Fish Finder Basics: Frequency Demystified

If you want to know more about why CHIRP is superior to standard sonar, or if you’re curious about the science behind fish finder tech, check out this article.
What We Consider When Selecting a GPS-Capable Fish Finder

GPS and Mapping
Satellite location tech does a lot more than let you know where you are on the water - though that’s nothing to sneeze at! With the right maps and charts, and with mapping, chart plotting, and way pointing software, GPS enables game-changing opportunities.
Not only can you scout and mark ideal spots to fish, you can note hazards like shallows or rocks, locate docks, and create contour maps that revolutionize how and where you fish.
GPS and mapping aren’t gimmicks - they’re tournament-winning tech that’s within reach of every budget. But especially at the high-end, the software is simply amazing, offering contour map sharing that can get you up to speed in new locations quickly or turn you on to the best spots in no time.
Target Separation

Target separation is simply a measure of how precise the fish finder’s sonar is at distinguishing individual fish from one another. Smaller numbers mean better performance.
Transducer Beam Angle
Often a selling point, this is not nearly as important as marketing leads you to believe.
All other things being equal:
Wider angles let you see a greater area below your transducer.
But, and this is a big but, the “specified cone” isn’t the actual area the fish finder reads. Instead, it’s shaped more like this:
Moreover, for a specified beam width, the structure of the bottom can greatly affect performance. And the greater that width, the more likely this problem is.
As a general rule, the shallower the water you fish, the wider the transducer beam angle you want. Too much will create problems, and if you fish in deeper water, you want a tighter, more focused beam angle.
Side Imaging Sonar

This is exactly what it sounds like. Some advanced fish finders offer specialized transducers that transmit and receive off the starboard and port sides of your boat. The result is a 2-D image of the water column to either side.
Some brands sport a range of as much as 800 feet in either direction!
Obviously, this can be incredibly useful for locating fish, and it’s an increasingly popular option. Be aware, however, that the depth of these side-facing transducers is limited. Side imaging sonar won’t be penetrating the water column very far, though it’s an awesome compliment to a traditional transducer.
Maximum Depth

You want a fish finder with good maximum depth, and you want to match this rating to your actual use. Especially if you fish deeper water, like the Great Lakes, or if you’re a saltwater angler, this is something to consider carefully.
Display Size and Resolution
Larger displays are easier to read and use, but of course, they cost more, too.
And bigger isn’t always better.
Resolution is a measure of how much detail a fish finder’s screen can provide, and a small screen with great resolution can be easier to read than a large screen with only average resolution.
Final Thoughts
Which GPS-equipped fish finder is best for your needs and budget is only something you can decide, but we’re confident that you’ll be happy with whichever Humminbird or Lowrance model you choose from our shortlist.
For the pros out there, the Humminbird Solix and Lowrance HDS Live are simply excellent, with the overall performance - especially the mapping software - of the Lowrance really impressing us.
For serious anglers, the Helix and Elite are very hard to beat, and unless you need networking to control your trolling motor and outboard, the Elite FS 9 is impossible to beat.
Finally, if you’re looking for a budget-priced, small fish finder, Garmin’s Striker 4 is impressive, offering GPS features that no competitor does.
As always, we’d love to hear from you if you have a question or comment. Please leave us a message below!














