Hummingbird Fish Finders - About the HD Sonar
Some of the Hummingbird Fish Finders
come with HD Side Imaging or Down Imaging technology. These are outstanding units for finding fish and usually have also, very nice navigational capabilities. Anyway, in this report I'm going to speak about the HD sonar capabilities found in some of the best Humminbird units, like the Hummingbird Fish Finder 898c SI Combo.
Humminbird Fish Finders endowed with Side Imaging
provide a wide survey of water allowing you to see what's underwater on 240 feet on each side of the boat, on depths down to 150 ft. The Side Imaging sonar returns will show you detailed bottom topography and fish-attracting structure orientation. The images are all very clear, being similar to an aerial photo. Normally, the Side Imaging sonar frequency is set to 455 kHz, but the beams can also operate on 800 kHz. However, at 800 kHz, although you will receive the sharpest images, the side-to-side scanned surface and the depth are limited.
Not all Humminbird units have both Down Imaging. However, there are a couple of very reliable units that feature only Down Imaging, like the Hummingbird Fish Finder 597ci HD DI Combo. Find out more about the units of the Humminbird 500 series, here: http://hummingbirdfishfinderreviews.com/category/500-series/
Down Imaging sonar basically provides the same returns as the standard sonar, but with the same clarity as the Side Imaging. So, you will benefit from clear images, the same photo-like clarity of what's directly under the boat. DI allows you to distinguish exactly if the structure under your boat is a submerged tree with it's branches rising up, or if you're looking at a few fish. In standard SwitchFire imaging, you can easily mistake a tree's branches for fish.
Also, you can benefit from the HD Down Imaging in split-screen with the standard imaging for a better understanding of the bottom contour and the structures under the boat.