Electronics - Imaging Frequencies

One of the biggest advancements in imaging sonar was Humminbird’s MEGA Imaging breakthrough. It took sonar into the megahertz range and provided the crispest, clearest, and most detailed images out there. It’s easy to assume that MEGA is better 100 percent of the time. We can’t forget about imaging frequencies in the 800 khz or 400 khz ranges. I’ll go over the basics of when I use each frequency as they all have times that they shine.

MEGA

90 percent of my Side Imaging is in less than 30 feet of water and within 100 feet of each side of the boat. MEGA always gets the call in this situation, I’m getting the most detailed view of the structure with it. I also can see fish the best with mega so it is helpful to know when they are around. If I want to look at structure with down imaging I also like how clear MEGA shows it.

800 khz range

This really shines when Side Imaging out deeper (see image in 50 feet). Often times MEGA returns aren’t very strong when you get out deep or far from the boat. So in order to see some detail you have to switch to 800 khz or even 400 khz in these situations. You won’t see the same detail of a MEGA image but you might miss everything entirely if you don’t drop down in frequency as the bottom will just appear really dark.

400 khz range

If you want to look a long way from the boat this is the frequency to use. Honestly I don’t do a ton of this because I’m often looking in a narrow area on the water bodies I fish. I do prefer to use 400 khz if I am looking at fish on down imaging. They will be bigger stronger returns and it is a great way to confirm what your standard 2D sonar is showing.