OK, I posted the questions last night about interferance in the side scan (not the down scan) screen of the 797 when mounted on the bow troll motor. BASS CAT came back fast as ussual, thanks and what they recommended worked to a degree, but Motorguide recommended against it. That may cause a ground path through the trolling motor or the big motor that could cause damage to the internals. Turns out, the motorguide motors are designed to avoid interferance in the 83 and 200mhz range, which is where the fishfinders operate. The side scan operates in the 450 range, which motorguide does not address, hence the interferance. The interferance goes away at high bypass, because the digital speed control is out of the loop. Motorguide recommended making sure the boat is properly grounded, by running a jumper from the neg post of the trolling motor battery (the neg cable going to the trolling motor) and the cranking battery neg post. Then add a “RF choke” (thats the magnet thingy that is on some computer monitorss and battery chargers) to the power wire to the 797. My radio shop man said to put one on the positive AND neg wire going to the 797. They need to be 5 wraps and can be had at radio shack. Another interesting thing that Motorguide told me, to make SURE that the plug is unplugged or the foot pedal switch is off when ever you charge the batteries, or if you have an onboard (batteries charged with the big motor. seems the high amp draw can damage the digital part of the motor. Will post the result of adding the RF Chokes. Milton 2004 cougar 225 opti
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