Eliminating InterferenceEliminating Interference Do you have interference between the trolling motor and the electronics? What causes interference and can you do about it?
By Don Iovino
The mechanical side of angling is more important than some people think. Boat, motor, and electronic functions play huge roles in the success of any angler, whether tournament fishing or just out having some fun. Unlike other sports, which only require a good pair of tennis shoes or a set of clubs and some talent to be successful, fishing not only requires knowledge of fish behavior and the ability to make proper presentations, it requires a smooth functioning array of equipment, all functioning together to be able to compete.
An area that has been a thorn in the side of folks for a long time has been interference between the trolling motor and the electronics. Due to innovations in the industry, this subject is worth another look. What causes interference and can we do something about it?
Interferences are electrical impulses that cause display screens on flashers or LCDs to either blossom or blank out while the trolling motor is engaged. Perhaps a black line will appear on your screen whenever you put your trolling motor to use, for example. Severity of interference might vary between trolling motor manufacturers, but there are several other sources of interference around the boat. You can't just assume that it's your trolling motor causing all the problems. Transducer positioning and wiring configurations can contribute to the problem as well.
Interference is most prevalent when the transducer is mounted on the trolling motor, and the electronics are on manual mode with the gain turned up and the trolling motor is on a slower speed. This scenario is one many anglers commonly face.
The first thing you want to do under these conditions is to turn the sensitivity down. You should have a button on your finder that shows from zero to 100 percent sensitivity. Turn the sensitivity to 75 percent. This move, in and of itself, will reduce some of the interference. times in the summer, when you have a lot of algae and plankton growth in a lake you can easily get away with 50 per cent sensitivity, so be careful not to go over 75.
Next, you must identify the source of the interference. With the sensitivity turned down, switch the trolling motor to the "high bi-pass" mode. If the interference disappears then the pulse modual speed control -- that knob on the side of the feet pedal -- is the culprit. If minor interference remains, there could be energy losses and shorts somewhere in the motor itself.
Be sure when you rig your boat that you don't run the transducer wire down the power cable or foot pedal for the trolling motor, because this will add to the problem. The transducer should run down the outside of the shaft. I know this doesn't always look the best, and you might be tempted to run it down inside your cable harness, but don't do it. By running the cable on the outside of the motor you will limit interference in a big way.
MotorGuide has come out with a great little item to help curb this type of interference. It's called an RF Choke. Simply wrap your electronics power cable around the choke five times. This device acts as an electronic filter; it's like a big clam shell that you close and place as close to your LCD as you can, and that's all there is to it. This item, along with the other things I've just mentioned, should eliminate your interference concerns. If you need or want more information, call me at 818-848- 6180, and I'll tell you how to get a hold of an RF Choke, along with an instruction sheet on how to mount it.
Grounding is an important issue for the trolling motor side of the equation. I've mentioned this in other columns, but it bears repeating here. If your trolling motor is not properly grounded, electrolysis, the movement or leak of electrical current could be a major source of interference and poor performance. Ground the motor to the negative side of the battery. I know this sounds simple, and it is, but you should see the numbers of people who don't get it. These simple methods mentioned here will solve your interference problems.
The fall should be an exciting time for fun fishing and for getting involved in tournaments, if that is something you want to do. Good luck and God Bless.
Reprinted with permission from Bass West Magazine
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