Where are the fish actually located with sonar?

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03-12-2016, 11:43 AM
tnsandlapper

Where are the fish actually located with sonar?

I just bought a Lowrance Hook 5x. An example, I am in 60' of water. Display shows large arch at 40'. Not moving. With a 20 degree angle the cone diameter at 40' is roughly 39'. Or in other words a radius length of 19.5' from my transducer in any direction. If my boat is anchored, pointing due north or 0 degrees, the right side at transducer is 90 degrees, stern is 180 degrees, and left side of boat at transducer is 270 degrees. My question is, what direction do I cast my lure or bait and how far do I cast it? Can you help me? :pray
03-12-2016, 02:08 PM
Kevin22

Impossible to know, standard sonar doesnt orientate like that. Side imaging and 360 scan is the only way to know exactly where the fish are
03-12-2016, 02:25 PM
tnsandlapper

Quote:

Originally Posted by Kevin22

Impossible to know, standard sonar doesnt orientate like that. Side imaging and 360 scan is the only way to know exactly where the fish are

I kind of figured that but I am a newby at this and have a lot to learn. Thanks for the comment.
03-13-2016, 09:48 PM
gabowman

When a dot (arch, line, whatever) first appears on your screen is the most accurate reading you'll get when crossing over something or when a fish swims under your boat. Everything else you see is just history.
03-14-2016, 08:26 AM
tnsandlapper

Quote:

Originally Posted by gabowman

When a dot (arch, line, whatever) first appears on your screen is the most accurate reading you'll get when crossing over something or when a fish swims under your boat. Everything else you see is just history.

Would that be directly under the transducer or would it be from anywhere in the circle of the 20 degree cone angle? Thanks for your comment.
03-14-2016, 09:54 AM
vic n

You probably won't have an arch. You are anchored, so a fish entering the sonar cone will appear as a thick line. You drop a jig or minnow into the cone and watch it on your screen until it is just above the line. Jig a few times and see if the line comes up and smacks the lure.
03-14-2016, 10:31 AM
tnsandlapper

Quote:

Originally Posted by vic n

You probably won't have an arch. You are anchored, so a fish entering the sonar cone will appear as a thick line. You drop a jig or minnow into the cone and watch it on your screen until it is just above the line. Jig a few times and see if the line comes up and smacks the lure.

Thanks. I will try that. Just bought the Lowrance Hook 5x and haven't spent much time using it yet.
03-14-2016, 11:30 AM
CatFan

Quote:

Originally Posted by tnsandlapper

Would that be directly under the transducer or would it be from anywhere in the circle of the 20 degree cone angle? Thanks for your comment.

If you are moving forward, the left edge of the arch is where the fish first sent enough signal back for the transducer to see the echo. That's going to be generally in front of the boat as long as the fish isn't moving toward you from the side.

It's important to understand how the "cone" works. The stated angle isn't like a solid cut-off, but it's the point where the sonar is about half as sensitive as it is in the middle. You still get signal out past the limits, it's just lower strength than it is at the edge or center of the "cone". Imagine shining a cheap flashlight straight down as you fly over the ground. There is a central section where there is more light than out at the edge, but there is still plenty of light to see outside that center section. Same way the sonar works.

The reduced power and sensitivity away from the center is the reason the ends of the arch are thinner than the center. The return was capture further away from the center of the transducer beam.
03-17-2016, 01:00 PM
tnsandlapper

Quote:

Originally Posted by CatFan

If you are moving forward, the left edge of the arch is where the fish first sent enough signal back for the transducer to see the echo. That's going to be generally in front of the boat as long as the fish isn't moving toward you from the side.

It's important to understand how the "cone" works. The stated angle isn't like a solid cut-off, but it's the point where the sonar is about half as sensitive as it is in the middle. You still get signal out past the limits, it's just lower strength than it is at the edge or center of the "cone". Imagine shining a cheap flashlight straight down as you fly over the ground. There is a central section where there is more light than out at the edge, but there is still plenty of light to see outside that center section. Same way the sonar works.

The reduced power and sensitivity away from the center is the reason the ends of the arch are thinner than the center. The return was capture further away from the center of the transducer beam.

That's interesting. I just need to spend more time on the water using the Hook 5x. Thanks for your comment.
03-17-2016, 02:44 PM
vic n

Quote:

Originally Posted by tnsandlapper

I just bought a Lowrance Hook 5x. An example, I am in 60' of water. Display shows large arch at 40'. Not moving. With a 20 degree angle the cone diameter at 40' is roughly 39'. Or in other words a radius length of 19.5' from my transducer in any direction. If my boat is anchored, pointing due north or 0 degrees, the right side at transducer is 90 degrees, stern is 180 degrees, and left side of boat at transducer is 270 degrees. My question is, what direction do I cast my lure or bait and how far do I cast it? Can you help me? :pray

So the short answer to your question is: we don't know which direction to cast. However, if you pull up anchor and start moving with your trolling motor, the area you are concerned with is from 90° to 180°. Here is a link to show you what fish (and a jig) look like when you are sitting still. The thick red lines are the fish, and the thin angled lines are the jig falling and rising
03-20-2016, 01:29 PM
tnsandlapper

Quote:

Originally Posted by vic n

So the short answer to your question is: we don't know which direction to cast. However, if you pull up anchor and start moving with your trolling motor, the area you are concerned with is from 90° to 180°. Here is a link to show you what fish (and a jig) look like when you are sitting still. The thick red lines are the fish, and the thin angled lines are the jig falling and rising

Good pics. Thank you.
03-20-2016, 10:09 PM
fishinhunter

Here's a video that might shed some light on how your sonar shows you data:

https://www.youtube.com/watch?v=R4T0Tuv6RvY
03-21-2016, 07:35 AM
tnsandlapper

Quote:

Originally Posted by fishinhunter

Here's a video that might shed some light on how your sonar shows you data:

https://www.youtube.com/watch?v=R4T0Tuv6RvY

Thank you. Those were interesting videos.