Have 2 520c and when I turn on my bow unit with the trolling motor my panal unit will not show any returns any ideas??Thanks Matt

you might have a bad transducer...check to see if the line is pinched or cramped in any way. are you just getting that when you turn the trolling motor on...or is it just not showing any returns?

I believe the problem is from running two tranducers at the same time. Readings are based on timed returns. When your front transducer is on, the rear tranducer is also picking up its signal and results are scrambled. Problem is worse when two units of same brand are used. Sometimes you can run a different brand up front and it will work.

Using multiple transducers should not be a problem if they are not networked. Now, If they are networked then you will need the appropriate setup to handle dual transducers.

I run a X97 on the bow, a X135 and a 522c on the console. I can run them all at the same time without any problem.

I have a Eagle 480 and X-135 and must "Stop Chart" when I go to the front or I get lots of interference. Had no problems with the X-135 and Eagle 320 but do with 480.

Easy to "Stop Chart" on Lowrance/Eagle, be sure depth is current/active screen (not GPS), press Menu, cursor down to Stop Chart then press Enter. Uncheck (Enter, Exit) the box when ready to start it back. Stop Charts stops all signals from that transducer but leaves unit/GPS on so quick to get back going---faster than powering off.

Your going to get some interference running two units in deeper water. The returns will bounce of each other and then show some rain lines on the screens. I've noticed my HDS units aren't as bad as the older units, sensitivity running a little less. Stop Chart is the best way to stop int.. The new HDS have a HOT key to Stop Chart. Powers down the unit from the power key.

iwas told to change sensitivity on both units to different settings so they are not in sync, this works for me 135 lowrance on front 480 console try it and see

Try changing the ping rate. If they are the same it causes problems. I use 100 at the console and 55 on the front as you are usually going much slower up front and do not need the faster rate. That fixed my issues.