Thread: Question For Jerry Blake/Darrel Morris & Others (Electronics)

Originally Posted by Jerry Blake

Hey Tom:

I just have the basic unit with remote antenna. I can't tell much difference in the definition between the two units but I don't use them the same way. They both have features I like that the other doesn't have. On the 797 I can use the Fish ID with the Fish ID sensitivity turned way down so I only get fish symbols and depth readings from larger fish and still see the actual sonar returns of the fish. On the Lowrance if I turn on the Fish ID it filters out all the sonar returns of the fish so I keep it turned off. I had an issue with the 797 - the deal with the grid line depths not being corrected with the Depth Offset, which may be fixed with lates software update. Since installed a shoot-through-the-hull transducer for my downward looking sonar it's not a problem because the transducer is much closer to the surface. Rather than using an "Angled Puck" transducer I used a regular puck transducer and have it epoxied in the hull where there's about a 15-degree angle, which keeps the transducer shooting out where my front poles are. In fact, when I move the boat towards my front slip-float rigs so they are closer to the boat I can see the split shot on the line and I've even seen fish come up and take the bait or just come up and look at it.

The only other problem with the 797 is that I can't get a detailed map for Greeson and Lowrance has a free download for the 27c.

How far off is the depth up front, or do you care?

Originally Posted by Cane Pole

How far off is the depth up front, or do you care?

When using the downward looking sonar on the TM it took over a foot of depth offset to get an accurate bottom reading. Using the shoot-through-the-hull transducer at a slight angle the bottom depth is accurate on level ground. However, if it's shooting down a drop-off it will of course show a bit deeper because the beam is hitting the bottom farther down the slope and not right under the boat. It's just the opposite when shooting up a slope. It's not a problem once I got used to it. In fact its somewhat useful because I can see where the drop-off is in relationship to the boat without having to move the boat right over it.

It's real handy having the transducer "view" covering a good part of the area I'm fishing. When I see fish coming on the screen I only have to move the boat a few feet to put the bait on my front poles (or my jig) right in front of them. It's fun targeting individual fish or small groupls of fish. The angle doesn't seem to significantly distort the depth readings of fish or my jig. I've checked it with a weight on a string marked at different depths. I think the left side of my "cone" is basically vertical and the center is angled somewhere between 10 and 15-degrees. I'm only using about 25% sensitivity so small jigs and the split shot on my slip-float rigs have to be pretty much centered in the "cone" to see them.