So I have the unit that is in the title. I have been using it for a couple of seasons but am still pretty rusty with it. I was fishing the other day and I decided I needed help. my unit is in the back as I have a tiller steer rig. as I was going along I spotted a brush pile in about 12 feet of water. I throw out my marker to come back and fish it. as a ease back over the marker I cannot find the bush pile! I scanned the area for a while and never spotted it or felt it with my vertical rig. this happned severl times throughout the day. am I miss reading my unit or am I missing ith my markers? is th unit lying? lol how much area is covered by the unit? how should I have the unit set up? I need help!