running both hummin bird and lowrance sonars

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?
C.J.

I have a HB and a Garmin mounted on rear side by side,..no problemo..

I have a HB 998 SI on front and HB Helix 7 on dash. Love both.

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.

Timely topic. I am running the Lowrance Elite 7 Chirp and wanting to add the Hbird Helix 7 Si. Both transom mount. Hoping for no issues.

I run the Lowrance 12 touch and the 1199C. Transducers are about 12" apart and do not get interference. I use the 1199 for 360, side scan and link system. The 12Touch for mapping, 2d and down scan. Doing it that way for 2 years at least.