Helix SI Chart Speed Setting

[Bjxds]

I have been trying to get the best quality on SI, experimenting with chart speed and boat speed settings. Matching chart speed and boat speed for the most part 4- 6 chart speed and matching mph. Is that the optimum settings or will it work just as well at slower speeds, 2 chart/ mph.

also In shallow water 5 feet or less should the bottom depth range still be set at 3x the depth?

I am getting some reasonably good images of structure in deeper water 20 feet or more but shallow does not show as well. I have found some bluegill beds and stumps I 5-10 feet of water but struggled to see it on the SI.

[Wayne P.]

Chart Speed matching the GPS speed gives you speed to size ratio==more realistic images. If you want the images stretched some so they appear larger, you use a Chart Speed that is higher than the GPS speed. If want stuff smaller/compressed, you use a slower Chart Speed to GPS speed.

For water deeper than about 20', a SI Range that is three times the depth will give you coverage with detain===1/3 of each side would be the water column, and 2/3 of each side would be the bottom.
To cover more area to see general features you can use a longer SI range.

In shallow water you don't have much water column to work with so Range would be whatever you want to show stuff large enough to see details like fish. I use 50' SI Range most of the time in less than 20' unless I am looking for large stuff like pan fish beds, a group of beds is large stuff:



If I want to check for bass patrolling the beds, then I use 50':



Big stuff deep (creek channel):

[Bjxds]

OK, in the first two pics, is the only that you changed is SI range, or do you need to adjust depth range Sensitivity, contrast....?

[Wayne P.]

OK, in the first two pics, is the only that you changed is SI range, or do you need to adjust depth range Sensitivity, contrast....?

I adjust as needed, when needed, as often as needed. I just go by what the image looks like.
The first image is a Helix 12 MEGA SI unit and the second image is a 1198c SI Combo using 455 kHz. I would guess the settings are different, there is about 8 years difference in those.

[Bjxds]

That makes sense now Thanks

[Dale Hollow Nut]

Good stuff !

[Jetch114]

Wayne is spot on on adjusting as needed. I'll adjust my sensitivity and contrast throughout the day. Small changes can make a big difference on image quality.