How to read your vexilar?

[Dragonfisherman]

I am hoping that someone can help me out, because I recently purchased a fl-8 and I would like to know how to read bottom transition on it. If someone could shine some light on this, that would be much appreciated.

[Ed Carlson]

You can find hard bottom while ice fishing with your flasher. Realistically, you will only be able to determine if the bottom is harder or softer than the area you have just checked. You'll need to have a number of holes drilled. Turn the flasher on to a deep range and set the gain up high. Now when you move from hole to hole, take notice of the strength of the multiple echoes.

There are two ways in which your sonar will show you changes in bottom hardness. One way is by a difference in the appearance of the bottom signal. As the bottom gets harder below, your sonar will show the bottom band getting wider/stronger. If you know the bottom is relatively flat, you can use this information and feel fairly confident in what your unit is telling you. However, if you're not sure how flat the bottom is, you can be mislead because a bottom with a steep slope will also show as a wider band than a flat bottom. The other, more reliable, method to use is to notice the changes in the second or even third echoes beyond the bottom.

An echo is created when the unit transmits a burst of sound and that sound is reflected back to the transducer. When this sound pulse reaches the transducer, it hears the sound, the unit calculates how long it took for the sound pulse to go down and back, and displays the result as bottom. But the actual sound doesn't stop there. It is reflected by the surface of the ice and back down toward the bottom. The sound is then reflected upward again. When it reaches the transducer this time it is much weaker. The sonar also notices that it took this sound pulse twice as long to get back to the transducer. The result is a second echo. This repeats over and over. The sonar unit will display as many echoes as it sees. At some point, the return echoes strength will be so weak that the unit will not display it.

To read these multiple echoes as a bottom hardness indicator it is important that your sonar be set up properly. A second echo is always twice as deep as the first echo, or bottom. Lets say the depth is 25 feet and your depth sounder is set to a 30 foot range. The second echo, at 50 feet, will not be displayed. However, if you manually change the range to 60 feet, the second echo will now be visible. To see a third echo, you will need to have the unit set to a 75 foot, or greater, range.

Now that you can see the echoes you are ready to determine the bottom hardness. A harder bottom will reflect sound much better than a softer bottom. The more echoes you see and the stronger/harder the bottom is. This will hold true as long as the depth stay similar. If it gets quite a bit shallower or deeper, you'll need to adjust the gain accordingly.

The gain, or sensitivity, control is your feelers. Turning it up is like applying more pressure with your hand on the ground to feel if the soil is soft or hard. Determining sonar readings is a lot like this, learning to see/feel the bottom.

Nothing to it once you tinker with it a bit. Don't let it intimidate you. If I can figure it out...anybody can.

[bturck]

I've been using Vexis for many years and understand them at least 90% of the time. However I found your explanation of the operation very good. It just made more sense of what i had been reading on mine for years. thanks for taking the time to put it all in words. good luck and hang on. Bill

[uffdapete]

I agree - very helpful information in terms a novice can understand!

[Dragonfisherman]

Thanks a lot Ed, You gave me all that I was hoping for and more. Now that is a response.

[mrwalleye_13]

i just learned a lot of stuff i didnt even care to learn.. thats awesome! I have also learned a ton from my aqua view. Reading the vexilar.. sometimes it says i am pretty much on bottom according to the vexi.. and u end up being a foot and a half off when u look at it with the camera. You really see botoom differntly then you think it would look. Definetly some useful info Ed. Theres so much i have learned off of just this site its amazing