Topic: 898 Clear Up Readings

[Cacciatore]

I am new to the unit 898c SI, and I have been having trouble getting some good views on it with the DI, and 2D. To me when I am looking at my DI on the screen nothing seems to stand out. I am tried adjusting the sharpness and contrast but the only way to get the timber to stand out is to have the Sharpness on say Low or Med. Here are some screenshots I took last trip out.

[rnvinc]

Your 2nd image is actually very good (and typical) of the DI views in the HB SI units...

We have to remember that the HB SI unit does not have a dedicated "down pointing" piezo ...but instead the DI view is a computer generated blend of the data received in the 2 "side pointing" SI piezoes ...

The echo "targets" directly under the boat are in the weaker edges of the SI fan beams ...

Imagine holding 2 "side pointing" flashlights at 60° out to your sides and expecting the light to be shining on your shoes ... Ain't gonna happen in the "DI from SI" technology ...
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On another note ... 2d views benefit from a faster chart speed ... Whereas DI views benefit from a slower chart speed ..

This makes a conundrum in a split 2d/DI view because the "Chart Speed" setting is global ... Not allowing independent adjustment of the chart speed for each sonar type's need ...

Rickie

[Cacciatore]

So would it be a better idea to run SI w/ 2D-Switchfire when searching for fish?

[Cacciatore]

Also I was using the wide beam, but should I put it down to narrow for better quality?

[rnvinc]

The DI Width setting is merely telling the unit to display a certain percentage of the total echoes being received in the 2 "side pointing" SI piezoes ... Any of the 3 settings would not be of better quality than the other ...

For example the "Narrow" setting tells the unit to display only the echoes that are common in both the left and right SI beams = the overlap of the 2 SI beams under the boat ...

The "Medium" and "Wide" settings are simply wider ... Not better ...or worse ...

It is sometimes beneficial to use the DI and 2d separately ... Use 2d for vertical fishing (stationary) and DI for slow forward scanning ... This allows us to set the chart speed setting needed for each sonar technology ...Without settling for a chart speed not optimal for either technology in a split view 2d/DI ...

As a side note ... When using the DI in the HB SI units ...scanning off to the side of known structure a little will give a little better quality DI image of the structure... because this puts the structure closer to the stronger part of the "side pointing" SI piezo beam ...

Rickie

[Cacciatore]

Ty most of our fishing this time of the year is trolling. I appreciate the responses.