Cross Talk

Why does my screen show vertical lines on it/when I turn on my other sonar unit or when someone is fishing near my boat?
When 2 sonar units are sending sound at the same frequency you can get cross talk. Each transducer is sending (pinging) and receiving sound and sometimes will hear the other sonar and you will see vertical lines. Since the cone shape of the sound from a transducer gets larger as it goes deeper you get more overlap of cones in deep water. In shallow water you get less or no crosstalk.
The arrows are pointing to the vertical lines. The sensitivity is set high to demonstrate the cross talk.



Sometimes you get crosstalk and sometimes the screen is clear even though the depth hasn’t changed. The reason is the transducers each send sound at different times and sometimes the difference is enough so that they don’t hear each other. On a Lowrance you can change the ping speed in the sonar menu. Sometimes this helps the easy way is to turn off one unit. On a Lowrance you can select stop the chart on the LCX/LMS/HDS units which will eliminate the cross talk. Stopping the chart stops the transducer from pinging.

 On the HDS units you can connect them with an Ethernet cable and see the same transducer readings on both displays with no crosstalk. For example; you can use the transom transducer looking for fish and switch to the trolling motor transducer when you start fishing. Your partner can see a clear screen on the console while you watch the bow screen. The bad news is we you see a fish and park the boat on the fish he knows what you doing since he sees the fish on the console screen!

Another choice on the HDS models is you can select 83 kHz for one unit and 200 kHz for the other and eliminate the cross talk since the difference in frequency is enough to eliminate cross talk. This is a splitscreen of 200 on the left and 83 on the right from the same transducer showing no crosstalk.