Trolling motor and AM radio

[SWMuskeye]

When I fish late I like to listen to the Twins while I chase the elusive exclusive Muskellion. But every time my foot hits that pedal I get a high pitched wheezing sound out of my radio speakers. I don't think that it happens when it plays a cd or fm. Is there anything I can do to block this interference? Its getting pretty annoying and I'm talking about more than Bert Blyleven's commentary.

Thanks!

-MB

[Bushwacker]

I have the same exact problem. I put up with it for 4 hours on opener while listening to the Wild in the playoffs, but man is that annoying. Now I only turn on the Twins when I am anchored. Anybody know a solution?

[united jigsticker]

Sounds like you need an RF filter.

The only other solution would be to get a portable radio that runs off alkaline batteries.

Go Twins! Go!

------------------
Good fishing,
UJ
[email protected]

[This message has been edited by united jigsticker (edited 07-31-2003).]

[Guest]

If you are running a marine or automotive type head unit for a radio, there are interferance filters that plug in-line to the antenna cord (check radio shack). If the electrical systems are isolated, there shouldn't be any noise comming through the power system, then more than likely it is simple electro-mag interferance generated by the motor at the same frequency as the radio signal, or being inducted into the power cables, and there is not much you can do except tune into a different frequency or put up with it, short of sheilding the electrical systems, or perhaps an antenna booster?

[Iceman77]

The best thing to do is to try and segregate the electrical systems the best you can. If possible try to place the batteries on opposite sides of the transom and run the wiring for the trolling motor on the opposite side of the boat that the radio and it's electrical is run(i.e. make sure the trolling motor wires do not come close to the radio and its supply cables). Make sure you tuck all the wires under the boat metal. RF fields are line of sight types of induced current. If you obstruct the line of sight with grounded shielding this eliminates much of the RF fields induced current. Trolling motors do not produce high RF fields therefore it sounds to me like some of the cabling are too close together or the batteries may be to close together. RF currents can back feed down the cable and cause havoc with many instruments. As stated before their are RF filters on the market that can be used but I would make sure you obstruct the line of sight and segregate cabling as much as possible. The fact that you are picking this up on AM frequencies and not FM is due to the frequency of the current being induced onto the ground or +12V power line of the radio. Also make sure the antenna is not close to the trolling motor wiring and make sure the trolling motor cables and wiring are NOT coiled. Coils produce greater EMF's and RF fields. Coiling wires produces an antenna for transmitting undesireable RF fields.
Hope this helps you out some.
Russ

[catchin'whopper]

is the radio and trolling motor running off the same battery? if so, then the motor is creating the interference you hear. If you can get a separate smaller battery for the radio, it would eliminate it.

Comments from others?

-Catchin'

[SWMuskeye]

The radio is running off my starting battery. The trolling motor has its own battery. Anyone else have suggestions?

[chunkytrout]

coldone hit it on the head. On the AM side of things you will get noise especially with a magnetic field caused by an electric motor running. AM is suseptable to all types of interference. Take a portable radio and move as far from the source of the noise as possible (while remaining on the boat of course)

chunky