As with any sonar or imaging frequency, resolution (target separation) and range must be balanced against each other. The new MEGA Imaging frequencies have the highest available frequency of the common imaging frequencies (455 kHz, 800 kHz, 1200 kHz), which means that MEGA Imaging has the best resolution or target separation. At the same time, the MEGA Imaging frequencies have the shortest useful range of the Imaging frequencies. So, MEGA Imaging is a short range, high resolution technique. In our hands, the best MEGA Images are obtained using Side Imaging ranges of less than 100 ft.
This is an example of a MEGA Side Imaging view, collected on the Mississippi River in late fall. Here, we are transmitting a SI frequency range of 1150-1275 kHz, CHIRPing around the fundamental 1200 kHz MEGA Imaging frequency. In the HELIX G2N units, CHIRP is enabled across all of the sonar techniques. CHIRP is part of the reason that the above image is so crisp and clear. The image itself has a riprap shoreline along the left, with a tree extending out into the water, and several groups of fish suspended nearby.