Nice job Jerry! I am sure this will help lots of folks!
Thanks a heap Jerry, like others have previously said, I truly appreciate
what you have done. For me personally you have done two things. First, some of that technical jargon in the owners manual makes a little sense now, and secondly you have confirmed what I (and my wife) have been suspicious of for years… I really don’t know what the heck I’m doing out there! LOL
Jerry, I’m glad you were brave enought to write about this subject, not many
peolpe understand it at all, including me.
Now afew years ago my friend and myself did a so called test on my finder
and we were at the bank in three feet of water, holding my boat still and my
fish finder was scrolling fish and structure under the boat. I know there was no structure under the boat, I took a pole and went under the boat and found
nothing…:eek: And I had the finder in the right mode.
And how do you set the scroll speed ?, why are the fish not swiming toward
the the boat from the front or back?, what about tree leafs floating in the water?
It made me think about when America landing on the moon and played golf,
mybe that was a hollywood set to look that way so Russian government would go broke trying to catch up in the space race, which they did…:eek:
I believe it has little to no effect on the fish because of the frequency range the soundings are made. If it did I don’t think we would ever catch any fish.
This thread is an excellent candidate for the Archives.
Graphs don’t work very well in three feet of water. What you were probably seeing was surface clutter and/or electrical noise.
Not all graphs have an adjustable Scroll Speed and if they do it may be called something else. It’s probably in an advanced menu and it simply changes how fast processed information is moved across and off your screen.
I’m not sure what you mean about the fish swimming towards the boat as there’s no way to tell which direction a fish is swimming under the boat. All you can tell is whether or not they are in the view of the transducer.
Leaves, sticks, air bubbles and even microorganisms or anything else that a sound wave can bounce off of can show up on your graph.
Hey Don:
I don’t think the fish can sense the ping from a transducer and if they do they apparently don’t associate it with danger. I leave both my graphs on while hovering right over a brushpile and continue using them to monitor what is going on under the boat.
Hovering in the wind can be work. First of all you need to have your boat set up properly so you’re sitting comfortable facing towards the side of the boat you’re fishing on and have the handle of a hand operated trolling motor within comfortable reach. Having a properly place foot switch that you can step on when needed to run the trolling motor also helps and having a heavy, low profile boat is a plus. Then it’s just a matter of keeping the bow faced into the wind and using intermittent pulses from the trolling motor to keep you in position. If you do it every day you don’t even think about it most of the time. You start anticipating what the wind is going to do when you feel it coming and take preemptive measures so you’re not always trying to get back to the sweet spot. Now when it gets up into the 15 to 20-mph range it’s time to find a protected area out of the wind.
Thanks Jerry. Great Post! I have a Matrix 87c and Humminbird 585c & I have learned 2 things. I am running my sensitivity way too high & my scroll speed way too fast. Gonna do a little tweeking when I get back to camp tomorrow! I really believe I can “clean up” my display after reading your post!
Thanks! 
Can you explain the grayscale a little more and why would tthe screen speed ever be to fast?
Jerry Blake this thread may end up needing to have it’s on forum with you as the moderator…:eek: :rolleyes: 
Grayscale is Lowrance’s term for different shades of gray displayed on the screen to differentiate between objects by their size and density or how well they reflect the sonar signal back to the transducer. Harder and larger objects return the signal better or louder and show on the screen as darker shades of gray compared to softer or smaller objects. The LCX-17M displays up to 16 different shades of gray. Color graphs simply use different colors rather than different shades of gray to display the same information.
Grayline is another term Lowrance uses. This is from their web site:
“GRAYLINE®
This patented Lowrance feature helps you distinguish between hard and soft bottoms, where the thicker the gray band, the harder the bottom. GRAYLINE® also helps separate fish and important structures on or near the bottom from the actual bottom. Since more active-feeding fish hold close to hard bottoms and structures, GRAYLINE® helps you find more potentially productive water quickly.”
Humminbird has the same type of feature and they refer to it as “Whiteline”.
I guess your Scroll Speed would be too fast if it moved information off your screen before you had a chance to see it. Faster Scroll Speed is intended for faster boat speed so the graph displays what you just passed over and not what is a mile or two behind you.
Well, I have about 7-hours in it already. I was off today and needed something to do. 
I have trips scheduled for the next four days, ten trips in the next twelve-days, though so it will have to take care of itself for a while. I’ll get some pictures to add and maybe that will help.
Thanks Jerry for this post. It is very informative.
Thanks for asking Jerry. She is getting better everyday. Still having trouble keeping balance and walking. Should be better in a week or two. She has been asking to go, but my two year old is ALL about counting the fish on your website. We do it every night before bedtime. Got to work this weekend, but next weekend, I may try to make a trip over to Cane Creek with them. Maybe run into LA Stumpjumper as well.
Sounds like she’ll be ready to hit the water soon. I’ll be back on Greeson tomorrow and hope to have plenty for your two year old to count!
Second paragraph under the section “Transducer Frequency”, in this article:
http://www.boatus.com/boattech/SelectTransducer.htm
This, from a Furuno Color Depth Sounder article:
The airbladder of fish is what returns the echo to the fish finder. So the larger the fish, the larger the air bladder and thus the larger the target on your screen. Bait fish show up on the screen as a ball, because the echo is being returned on their collective air bladders. The air bladder on a single baitfish is too insignificant to return an echo, but as a school, their air bladders can be picked up by the fish finder. Remember, the denser the target the darker the color will be on your display.
This, from Pro-Troll.com article about using depth finder to selectively pick out fish species, based on their air bladder size/shape:
" Fish finders cannot read through air. Most fish have air bladders. The locator beam put out by your fish finder passes through water but cannot pass through air. Fish finders read the air bladder of a fish, and the image is bounced back to you."
And the Vexilar article, “How Sonar Works”:
http://www.vexilar.com/help/tips/tip011.html
And, I’ve read other articles that basically say the same thing.
I’ve used depth finders since the first “flashers” came on the market. It has always been “reported”, by these fish/depth finder mfg’s, that the signal is bounced off of “anything” that’s denser than water … be that rock, weed, wood, etc. They also state that the air, in a fish’s body, will interrupt the signal … and even “warn” users to not place the transducer where “air bubbles” (caused by turbulence) will pass over it, as this will create false signals or signal clutter on your screen (and, essentially block out some of the return signals … those of the “fish/cover/bottom”).
The “ping” doesn’t travel thru air very well … that’s why you can’t get a “bottom” reading, on your depth finder, when the boat is on land and the depth finder is still running. It’s “sonar” … not “radar”.
To answer your question about why we can see “waterlogged structure” -
The “other objects” (brush, trash, thermocline, rocks, etc) are “denser” than the surrounding water … and they reflect or absorb (change) some of the signal. That’s why we get their “picture” imprinted on the screen … the differences between the strengths of the returning signals are processed by the unit, into the pixel picture which you see on the unit.
… cp 
I would think that the body parts of a fish like muscle, bone or even scales would return a signal better than air in an air bladder. If air “interrupts” the signal rather than reflecting or returning it to the transducer then it wouldn’t be possible for the transducer to “see” it.
The transducer sends out a sound wave and has no way of knowing what part of that signal has been interrupted. All it can process is the small fraction of that signal that is reflected or bounced back from an object. I’ve dumped remains from filleted fish that no longer have any air in the air bladders over the side of the boat and they show up on the graph very much like live fish do.
When I have time to do some experimenting, I’ll tie a filleted fish carcass on a line without a hook or jig and suspend it under my graph to see what it looks like.
If a graph can “see” a 1/16-ounce jig I have no doubt it will pick up bones in a fish’s body.
It doesn’t really matter though what part of a fish returns the signal to the transducer. What is important is having the graph adjusted so it will display fish on the screen and for the operator to understand what they are seeing on the screen.
" Fish finders cannot read through air. Most fish have air bladders. The locator beam put out by your fish finder passes through water but cannot pass through air. Fish finders read the air bladder of a fish, and the image is bounced back to you."
I believe this. Cut the air bladder out of a fish and dangle it under ur sonar. Hard to see…Fish body bout like ours. Bout 98 to 99 % water. That why higher power sonar units haver better echo return than the lower wattage units. Too much power can be bad as not enough power… catch 22 here.
Kinda sounds like some of yous guys have been sitting in on my sonar classes…ha
Explain this…
We know that the right screen edge is the “real time” echo return and the display is nothing more than a history file. True.
Now, with respect to the cone angle, is what we first visually see on the display: the center of the cone angle, the front of the cone angle or the rear of the cone angle?
Good stuff,I wish all in life was that easy!!!:rolleyes:
