What do I have going on here?

[shane23ss]

Helix 10 DI on the bow. When the trolling motor is on I get this. Transducer cable is not ran down any cables on the trolling motor, power and ground is dedicated run to the cranking battery, and I also have a ground running down to a screw on the Transducer Shield and Saver. I had this exact same set-up on my other boat with 899's and had no problems. You can only see it in DI. (Just to be clear, I'm not talking about the "cross-talk" you see from the transducer of my other Helix 10 being on, I'm talking about the "haze" look). Thanks.

[ezfishn]

That is RFI from the TM. Which transducer did you install on TM?

[shane23ss]

It has the factory transducer on a Transducer Shield & Saver. Whats causing the RFI? Like I stated, I have the exact same set-up on my other boat on my 899's

[Wayne P.]

Your trolling motor is broadcasting on the Imaging frequency. That is called RFI--Radio Frequency Interference.

The proper trolling motor DI transducer is a trolling motor PUCK. It has extra internal shielding that the transom version does not have.

There are two choices for a PUCK
XTM 9 DI 25 T is tuned to the same frequencies as the transom transducer
XTM 9 WIDE DI 20 T is tuned to 83/200 kHz 2D sonar.

You don't have the exact set-up with both boats. Each installation is unique.

[shane23ss]

You don't have the exact set-up with both boats. Each installation is unique.

Then there is no way to fix it. Each installation being unique, and not like any other, would mean it's just trial and error anytime you install one.

[sfw1960]

No RFI cure is always the same.

[Wayne P.]

Then there is no way to fix it. Each installation being unique, and not like any other, would mean it's just trial and error anytime you install one.

Yes there is a way to fix it. BUT there is no way to know what to fix ahead of time since it is random in occurrence and the affected frequency.
Yes EVERY installation is unique and only after installation would anyone know it there will be an issue.
It can occur with any brand/model of motor, with any brand/model of sonar unit on any craft.
If it was entirely preventable, that would have been done over 40 years ago.

Contact Humminbird Customer Service for help with that issue.

[ezfishn]

It has the factory transducer on a Transducer Shield & Saver. Whats causing the RFI? Like I stated, I have the exact same set-up on my other boat on my 899's

Which transducer were you using with the 899? They normally use either a compact or HDSI transducer and both have the extra shielding... if not mistaken. That may have been the reason you didn't get RFI from the TM. Even with the correct cables, you can still have problems. It's best to take one step at a time in order to isolate the problem and correct it because it may take several solutions to stop it.

[shane23ss]

Which transducer were you using with the 899? They normally use either a compact or HDSI transducer and both have the extra shielding... if not mistaken. That may have been the reason you didn't get RFI from the TM. Even with the correct cables, you can still have problems. It's best to take one step at a time in order to isolate the problem and correct it because it may take several solutions to stop it.

It has the Compact that came with the 899 on a Transducer Shield & Saver. I upgraded the back one to HDSI

[Wayne P.]

It has the Compact that came with the 899 on a Transducer Shield & Saver. I upgraded the back one to HDSI

The Compact SI transom transducer XNT 9 SI 180 T does not have the extra internal shielding. The trolling motor Compact SI PUCK does--XTM 9 SI 180 T. The HDSI has the extra internal shielding also.

Since you did not use the proper one for the bow 899 that does have the extra internal shielding, that motor does not interfere with the 899 that is on the bow and does not need a shielded transducer----YET. As the motor wears with use, it may.

[wtaylor418]

Wayne, you are really, really knowledgeable! How did you learn so much about the Humminbirds? Did the factory school you, or is it just experience? Or, a retired Navy Sonar Tech.?? :)

[sfw1960]

Wayne prides himself on knowing what he is talking about instead of guessing!

The man has legions of experience ~ the kind that baffles many...LOL

[Choothim]

Your trolling motor is broadcasting on the Imaging frequency. That is called RFI--Radio Frequency Interference.

The proper trolling motor DI transducer is a trolling motor PUCK. It has extra internal shielding that the transom version does not have.

There are two choices for a PUCK
XTM 9 DI 25 T is tuned to the same frequencies as the transom transducer
XTM 9 WIDE DI 20 T is tuned to 83/200 kHz 2D sonar.

You don't have the exact set-up with both boats. Each installation is unique.

Hey Wayne, how is it that we can take the unit off the boat, book it to a battery outside the boat, when you turn the trolling motor on it still causes interference on the unit. This is going on with a bass cat right now. The trolling motor has no transducer on it and the unit is completely out of the boat with its on power source.

[Bob B]

RF interference has many paths .... If you have nothing connected to the unit except the external battery, the path has to be transmission through the air like a radio wave.....the trolling motor must be VERY noisy.

[Choothim]

As far as I know, it's only happening on motorguide.

[Wayne P.]

As far as I know, it's only happening on motorguide.

RFI can come from any trolling motor brand or model. Lots of complaints about Minnkota's also. One of the first items suggested to check with Minnkota is the fuse in the top cap.

With an electric steer motor, there is another motor that can cause RFI issues.