What's the difference between single beam and dual beam on a fishfinder?

Question

I'm interested in getting a fish finder, but I have no clue what the difference between single beam and dual beam is...

Thanks!

Answer 1

A single beam transducer operates at just one frequency usually around 200 khz and has a cone angle of anywhere from 12 to 25 degrees generally. A dual beam transducer operates at two different frequencies one around 200 khz with a 12 to 25degree angle and another in the 50 to 100 khz range with a cone angle of about 60 degrees. The lower frequency beam is good for tracking downriggers while trolling with a large spread, but is prone to background noise interference.