That is correct. I did some looking online about setting the gain. I found the following on the Vexilar website that talks about the importance of making the jig a green signal:

"It is critical to set your gain level so your lure or bait is displayed as a green signal. If the gain is set too high, the ultra powerful receivers of the Vexilar unit will make everything suspended below you look like one big flashing mass of colored lights. When set properly, you clearly know where your lure is, and where it is in relation to all the other targets you also see on your display. The ideal scenario is that when you drop your lure down to a fish target, you see the fish signal move upward to meet your falling lure"

http://www.vexilar.com/blog/2014/08/28/improve-your-ice-fishing-by-50