Following your thread with interest. I also have watched the Youtubes and read what I can online, however, I still can't seem to grasp how to use the down view. My unit is the Garmin Echomap Chirp 74dv.

 

your screen will always be moving to the left... you are basically sending a single sound wave to the bottom over and over and over. If the boat is moving forward.. say at idle headway speed, as the sound wave returns it draws and image on the screen akin to a vertical layer of a jigg saw puzzle.. move the screen a little and the next vertical layer of the jigsaw puzzle forms on the screen. As the screen moves far enough for you to see a lot of the jigsaw puzzle an image begins to form that is sometimes recognizable to us like the bottom dropping or rising or seeing a pipe on the bay floor.

If the boat is not moving all you are doing is reshooting one vertical column of the jigg saw puzzle. and because the screen moves it keeps replaying that same vertical column over and over unless a fish swimms underneath the boat and then he may appear as a solid white sline. if he swims the the beam he'll appear as an arc and that arc will move across the screen. Why an arc? because as the fish enters the sonar cone he is at first furthest from the transducer then in the middle of the cone he is at the closest distance to the boat by a couple of inches then he moves out toward the outer edge of the cone and again is furthest from the boat by a few inches.. So generally an arc. Unless you have fish ID on and then he'll show up like a little cartoon fishy. Baitfish or shrimp clusters will show up as grass 'masses' in the water as you pass over them.

Reefs or other hard bottoms will show up as hard brighter areas on the bottom compared to dark soft mud. It all has to do with the reflectance of the sound wave. A soft mud bottom returns a dark signature because it absorbs much of the sonar signal, where a hard bottom reflects much more of the signal so it is much brighter sometimes white.

Also, you have to have the right settings if you are trying to look at to large a depth while you are in shallow water then all you'll see if the top with a lot of interference. Just leave your depth range on auto and that will help so if you are in 10 ft of water you won't try to look at a 40ft depth reading. you want the full 10ft to fill the screen.

Adjust your sensitivity to get the best picture.. too much and it will give you too much feedback.. too little and it's too light too dark. somewhere in the middle is best and it might change over different bottom types. Most of the time the newer machines have auto settings for this as well and it's a good place to start.

Also.. in shallow water less than 6-8ft.. you probably won't see many fish on that DV screen. It's shooting a small cone right under your boat and any self respecting predator fish is going to leave that area pretty quick with the outboard running. If you are drifting you might occasionally sneak across the fish. In coastal waters I use it to look for baitfish and edges of bottom structure and / or drop offs or edges of drop offs or rises. That's about the best use you can get out of it in shallow waters.

Hope that helps.

 

your screen will always be moving to the left... you are basically sending a single sound wave to the bottom over and over and over. If the boat is moving forward.. say at idle headway speed, as the sound wave returns it draws and image on the screen akin to a vertical layer of a jigg saw puzzle.. move the screen a little and the next vertical layer of the jigsaw puzzle forms on the screen. As the screen moves far enough for you to see a lot of the jigsaw puzzle an image begins to form that is sometimes recognizable to us like the bottom dropping or rising or seeing a pipe on the bay floor.

If the boat is not moving all you are doing is reshooting one vertical column of the jigg saw puzzle. and because the screen moves it keeps replaying that same vertical column over and over unless a fish swimms underneath the boat and then he may appear as a solid white sline. if he swims the the beam he'll appear as an arc and that arc will move across the screen. Why an arc? because as the fish enters the sonar cone he is at first furthest from the transducer then in the middle of the cone he is at the closest distance to the boat by a couple of inches then he moves out toward the outer edge of the cone and again is furthest from the boat by a few inches.. So generally an arc. Unless you have fish ID on and then he'll show up like a little cartoon fishy. Baitfish or shrimp clusters will show up as grass 'masses' in the water as you pass over them.

Reefs or other hard bottoms will show up as hard brighter areas on the bottom compared to dark soft mud. It all has to do with the reflectance of the sound wave. A soft mud bottom returns a dark signature because it absorbs much of the sonar signal, where a hard bottom reflects much more of the signal so it is much brighter sometimes white.

Also, you have to have the right settings if you are trying to look at to large a depth while you are in shallow water then all you'll see if the top with a lot of interference. Just leave your depth range on auto and that will help so if you are in 10 ft of water you won't try to look at a 40ft depth reading. you want the full 10ft to fill the screen.

Adjust your sensitivity to get the best picture.. too much and it will give you too much feedback.. too little and it's too light too dark. somewhere in the middle is best and it might change over different bottom types. Most of the time the newer machines have auto settings for this as well and it's a good place to start.

Also.. in shallow water less than 6-8ft.. you probably won't see many fish on that DV screen. It's shooting a small cone right under your boat and any self respecting predator fish is going to leave that area pretty quick with the outboard running. If you are drifting you might occasionally sneak across the fish. In coastal waters I use it to look for baitfish and edges of bottom structure and / or drop offs or edges of drop offs or rises. That's about the best use you can get out of it in shallow waters.

Hope that helps.

Ohhhh Tobin :rotfl: This man will help anybody with anything

 

On the downview you are looking directly under the boat. Downview and sideview are primarily used to locate and identify bottom structure and not fish.

 

I wish TS would be selective and working on the flounder dvd.

I have a new side view garmin94 and yet to be on the water with it.

If you watch enough utubes. There are many for HB and some for L and darn few good ones for Garmin.

The trend I got from looking since I got a striker 4dv for the tm IS to set up a split screen with regular sonar on one side and DV on the other. If you look at some of the utubes this will give you a better idea of what you are looking at.

The other thing to look at is the difference is the size of the view using the different frequencies. The lower the number the bigger the size of the cone angle of view on the bottom.

Lot of bs on the utubes of people that want to see themselves on the screen that do not know s... Still the best idea if you go thru and search by different parameters because depending you can get a world of different info to view..