Getting The Most From Your Ice Sonar

By Joel Nelson

From the day you get your first flasher, the ice-fishing universe is forever changed.  I was 10 years old, the year was 1989, and for 25 bucks I got my grandpa’s old Lowrance 2330 which he had since given up on “figuring out.”  It was fairly simple to operate, and even conceptually, didn’t seem a technological marvel for its time, but what it did for your fishing was borderline magical.  I screwed together some one-inch pine strips in the shape of a “T,” used electrical tape to secure the open-water transducer to the bottom of the wood and set about dropping that ‘ducer into as many ice-holes as I could hand-auger.  Not only could I use it to catch fish and track how they responded to my bait, I could use it to find active fish before I even wet a line.  At the time, it was considered somewhat odd; almost a novelty.  Now, ice-fishing electronics are a multi-million dollar category, and the thought of fishing without one seems pointless.

In those days, any electronic assistance was a benefit, so features and specs weren’t something people really studied.  It was simply too new.  Now, all manufacturers produce multiple products per lineup, all with individual niches, functions, and price-points.  My goal isn’t to help you select what unit is right for you, it’s to help you get the most from whatever electronics you have.  Something is always better than nothing in the ice-electronics market, so whatever you do, get into it at the market level you can afford.  The used market is a great place to purchase these, but more importantly for those looking to make their first investment, it’s a good place to sell them should the unit not be right for you.  I’ve sold many flashers over the years and typically lose very little money on them, making it the cheapest rent possible on one of the most important pieces of ice gear possible.  Purchase worry-free, at nearly any dollar amount, knowing that you can easily sell it if you no longer want it.

Let’s look under the hood of your favorite flasher.  Digital or mechanical, circular, or flat-screened and square, there are a number of items most flashers have in common.

Water Depth

Undoubtedly, there’s an on/off switch, frequently connected to a setting that adjusts the depth of the display you’re fishing.  This is important, as you always want to be using the depth display that barely contains the depth you’re fishing.  If you’re in 32 feet of water, you want to be using the 40-foot scale, not the 80 or beyond.  Some of the digital units will select this for you, but the overall goal is to see the most detail possible by using the closest representative scale that matters to you.

Setting Your Gain

Next, you’ll want to set your gain appropriately.  This is the other main adjustment on your flasher and is of critical importance as it determines how “open” the receiver in your transducer is to gathering return sonar signals.  Your goal here is to set the gain as low as possible while still seeing your jig as a clearly defined mark.  Turn it too high, and you’re receiving a fair amount of noise in the form of double signals, and are also making the marks on your graph abnormally large.  This hinders your ability to see what’s going on by covering up valuable real estate on your sonar screen.  Just like there’s no reason to wear sunglasses indoors, you’ll see more by not obscuring your underwater vision with unreasonably expanded targets.

Setting Cone Angle

Here’s where the details get trickier.  Does your sonar have multiple transducer cone angles?  If so, make use of them!  Typically, a narrower cone angle is paired with a wider one to cover a multitude of scenarios.  The wide cone angle casts a bigger sonar net to the bottom, often providing optimum results especially when searching for fish that could be off to the sides.  That said, narrower beams are preferred when fishing steep breaks, as any sonar reads the closest edge of bottom the sonar cone first encounters, thus obscuring the remainder of the underwater slope.   Another reason to use a narrow beam is with other sonar in close proximity, like a buddy in a fish house, as it’s best to remove “noise” by only receiving the signals your ice unit is producing.

Speaking of noise, when fishing with a friend, how is your interference rejection set?  Do you notice intermittent marks that show up, racing in a circular pattern, thus blocking your ability to see fish or your bait?  Work with nearby electronics users by adjusting one unit at a time, partnering to remove interference for everyone.  Make sure gain settings are as low as possible to reduce the effect of this problem.  In deep water with hard bottom, expect this to be something you’ll need to address as sonar bounces off hard objects quite well, and over large distances has the opportunity to bounce off other signals that are produced by itself or other units.

That wraps up most of the basic concepts of your average ice sonar, and will in time become part of a routine that’s simply habitual every time you step onto a sheet of ice.  While they may seem rudimentary in their practice, you’d be surprised how many ice veterans run with high gain settings, no interference rejection, or the improper depth scale reading.  No matter which set or brand of ice electronics you use, keeping a few basics in mind when you set them up will make for a more productive ice session on any trip.

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