settings for hbird 718/728

Greg,


Here's some FF 101. Why see arcs?

FF's have two modes. Fish ID and arcs. The problem
with Fish ID is this: If you have a school of macks under
you, your FF (with Fish ID on) will show the biggest
mack as a big fish on your monitor. Or if you have a whale
under you, again, your ff will show a big fish.

But the arcs will show you relative "real" sizes of fish.

Let's define arcs.

The sonar beam under the kayak is like a fanned out flashlite beam
aiming towards the bottom. On some paper draw the ocean
floor, the water's surface and you with a big halibut in your
yak with the flashlite beam pointing towards the bottom.

As a big fish enters the flashlite beam, it's entering the longest
part of the fanned out beam. So, your ff marks the fish, deeper than it is.
Since the sonar sound wave is traveling its furthest. Now, as the fish continues to swim, it is directly underneath your yak and thus, your ff (continuing to mark the fish) thinks the fish is closer since the sonar sound wave is traveling as shorter distance, its center. Now, your monitor will show an up swing in its representation of the fish. Then, as the fish continues and moves towards outer beam, your ff will see the fish as further down since, again, the sonar sound beam is traveling further.
This is why a FF shows a big fish as an arch.

If the ocean were perfectly still, and your yak was perfectly still, arcs would look like perfect arcs. Caveat: Don't be decieved by any FF's simulation. That's preprogrammed stuff that isn't reality.

Since everything is moving, the game is to see unperfect arcs and recognize them for what they are.

Now the next topic: Seeing arcs. I've been thinking for the best way to communicate this concept. Here goes an analogy.

Imagine you're looking for Big Eagles perched on trees with a digital camera. You're taking pictures, from 50yards, and then looking at the prints. You're trying to find the Eagles in and amongest the leaves and branches.

If your camera has an expensive, good lens, it will pick up all the detail you need see the eagle. But then, your printer, that prints the image, has
got to print that image with high pixelation (sp?). So you can see the diff
between the Eagle and the other stuff.

Even if the Eagle is perched all alone on a branch without leaves, you would think that it would be easy to see on print. Not if you camera's lens is poor or out of focus, and not if your printed picture has big pixels. What you will see is a branch that has leaves on it. Because you won't be able to make out the Eagle's outline.

That's how a good FF works. It has to have the power to pick up the details of the Big Fish and the high resolution Pixels to show the details of the Big Fish from its surroundings, like bait fish. When I say details of the Big Fish, I mean the arch.

I've found that a power rating (ability to pick up details) of 500RMS is a minimum. And screen pixelation (ability to show details) is 480x480 is a minimum. Otherwise, you won't be albe to tell the Eagle from the Leaves.
A color unit having these specs is more money than a B/W.

As a side note. It's true that a jig is denser than a fish, but FF will show a jig, a mack, and a big fish as a solid mark. So the game is to figure out whether you're looking at a big fish arch or a cluster of baitfish that look like a big fish arch.

And, it's also true that good FF pick up swimbladders. But that's not all. The good color Lowarances show the long arcs of big fish with their swimbladders. If FF's only showed bladders, then they would never show jigs or bottom contours since they don't have bladders.

So there you have it. Although it may not seem obvious, the next step is to figure out what to do once you've found the arches. My advice to most fishermen fishing LJ is simple: Pay Josh to learn the right way to deal with the arches.

My advice to you, Greg: Stop Fishing.

Oh, Ikrash. My settings are not a secret, I've laid out how I set my FF in this very post to Mike. I suggest you take off your blinders.

[GregAndrew]

Is there gonna be a test or can I just go on to Sonar 102? lol. Very kewl info there yani. I knew why the arches were shaped like they are, but I did assume that different densities of substance would give off different returns. I will take your last bit of advise under consideration on the next snow day in Palm Springs this month .

[cjthomas]

Thanks Yani for recommending the 728.

I saw your post (2 weeks ago) and started doing the research on that unit and comparable units. I basically found that this unit had the most power/pixels before you start paying a lot and upgrade to color. After my research I found one on e-bay for about 50 bucks cheaper than MSRP (I know no warranty, but I'll deal with Hbird if I need to) which fit my budget of a recently graduated college student.

As far as how any FF works, Lowrance has an excellent tutorial that describes with pictures and video how exactly they work and why we get arches.

http://www.lowrance.com/Support/Tips...onar-Tutorial/


I imagine the difference will be like night and day compared to my 100 (RMS) watt FF I'm currently using. PS: Don't be fooled by "peak-to-peak" measurements, they are a fancy way of making the unit look more powerful than it actually is.

[maui jim]

Thanks,This explains alot more than the manuals.
Looks like I almost had it figured out, but I had some doubts and questions but this clears it up.