Questions And Answers About Depth

Some answers to questions about Fish - Depth Finders.

What is a Fish Finder?

A fish / depth Finder is a SONAR (SOund NAvigation RAnging). Sound moves thru water at about 5000 feet per second. Your fish finder measures the amount of time it takes for the sound pulse it sends out to travel to the bottom and back. In simple terms your fish finder acts first like a speaker (sending the sound out) and then switches over to a microphone (picking the sound up). Now anything that gets in the path, sends back an echo which can be interpreted by your fish finders electronics as bottom, fish, rocks, logs. Remember the unit does not know what an object is it just returns an echo.

Why are pixels so important?

PIXEL (Picture Element). A dot Color or Grayscale. The greater number of pixels per inch the greater resolution. Pixels are arranged in columns and rows and the more pixels in the column, the greater the detail. The greater the detail, then a small change in the bottom contour allows the structure to jump into your sight on your fish finder display, therefore giving you better information.

What do all those arches mean?

Those boomerang shaped arches your watching are all related to the transducer cone. Let's say your transducer is sending out a signal shaped in a 60 degree cone and a fish swims thru at 20 feet, your fish finder measures the distance and puts it out on your display. When the fish comes into the cone, its roughly 20' away, when its directly under the transducer about 19' and when it leaves the cone its roughly 20' away again. This causes the arch effect. Lets say the fish gets startled, changes direction, changes depth then you won't get a perfect arch.

What is RMS, peak to peak and why is it so special?

RMS (Root Mean Square) and Peak to Peak are used to describe the output power on your transmitter. This is why fish travel around in schools :-) Now, more power is not always better, its a combination of power and receiver capability.

What's the difference between wide and narrow cones?

A transducer with a wide cone (50 khz) scans more water and tends to lump things together whether it be fish, stumps, rocks, etc. A narrow cone (200 khz) can detect small details and focuses on structures at a greater depth. The disadvantage here is that it scans a smaller amount of water.

How do I tell what's on the screen?

This all comes down to density. Anything denser than water will give you an echo. So although you don't see the fish it doesn't mean they are not there. This is what makes you a better fisherperson. Weeds, brush, trees, rocks are great places to find fish. You just have to develop your skill to recognize them and then you can land your big one.

What's better LCD or Flashers?

Although it is easier to read a LCD that gently scrolls across the screen, they are both basically the same. Think about those vertical columns of pixels we talked about before. Thats the same thing your getting in a flasher without the LCD taking a few soundings, doing some averaging and some filtering before you get to see it. Its all about "real" time, by the time you get to see it, it could be gone.

Questions & Answers About Depth - Fish Finders.

Some answers to questions about Fish - Depth Finders.

Depth / Fish Finders