If you own a Humminbird depth finder there are settings that allow you to change the kHz setting for your unit. So you may think does it really matter if I change these? I’m not going to get into the technical aspects of the inter workings of the setting I’m only going to show you three photos of why it matters when you are looking for fish. One thing is that these shots are from recordings taken with my Humminbird Onix 10 Touch SI and Humminbirds AutoChart Pro software. One thing to note is that the water depth under the boat is about 8 feet deep.
Here is a traditional shot of a tree and an old boat. The boat is to the extreme left and the tree is in the center of the shot. As you can see from the dark red colors this means it is a hard solid object. The setting is set to 200 kHz. From this shot you really can’t tell what the object is. If you can see at the very top of tall three shots this is very heavy current from water being released from the spillways at Pickwick Dam. They were actually spilling about 90,000 cfs. There are a few small fish that can be seen in this shot.
Here in the next shot I have the unit set to 455 kHz. With this setting the beam is set to wide and you can see farther out from what it straight under the boat. Again you can see the turbulence created from the current. Now you can see rocks and boulders laying on the bottom and a better view of the fish. The fish as you can tell are suspended and not on the bottom. There are a few very near the bottom and I think these are drum as I did catch a couple of them on a hair jig. The tree and the boat you can barely see them but you can make them out.
Now in the final shot I set the unit to 800 kHz for the down image settings. See how much clearer the old boat and the tree under the boat. Since the 800 kHz beam is much narrower you are able to see much more detail not only can you see the tree but the limbs on the tree. So all three settings have their place while you are fishing. To get the most out of your unit you have to play with the settings on your unit whether its an Onix or a core unit such as an old 597.
I hope this explains a little more about your unit and the settings and what it is capable of doing for you. I’ll post a few more shots as I find the time to get out on the water.