FM Radio Interference

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05-24-2011, 08:36 AM
prefers shiners

Trolling Motor/AM/FM Radio Interference

My Triton F & S came with a an AM/FM/Sirius ready radio....from the beginning it always has static on the radio when I run the trolling motor...I assumed it was because it was probably connected to the (2) trolling motor batteries....while in for yearly maintenance I asked my boat repairmen to connect it to the cranking battery....when I picked it up he said nothing was done because no matter which battery it was connected to it would always have the static when running the TM due to them being on the same "frequency"?????.....I am no electrical genius but this just doesn't sound right to me....is this correct or is it he just did not want to fool with it.....other than that, I have complete confidence in this repair shop......this was only one person who works there.....thanks for any help.....
05-24-2011, 11:20 AM
Bombfixer

I could see perhaps some bleed over from the trolling on certain AM stations due to frequency overlap, but not FM stations above 89-90 range. Now if you have a remote control TM then there may be an issue. Another idea is that TM is acting as a "White Noise Generator" but if that was the case, you would get interference on your FF as well as AM/FM. Another culprit might be the location of the Radio antenna. Radio Shack might have a filter kit that you could put on the AM/FM, either the antenna or the power wires.
05-24-2011, 12:07 PM
CatFan

I'd expect trouble with the brushes on AM, but not so much FM. If it has an external port for an MP3 player, try that to help figure out if the interference is coming in from the antenna port or power leads. Is the TM variable or 5-speed?
05-25-2011, 10:30 AM
prefers shiners

Quote:

Originally Posted by CatFan

I'd expect trouble with the brushes on AM, but not so much FM. If it has an external port for an MP3 player, try that to help figure out if the interference is coming in from the antenna port or power leads. Is the TM variable or 5-speed?

my wife runs the radio....she said interference on AM only.....TM is variable speed.....antennae is just a simple wire type laying beside the feed to the TM.....I tried one of those 18" whips but it was worse reception....I will try the plug in from an external sourse.....then look into a filter.....I forgot to mention that I believe the radio is wired to the cranking battery because the repairman left the radio on and it ran down my new cranking battery....thanks for the help.....
05-25-2011, 10:45 AM
CatFan

I suspect you won't find anything that works on reducing the AM noise. FM is chosen for a lot of communication purposes because it is noise resistant compared to AM. The brushes riding on the commutator make a decent amount of electrical noise that is broadcast over the air. The only solutions that will gain you much of anything are shielding the radio and moving the antenna and/or radio away from the TM.
05-25-2011, 01:11 PM
prefers shiners

Quote:

Originally Posted by CatFan

I suspect you won't find anything that works on reducing the AM noise. FM is chosen for a lot of communication purposes because it is noise resistant compared to AM. The brushes riding on the commutator make a decent amount of electrical noise that is broadcast over the air. The only solutions that will gain you much of anything are shielding the radio and moving the antenna and/or radio away from the TM.

thanks again Catfan....looks like she will have to do without her AM "talk shows"....moving the radio is not an option....I see you are an EE...I retired from engineering last year after 55 years in the business....I am a Civil/Structural drawing checker....we primarily designed oil refineries and chemical plants...
05-26-2011, 06:40 AM
CatFan

Quote:

Originally Posted by prefers shiners

thanks again Catfan....looks like she will have to do without her AM "talk shows"....moving the radio is not an option....I see you are an EE...I retired from engineering last year after 55 years in the business....I am a Civil/Structural drawing checker....we primarily designed oil refineries and chemical plants...

They just don't make many good quality AM radios anymore. These guys handle some good quality AM portables that might be more noise resistant.

Interesting that you were in that business. One of the things that steered me toward engineering as a child was watching the construction and operation of a plant that Dupont built in Louisville. I was amazed by the intricacy and accuracy. I picked a different field, but it planted the seed.
05-26-2011, 06:46 PM
Good Stuff

Not to derail the thread but I am having the same problem with my I-Pilot and my VHF. Any thought for a fix?
05-26-2011, 06:53 PM
prefers shiners

Quote:

Originally Posted by Good Stuff

Not to derail the thread but I am having the same problem with my I-Pilot and my VHF. Any thought for a fix?

no problem GS......jump right in....I can't help you but these guys seem to know their stuff so maybe they can help you....
05-26-2011, 08:50 PM
CatFan

Quote:

Originally Posted by Good Stuff

Not to derail the thread but I am having the same problem with my I-Pilot and my VHF. Any thought for a fix?

Is it a motor noise or is it when you use the remote or the motor makes a steering correction?