Topic: Transducer options.

[theflatlander]

I have been trying to learn as much as I can about my graph (858C HD DI) and have watched all the Doug Vahrenberg videos and it has help a bunch. When he is talking about Switchfire mode I have only noticed him mention 200, 83, or 200/83. My depth finder automatically go's to 200/455 DI. Do I still have the availability of using the 200/83 DI or wont my unit work right with the transducer I am using?

I am really stumped on the whole transducer option thing and I dont know what options I should be using for switch fire or DI mode. Do I have any options besides DI 200/455 with my unit? Does it automatically change the best transducer option when what ever mode I decide to use or Should I be going to my options and changing my transducer settings?

My graph gives the following transducer options. DI 200/455, DI 200/83, Dual 50/200, Dual Beam, Quad beam, DI 200/50. I dont know what options work, what dont, and what will work the best for me. I fish inland lakes very seldom will I ever see anything 150ft deep and most of my fishing takes place under 30ft deep of water.

Any help appreciated. Thanks

[4d-rock]

As far as i remember from my research, The Down imaging units only have 200/455 for 2d frequencies on it's transducer.

The regular sonar and Si units have 83/200 for 2d frequencies.

[theflatlander]

thanks 4D. I just dont understand why I would have all the other options but only one will work.

[ITGEEK]

Those other options are for different types of
transducers, and if you wanted to use
an aftermarket transducer, such as Airmar.

With your current transducer, probably only
one transducer type can be selected.

[Humminbird_Greg]

Those are menu selections if you purchase and connect up a different transducer.

With the stock transducer that came with your 858c HD DI unit (XNT-9-DI-T) you should be using the DI 200/455 setting.

There is an optional Trolling Motor mount XTM-9-WIDE-DI-20-T transducer that uses the same DI frequencies (455/800kHz) but uses a different set of 2D sonar frequencies (200/83kHz).  You would use the DI 200/83 setting for this transducer.

You can use a deep water 50/200kHz Dual Beam transducer with your 858c DI unit but would only have 2D sonar (No DI sonar).  You would use the Dual 50/200 setting for this transducer.

You can also opt to connect a standard 200/83kHz DualBeam transducer to your transducer with your 858c DI unit but would only have 2D sonar (No DI sonar).  You would use the Dual Beam setting for this transducer.

You can opt for a QuadraBeam transducer to be connected to your unit.  This is a 2D transducer that has two extra sonar beams that cover a much wider area than most 2D sonar and DI units do. You would use the Quad Beam menu setting for this transducer.

I’m not sure about the DI 200/50 setting as we currently do not make a DI transducer that is capable of these frequencies.  Maybe this is in case someone uses a standard XNT-9-DI-T transducer along with a 50/200kHx Dual Beam 2D transducer (and the AS-Si-DB-Y cable).

[theflatlander]

thanks for all the info guys. what degree beam is the 200 and which is the 455?

[ITGEEK]

This is from Humminbird's website:
Down Imaging® w/ DualBeam PLUS™
 w/SwitchFire™
 200 kHz / 25° @ -10db
 455 kHz / 16° @ -10db

[Humminbird_Greg]

I figure you are more interested in just how much water coverage that translates into, so here are the numbers for our standard XNT-DI-T transducer:
2D (conventional) sonar:
16 degrees at 455kHz,  area covered = 0.28 X water depth
25 degrees at 200kHz,  area covered = 0.44 X water depth

DI sonar:
45 degrees at 800kHz,  area covered = 0.83 X water depth
75 degrees at 455kHz,  area covered = 1.53 X water depth

[theflatlander]

thanks again guys. I just got back from a awesome fish trip on lake of the woods for a week. I dont feel like I have something set right on my unit or that I am just expecting to much from the DI setting. What should I be seeing compared 2d to DI? should i be seeing bottom structure way more defined than on the standard 2D screen? I cant help but not thinking I dont have something set right with my unit or my transducer isnt quite the right angle because of right now I am not seeing the big advantage using the 2D compared to DI.

IF someone cares to or could explain to me what is the huge advantages of DI over 2D? how do I know if I have my transducer at the right horizontal and vertical angle in contrast to my boat?

[Humminbird_Greg]

“should i be seeing bottom structure way more defined than on the standard 2D screen?”
Yes you should.

The advantage would be to be able to more clearly see what is under the transducer.  You should be able to see a tree as a tree and not some ‘blob’ of color on the 2D sonar screen.

About the only way I know of telling if your transducer is set right is by looking at the shape of the arches that suspended fish make.  The leading and trailing parts of the arch should be mirror images of each other.  If your transducer is tilted too far down or up (when viewed from the side) one will be longer than the other.  As for side-t—side tilt.  You could take a level gauge with you on the water and take a reading and than compare it to what you see while on the boat trailer and the angle that the transducer shows.  However, your transducer would have to be very misoriented to not be able to get a clearer image in the DI sonar versus the 2D sonar.

Post some screen snapshots of what you are seeing along with what menu settings and boat speed you were using.

[theflatlander]

thanks again greg. I will do this the next time I go out fishing.