How to Read a Vexilar

by Heather Finch
Not all fish are this easy to find, unless you have a Vexilar.

Not all fish are this easy to find, unless you have a Vexilar.

For the serious fisher, Vexilar has been a household name since 1960, when it came out with its first product, the Deptherm. While the Deptherm was only able to measure the depth and temperature of the water, advancements in Vexilar products now allow fishers to determine where fish are lurking. Though the Vexilar products only show flashing colors, with a little practice you can break the code to interpret the information you need to know.

Identify the zero signal. There is a 0 on the top of the display with a broad red bar. Consider this the surface of the water.

Use the Range knob. The Range knob can be adjusted to show the best range of depth for the body of water you are on. The range X1 is best for water 0 to 20 feet deep; X2 for 0 to 40 feet; X3 for 0 to 60 feet; X4 for 0 to 80 feet; and X10 for 0 to 200 feet. To correctly read the depth, you will have to multiply the numbers on the circle by the Range value. For example, if a green flash shows up on the 5 mark while you are at a X3 range, you will multiply 5 by 3 to get 15 feet.

Find the bottom. There should be a second red band, the same size or larger than the zero signal. If you do not have a second red band, adjust the Range knob until you find one. The leading edge (the edge with the lowest value as determined by the numbers on the circle) is your depth.

Find a fish. Red flashes are the strongest signals and the most likely to be fish. Orange flashes are medium signals, and green flashes are the weakest signals. If you are stationary, a signal may start out green, turn orange and then red. This is very likely to be a fish moving towards the bait.

Use the zoom display. Switching the unit to AZ, or "Auto Zoom," mode with give a close up view of the bottom six feet of the water on the left-hand side of the display. The right side will show the entire depth of the water at twice the range setting. For example, if you have the Range set to 4x, the right side of the display must be multiplied by eight to find the right depths.

Items you will need

  • Vexilar FL-8, FL-12, FL-18 or FL-20


  • Remember to adjust the gain if the display is unclear or full of static.

About the Author

Heather Finch has been a freelance writer since the turn of the 21st century. Her official career began during her freshman year of college writing editorials about anything from manners to politics. Writings by Finch have appeared in the Western Herald, the Sturgis Journal and She has a bachelor's degree in creative writing and environmental studies.