Fish Finder/gps Questions

[GoTakeANap]

Hello everyone. I'm having a little trouble picking out a new fishfinder/gps for my bass boat. The model I currently have is a Humminbird 581I DI. Anyone have this model? I need something a little more advanced and in detail on underwater structure and something that tells me there are fish there a little better than other models. The brand I would to purchase are Humminbird or Lowrance. Thanks for the help.

[Lund Explorer]

I would suggest you stick with a Humminbird if that is what you are used to. I'll leave it up to someone who doesn't use a Lowrance to suggest the best models.

[IMPACT01]

7 series Humminbird with SI and DI. Great unit!

[Wayne P.]

The unit you have is a limited edition special sale model, BUT it has the highest display resolution in the industry for that size unit.

Color would be your best improvement for that type unit. More power would be an improvement also.

In the Humminbird 500 series, the 597ci HD DI Combo unit is the top of the line for what you have.

In the more advanced data sharing models (700, 800, 900, 1100 series), the 1158c DI Combo is the top dog in the DI models.

Your budget will determine how "advanced" you can go.

A Humminbird Side Imaging unit will give you more information, BUT the DI images they produce are not as sharp as the DI units produce. The SI units use software to create the DI image using the two SI crystals. The DI units have a dedicated DI crystal.

Every sonar unit made by any company will show you fish and bottom contours. You have to learn how to operate them and interpret what they show.

I know some that have the top of the line imaging systems by Lowrance or Humminbird and don't take the time to learn how to use that technology--they just use them to get the depth.

If you cannot find fish or structure with what you have, spending more for a more advanced unit won't do you any good.

If you cannot get your DI unit to give you images similar to this of a river channel with bridge supports and fish from a Humminbird DI unit ; PRACTICE-PRACTICE-PRACTICE

[GoTakeANap]

im thinking about going with the humminbird 858c DI combo. anyone know about this one? i can find fish on my current model finder but i want a better picture to show me what exactly is on the bottom. i can find trees, stumps and etc but having trouble finding that bite. gotta go to deeper water this time of year.

[GoTakeANap]

The unit you have is a limited edition special sale model, BUT it has the highest display resolution in the industry for that size unit.

Color would be your best improvement for that type unit. More power would be an improvement also.

In the Humminbird 500 series, the 597ci HD DI Combo unit is the top of the line for what you have.

In the more advanced data sharing models (700, 800, 900, 1100 series), the 1158c DI Combo is the top dog in the DI models.

Your budget will determine how "advanced" you can go.

A Humminbird Side Imaging unit will give you more information, BUT the DI images they produce are not as sharp as the DI units produce. The SI units use software to create the DI image using the two SI crystals. The DI units have a dedicated DI crystal.

Every sonar unit made by any company will show you fish and bottom contours. You have to learn how to operate them and interpret what they show.

I know some that have the top of the line imaging systems by Lowrance or Humminbird and don't take the time to learn how to use that technology--they just use them to get the depth.

If you cannot find fish or structure with what you have, spending more for a more advanced unit won't do you any good.

If you cannot get your DI unit to give you images similar to this of a river channel with bridge supports and fish from a Humminbird DI unit ; PRACTICE-PRACTICE-PRACTICE

so is the side imaging better on a di or si unit? also what does the more power do in a fish finder?

[IMPACT01]

You would want both optons.

Do you fish deep water?

The power of the unit describes the power of the transmitter. The more power the better and more accurate your returns will be. Have you tried to use your fish id in your current unit?

How high is your sensitivity set?

[GoTakeANap]

You would want both optons.

Do you fish deep water?

The power of the unit describes the power of the transmitter. The more power the better and more accurate your returns will be. Have you tried to use your fish id in your current unit?

How high is your sensitivity set?

i have at lake murray but not in this lake. santees avg depth is about 10ft besides the river channel is around 25 to 30 ft. not sure what my sensitivity is set on but i change it all the time. yes i use the fish id on my humminbird.

[IMPACT01]

Some things you need to know. If you have a 20 degree finder it will pick up half the depth you are in. So 10 ft deep you are coving 5 ft of the bottom.

If you turn up the sensativaty in shallow water you will get the best reading. If you turn it up in deep water it will tighten your cone but give you less reading but wil be more accurate. Less sensativaty less confinement or picture but not as good of. Return.

How is your fish I'd set.

[GoTakeANap]

idk if this one has 20 degree or not. i dont see it anywhere on the info. http://store.humminbird.com/products/478475/858c_DI_Combo

[IMPACT01]

the 858 should cover 100 percent of your depth. The only problem is you are going to wish you got the SI model.

Good luck man!

[slonezp]

so is the side imaging better on a di or si unit? also what does the more power do in a fish finder?

DI is standard on the SI unit. SI is not available on the DI unit

[Wayne P.]

Traditional Humminbird units use 200 kHz with a -10 db spec cone angle of 20 degrees and 83 kHz with a

-10 db spec cone angle of 60 degrees. The actual coverage is a lot more at weaker sound strengths.

The Imaging technology uses a sonar pulse that is very thin front to back and wide to the sides.

The Down Imaging units have 455 kHz and 800 kHz plus 455/200 kHz regular sonar

The DI 455 kHz spec coverage at -10 db is 75 degrees and the 800 kHz spec coverage at -10 db is 45 degrees

The cone angle of the 455 kHz is 16 degrees and the 200 kHz is 25 degrees for some of those models

The Side Imaging units in the Side Imaging function cover 180 degrees with the 455 kHz and about 60 degrees with the 800 kHz. They also have 83/200 kHz traditional sonar.

There are two 858 models--858c Combo and 858c DI Combo refer to the coverage for each frequency.

[GoTakeANap]

the 858 should cover 100 percent of your depth. The only problem is you are going to wish you got the SI model.

Good luck man!

why is that? whats the 2 big differences in those models?

[Wayne P.]

This is why. How much bottom coverage will you get with regular sonar or Down Imaging at this depth?

[Wayne P.]

Another example of Side Imaging, You can keep up with creek channel changes of direction and not wander all over tying to find it with 2D or DI.

[IMPACT01]

For those that don't know how the screen reads. The boat is in the middle top( blue thing that looks like a boat. The rest is a picture of a side image display. The middle number on the bottom isthe water depth of the boat.

So in 1.6 ft of water to the right he has picked up a change in structure/ depth.

With the DI unit in 1.6 ft of water you will pick up 0.8 ft of the bottom where he is picking up 10.0 ft wide.

So

A. He passed through the same area as you and picked up fish on the bank while you trolled through the area never finding the structure.

B. In deep water with bait you are looking for baitfish and with them you will find the big fish. So it is a lot of water covering, marking and fishing. So if you are in 25 feet of water with DI you get 20 to 25 ft of the bottom. With the SI option you go up to 40 to 50 ft. Not sure if my numbers are exact but the y are close. any way cover twice as much water pick up twice as many fish = twice the smile on my face!

[Wayne P.]

What the first image represents is I was checking the creek channel on the left side (darker area) because the main lake water temp was 89-89 degrees and there had been a heavy rain. I was looking for shad and bass that may have moved to the cooler water. In the middle of the right side there is a gray blob which is a school of shad next to a stump (bright white dot). At the top of the image and in the creek channel are bass (the white streaks). I caught two of the bass after taking the screen shot. If had been in the creek channel following it with regular sonar or Down Imaging, I would have scared the fish and not even known they were there. I duplicated that same senario several times in that area.

I was using the 50' range setting to have the needed bottom coverage for what I was doing and have it short enough to recognize fish. The unit can be set to display up to 360' on each side, but that makes stuff look a lot smaller on the display.

My point for posting the picture is the Side Imaging technology will allow you to see horizontally to display what is in the area even in shallow depths. The display is on my bow and the transducer is on the trolling motor.

The second image is with my console display and the transducer on the transom.

[GoTakeANap]

which model would you go with? Humminbird 898c SI or Humminbird 958C? i know which one i want but which one is better all around.

[Wayne P.]

which model would you go with? Humminbird 898c SI or Humminbird 958C? i know which one i want but which one is better all around.

Definately ---- 898c SI

The 958c is a dual frequency 83/200 kHz regular sonar unit and the 898c SI does the same and has Side Imaging and Down Imaging too.

[GoTakeANap]

Definately ---- 898c SI

The 958c is a dual frequency 83/200 kHz regular sonar unit and the 898c SI does the same and has Side Imaging and Down Imaging too.

thats the one i had selected. i ended up calling humminbird and talked to a sales rep about it. he answered all the questions i had. suppose to send me a video on how to use and identify fish. cant wait.

[Wayne P.]

Do a web search for Humminbird YouTube Humminbird TV

[GoTakeANap]

i ended up going with the humminbird 998c SI combo. ordered it today. cant wait. thanks for all the help guys. im sure ill end up asking more questions in the next few days when i try to figure this thing out.