which tends to be good for lower frequency noise. The higher the perm, the more inductance per turn. Lower perm toroids may not be very effective unless one adds a lot of turns, and are not used in typical applications like this, but again depending on the frequency of the noise, it could work. In the end it matters what frequency the noise is. One may need both, a shield bead type for the high frequency noise and then a higher perm toroid with a number of wraps around the core to stop the lower frequency noise). Pretty much anything that is using a switching power supply like your computer has these to assure that the switching noise isn't screwing up your TV or other electronic equipment, as the FCC dictates this. One of the preferred methodology is to use a common mode choke at the point where the power is hooked up closest to the device causing the noise. It is a high perm toroid with 2 winding's, one connected in series with the power wire and the other connected in series to the ground. The winding's are wound separately, one on one half and the exact winding on the other half, a method to keep the interewinding capacitance to a minimum(which in itself can cause problems, especially in higher frequency noise). Also because of the polarity of a common mode choke, the separate winding's on the core and in the power/ground try to cancel each other out and can be very effective. Minnie Man is right to be concerned however I would run them all first before assuming there is an issue.

[Minnie Man]

Originally Posted by David Anderson

FWIW, I designed magnetic components for the last 44 years. There are 2 types of ferrite, one is low permeability (less than 750 perm) ferrite that has high core loss characteristics and those are typically used in shield bead configurations where you have a core that snaps around a cable. The core around the wire creates a little inductance and because inductance opposes any change in current, when a spike (Interference) comes down the line from say the brushes in a motor, the core will basically absorb that spike. Usually these types of noise suppression cores work only on higher frequency noise because of the small amount of inductance created by the core/single turn. The other is high permeability toroid cores (greater than 5000 perm) which are typically used where one wraps the wire around the core a number of times. This substantially increases the inline inductance which tends to be good for lower frequency noise. The higher the perm, the more inductance per turn. Lower perm toroids may not be very effective unless one adds a lot of turns, and are not used in typical applications like this, but again depending on the frequency of the noise, it could work. In the end it matters what frequency the noise is. One may need both, a shield bead type for the high frequency noise and then a higher perm toroid with a number of wraps around the core to stop the lower frequency noise). Pretty much anything that is using a switching power supply like your computer has these to assure that the switching noise isn't screwing up your TV or other electronic equipment, as the FCC dictates this. One of the preferred methodology is to use a common mode choke at the point where the power is hooked up closest to the device causing the noise. It is a high perm toroid with 2 winding's, one connected in series with the power wire and the other connected in series to the ground. The winding's are wound separately, one on one half and the exact winding on the other half, a method to keep the interewinding capacitance to a minimum(which in itself can cause problems, especially in higher frequency noise). Also because of the polarity of a common mode choke, the separate winding's on the core and in the power/ground try to cancel each other out and can be very effective. Minnie Man is right to be concerned however I would run them all first before assuming there is an issue.

Wow. David, we should have a drink at Brindleys on the opener and talk about this. I'm the guy in the black reata each year, you are in the big cabin right and the ranger right? I think we have met in the past, you guys have a whole crew of guys.

Step one for me is dedicated power to my units. Is there a better way to run the downscan and sonar cables than just down the starboard gunwale? I snake mine through the same path as all the other rigging. There is NMEA, power, throttle, sonar, structure, everything in that run...

I have noticed trolling motor interference at the front graph, but don't spend enough time up there to be mad about it. I should investigate it further. Need ice off these lakes!

Sent from my SM-G973U using Tapatalk

[David Anderson]

Originally Posted by Minnie Man

Wow. David, we should have a drink at Brindleys on the opener and talk about this. I'm the guy in the black reata each year, you are in the big cabin right and the ranger right? I think we have met in the past, you guys have a whole crew of guys.

Step one for me is dedicated power to my units. Is there a better way to run the downscan and sonar cables than just down the starboard gunwale? I snake mine through the same path as all the other rigging. There is NMEA, power, throttle, sonar, structure, everything in that run...

I have noticed trolling motor interference at the front graph, but don't spend enough time up there to be mad about it. I should investigate it further. Need ice off these lakes!

Sent from my SM-G973U using Tapatalk

Definitely stop by as we are all set for our 47th Annual Leech Lake Opener, hat's are ordered, deposit taken care of, just 11 weeks now! As well there will be plenty of refreshments that might help you to understand the technical aspect better:-) Ice out should be early because there isn't much. The transducer cable and the NMEA cables should be shielded cable for that reason and should not cause a problem. All my cables are run in the standard conduit that Ranger has installed in the boat for that reason and I have zero issues. PM me and maybe I can get some toroids for you to try. Look forward to seeing you at Brindley's

[bbheli]

Ferrit toroids and Cocktails - Now there is a thing you don't do every day LOL but I'm down!

[Yellow Fever]

one thing that may help is to put twists or transpositions in the wire you are going to use ( simply its weaving the wires around each other ) This will eliminate having the wires in parallel to other wires in the conduit...this is the difference in telephone/data cabling ie the higher speed wire has more twists. I use marine wire in my installs and it really puzzles me that the pairs are side by side and not twisted, so i lay my wire out and secure one end and proceed to put twists in it. Hope this helped and good luck