Hummingbird question

[DublinCrappie]

Hello everyone, Im new to the site but have been hanging around sometime. My question is about the Hummingbird 787c2i. The unit works great, but I can not get it to show a fish arch when I turn the fish ID off. I have tried changing every setting on the unit. Any ideas are welcome. Thanks

[rnvinc]

Here is a good tutorial on how sonar works and why fish arch...
Sonar Tutorial | Lowrance

The 2d sonar has a cone shape beam...

The point where the fish first "enters" the cone shape is slightly farther away (from the xducer) than the point where the fish is in the "center" of the cone... This distance difference is what plots the first half of the fish arch....

Then, the point where the fish "exits" the cone shape is farther away (from the xducer) than the point where the fish was in the "center" of the cone shape... This distance difference is what plots the last half of the fish arch...

Not only does the fish have to pass "thru" the cone shape beam... The fish also has to pass thru the beam on a horizontal line so that the first and last "tips" of the fish are farther away (from the xducer) than the "center" of the fish...

Rickie

[Humminbird_Greg]

DublinCrappie,
First thing I would do is make sure that you have the latest software in your 787c2i unit. Currently that would be version 5.420. If you are not running the current software than update your unit (don’t forget to reset to factory defaults first) and try it again.

- What speeds is the boat moving at when you try and see these arches? There has to be movement between the fish and the transducer (boat) for the arch to form.

- Where is the transducer mounted?

- What water depths are you trying this at?

- What sonar beam(s) are you suing: 200kHz only, 83kHz only or 200/83kHz?

Post a Screen Snapshot of what you are seeing and also what menu settings you are using.

[rnvinc]

Here is a good tutorial on how sonar works and why fish arch...
Sonar Tutorial | Lowrance

The 2d sonar has a cone shape beam...

The point where the fish first "enters" the cone shape is slightly farther away (from the xducer) than the point where the fish is in the "center" of the cone... This distance difference is what plots the first half of the fish arch....

Then, the point where the fish "exits" the cone shape is farther away (from the xducer) than the point where the fish was in the "center" of the cone shape... This distance difference is what plots the last half of the fish arch...

Not only does the fish have to pass "thru" the cone shape beam... The fish also has to pass thru the beam on a horizontal line so that the u]first and last[/u] "tips" of the fish are farther away (from the xducer) than the "center" of the fish...

Rickie

I have to correct my statement noted in blue above....it should read...

Not only does the fish have to pass "thru" the cone shape beam... The fish also has to pass thru the beam on a horizontal line so that the first and last points that the fish is in the cone shaped beam are farther away (from the xducer) than when that fish is in the "center" of the cone shaped beam....

Rickie

[DublinCrappie]

Thanks for the information.
1.The transducer is mounted on the trolling motor. Have tried it level and at an slight angle.
2. 5-35 FT
3.200/83kHz
4. Boat speed .05 to 1.4

[rnvinc]

Here's an interesting experiment....

Turn the unit on.....
Tie a "fish sized object" to a line...(coffee cup or similar size)
Lower this object into the water outside of the sonar cone shape...
Pass the "fish sized object" thru the sonar cone shape....
Watch the unit screen to see if it paints an arch...
Test different settings and depths (of the object)...

Rickie

[Humminbird_Greg]

Dublin,
Try making a screen snapshot of what you are seeing.

You may also want to try:
- slowing the Chart Speed menu setting down. The arch may be there but is getting stretched out over a wider area.
- setting the SwitchFire menu to the Max Mode setting.
- the various Sonar Color menus settings as the arch may be there but you may not be able to see it due to the lighting conditions and the colors used for the weaker (outside edge) sonar returns.

[bdorman]

Maybe there's no fish there?

[kosmo]

Hello everyone, Im new to the site but have been hanging around sometime. My question is about the Hummingbird 787c2i. The unit works great, but I can not get it to show a fish arch when I turn the fish ID off. I have tried changing every setting on the unit. Any ideas are welcome. Thanks

try lowering a jig or waited line with your choice ofbait.while your boat is not moving raise and lower the line. if the sonar does not track the movement then i would think that there is something wrong with sonar or transducer. try the 200/83 combo first

[Lowrancehd]

Reach behind the unit and press the release button from the mount discarding the unit and replace with a Lowrance Hds