How many of you run two units? I currently have a bird 999 and like it for side imaging and love it for mapping. I like lowrance for traditional 2d sonar. (I am used to looking at it). Can I run both with rear mounted transducers and not get interference? I have to mount the bird external but would like to mount the lowrance thru hull. Thoughts? Drawbacks? Waste of time?
ANY two or more units operating on the same frequency will cross-talk when their sonar pulses overlap--it is a sure thing that close together.
Cross-talk will cause spikes on the displays and in some cases affect the depth readout.
You may can tolerate those, but some do not.
The Humminbird will be using 200 kHz for the depth readout no matter what frequency you select to view. I think you can select to just use 83 kHz with the Lowrance so it won't cross-talk with the HB.
A shoot-thru installation of a 2D sonar transducer is the best for high speed depth/2D sonar if the hull is suitable for that installation type.