# Newbie questions



## Tom 513 (Nov 26, 2012)

I bought my 1st boat last fall, a 14ft fiberglass tri haul outfitted with a 9.5hp Evinrude, 2- 40# trollers and a Eagle Fishmark 480 fish finder, wanting to find structure when fishing I am a little confused about how to read the screen and wondered if someone could advise me? my question and it may be a dumb one is- that the screen always is in motion from left to right, so how do u determine where it is looking? example it may show a downed tree, but could it be in any direction? seeing it looks like the transducer pans in a circular fashion? also I am getting the itch to possably upgrade to a newer model, are there any models that are user friendly and more accurate? thanks


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## rickerd (Jul 16, 2008)

your 480 is plenty accurate. I am still using my Lmx 480on Erie and it tells me the same information it always has. Now don't get me wrong, I know a DI will show much better information, easier to read, but I am saving for a larger screen SI unit in the fall. 

To answer your question, the sonar is taking a reading in a cone shape which gets larger the deeper you are. It sends those signals back and your unit shows the bottom at the highest point of data that is sent back. So in 40 fow, your sonar circle on the bottom is about 20 feet in diameter. If it reads 40 feet on a crown and 48 for the rest of the circle, it still tells you it is 40 feet deep. Think of it as a flashlight pointing down in the water. The light gets less intense the further away you shine it. Sonar is the same, the signal is accurate but is limited by the technology to show it in 2D on a screen. You can still go online and get the manual for your unit. There are good suggestions on how to read it there. Also do a search on internet for reading sonar and you can find plenty of screen shots and opinions on what you are seeing.

best,
Rickerd


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## Tom 513 (Nov 26, 2012)

Thanks for the feed back, I am still somewhat confused, but will do a search on the web as you mentioned.


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## crappiedude (Mar 12, 2006)

Tom
Here's a screen shot using SI/DI & 2d sonar. (Low HDS, Gen 1) 


If you look at the picks all 3 views show the same structure, they just show it differently. I agree with rickerd, don't sell that 2d sonar unit short, it's a good unit. On a 2d unit, I view the signal coming off a transducer like an upside down ice cream cone. The circle of coverage gets larger the deeper the water gets. As far as finding the cover in the cone it's really pretty easy. The right side of your sonar screen is the leading edge and most recent info. When you pass over some cover drop a marker buoy. I mean as soon as the cover stops showing on the screen drop it. You have to pay attention to the direction you are traveling, the cover will the be located behind that buoy. I then use jigs to probe the cover. With a little practice its fairly simple to do.
As far as where the cover is located in the cone. Different units have different degrees of coverage but the coverage area is really not that big. In 10 - 15 fow you may be looking at an area 3' to 8' in diameter. After dropping the buoy, the cover will be easy to locate. When I 1st started using sonar units, I used heavy jigs to located the cover like 1/4 oz. Once I located the cover in relation to the buoy, I would then switch to a lighter lure/jig to actually fish the cover. I hope this all makes sense. 
On thing I would want is a GPS unit. I used to use a cheap little hand held unit (garmin etrex) to mark my spots so the would be easy to find.
Of course if you have the funds I highly recommend buy the biggest unit out there with all the goodies you can get but if funds are more limited you can do just as good using a simple 2d unit with a hand held GPS. I know we fish the same waters and I did this for years.
I hope this helps.


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## Tom 513 (Nov 26, 2012)

Yes that helps a bunch Dude, I realize the upside down cone effect, and now that you mention the actual size of the cone I now know thats what direction ist actually scanning isnt all that important, its a horseshoe and hangernade kinda thing, lol I like the idea of dropping a bouy, then recording the longitude and latitude of the exact spot. I own a Garmin GPS and have been thinking about trying to use it to map structure areas, but that would be pushing my tech side more than I may be able to handle, although once perfected that info could yield some good fishing especially usefull this time of year when its a hunting game. 
I clearly understand 2 of the photos you posted, but the one on the left has me scratching my head! I will work with the equipment I have, I do have the manual but havent tinkered with the unit too much. I will be headed for the deep channels first this weekend and some older favorite spots. Thanks guys


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## crappiedude (Mar 12, 2006)

Tom 513 said:


> I clearly understand 2 of the photos you posted, but *the one on the left has me scratching my head*! I will work with the equipment I have, I do have the manual but havent tinkered with the unit too much. I will be headed for the deep channels first this weekend and some older favorite spots. Thanks guys


The pic to the left is side scan (SI). "0" is where the boat is. The darks stuff to either side of "0" is the water. The 60 is the distance it's showing to either side of the boat. 2d has a signal like the upside down ice cream cone. SI shoots a signal like a fan or an upside down turkey tail. With SI (side imaging) you are looking not only down but also to either side of the boat. If you look in about the middle of the SI pic you can also see the same tree that is showing in DI & 2d sonar. You can also see some additional standing timber on the left side on the SI photo, the lines just above the speed. SI helps locating cover to the sides of the boat.


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