Help Needed - Interference on graph

[catchafew]

I have a Lowrance X25C on my console and a 520C on the bow/tm. Both graphs are powered by the motor battery. I experience interference on the 520C when I run the engine but do not have any interference on the X25C. Why do I have interference on one graph but not the other when they are powered by the same source? Should I use a different power source or how do I eliminate the interference? Thanks in advance for your help.

[beenfishin?]

Now this may be a stupid question, but I have to ask, is the transducer for the 520c mounted on the TM and if so, are you running the engine with the TM down??

[guest01]

Is one graph on your cranking battery and the other on the trolling.

[Barnacle Bill]

There are a couple of things you can do.
1. Try powering it off the TM battery.
2. Go to your local Radio Shack and purchase 2 ferrite blocks. Put
one the positive power lead and one on the xducer cable. Both as close
to the unit as possible.
3 Run a new power wire using a twisted pair. I make my own by taking a
red and black wire and twist them using a cordless drill. The tighter the
twist the better. Be sure to start out with much longer wires than you
need because they will get shorter as you twist. This is probably your
best bet.