800 khz. vs. 455khz.

[LY34]

on a 998 what is the differance in the 800 and 455 for side imaging? which should i use? also what should i use for for DI and regular 2D. I thought i read somewhere that one is good in real shallow water while the other is for 5ft. or deeper water on the 800 vs. 455 thing? idk thanks for any help

[rnvinc]

Below are the HB depictions for the 455kHz SI sonar beam vs the 800kHz SI sonar beam...

The lower the frequency number, the deeper the sonar beam can be used..but with less detail
The higher the frequency number, the more detail the image will produce...

Now, deeper is a relative term...as there as several things in the sonar world that can affect the effectiveness of the sonar beam...

Water depth, water clarity/water borne particles, bottom composition...are things that can absorb the sonar beam...(deeper water is going to absorb more sonar than shallower water - giving a darker image.... a hard rock bottom is going to reflect sonar better than a soft mud bottom - giving a brighter image...etc...)

I find myself using the higher detail 800kHz SI beam most often except when water conditions just will not let me get enough brightness into the SI image with the highest "20 SI Sensitivity" setting of the 800kHz SI beam...



Rickie

[rnvinc]

Now the DI and 2d...

In the HB "DI from SI" (like your SI series Unit)..I don't use DI very often but when I do...I use the Wide setting on the DI to cover a wider area of bottom....

2d...I use the 83/200 blended setting to cover more bottom with the 83kHz sonar cone (the 83 is a 60° cone) "and" get the better detail of the 200kHz sonar cone (the 200 is a 20° cone)...

I use "Switchfire On" for water deeper than 10 ft...and adjust the Sensitivity to an acceptable clutter level...
I turn "Switchfire Off" for water shallower than 10 ft....and adjust the Sensitivity to an acceptable clutter level...

(Switchfire On will really make the brush "pop" out on the screen, but it also shows clutter very readily which can make the image hard to distinguish at times...)

Rickie

[wilbur]

Rickie I never knew there was a wide setting, how do you get to it in the menu?

[South65]

I have had this discussion many times on here. I fish water levels from 7-25 ft most of the time and the 800 works fine for me. Also I run the 200 only beam on 2d because generally if it shows up on the 200 it will show up on the di at 800. Also the setting you are looking for is when you double click the menu button and go to sonar settings I believe


2003 Xpress X17
MinnKota V2 Powerdrive
Humminbird 998c
Cumberland Crappie Racks
BnM PSTs

[Barnacle Bill]

Here are a few screenshots I did a while back

[South65]

That looks like 800 on the right to me bill. Or the sensitivity/contrast is adjusted way different between the 2


2003 Xpress X17
MinnKota V2 Powerdrive
Humminbird 998c
Cumberland Crappie Racks
BnM PSTs

[South65]

Could b the difference between units. I don't know. I could never get pics like that on do at 455 just dots and so forth


2003 Xpress X17
MinnKota V2 Powerdrive
Humminbird 998c
Cumberland Crappie Racks
BnM PSTs

[wilbur]

On Bills shots the 455 looks like its got more detail than the 800

[wilbur]

Here is some in 800