Any time 2 separate sonar beams are overlapping, there is a potential for "crosstalk" sonar to sonar interference...

Mounting the 2 xducers close together creates this potential..

That is not to say that there will definately be interference...but a possibility...

Sometimes sonar to sonar interference can be filtered out with unit settings...sometimes not...

If the plan is to only use 1 unit at a time ...there would no sonar to sonar interference possibility..

I still have my 480 close to my 1197SI (but I only keep it there in case the 1197 decides to die)...

Rickie