Welcome Guest - Sign Up today
Welcome Guest - Sign Up today
Store Links Mobile - Shop Now

Announcement

Collapse
No announcement yet.

fish finders: fish id or arc

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Re: fish finders: fish id or arc

    Three sharks w/ramoras and a lone remora Just had to.
    When goals have no clear focus, neither will the actions of the people trying to achieve them

    Comment


    • #17
      Re: fish finders: fish id or arc

      Fishndirk nailed it. The term fishfinder is a marketing ploy only. The truth is that it's just a fathometer that's been adapted for us. It does use sonar by bouncing a signal off the bottom and then calculating the time it takes for that signal to be heard back. Fishfinders have different degrees of sensitivity and if you have a fairly good unit you can adjust that sensitivity and the frequency to see things that get in the way of the signals destined for the bottom.

      My Lowrance HDS 8 standard sonar is highly tuneable and I can adjust the sensitivity so that I can see fish arches and not all the other clutter or I can adjust it so that I can see the thermocline and use that instead of looking for arches. There is also a point of compromise where you can see both the thermocline and the fish and this is where most basic fish finders are going to be set.

      Lowrance also has structure scan sonar that uses much higher frequencies to produce a very accurate picture of the bottom. It's not a fish finder although if you train you eyes well enough you can see fish. Humminbird has side/surface scan that is probably more effective at seing fish in and around the depths of the thermocline. Of course the thermocline feeders are not every fish and may not be what your fishing for. That's why I went with the Lowrance HDS and use both structure scan and standard sonar to give me an "excellent idea" (pivotal phrase) of where I should be fishing and at what depth.

      Other factors such as surface temp and oxygen levels factor in because the natural food of the fish that you're going after will change colors depending on that. It's critical to know that info on lakes but not such a big factor on rivers and almost unimportant in Saltwater.

      Given all that, you can see that there's no way a fishfinder can accuratel choose between a fish and clutter. It may be 25% correct though and that may be enough if you learn to use the other factors well. I don't use the Fish ID function on my units if for no other reason than it's wrong 75% of the time.

      Comment


      • #18
        Re: fish finders: fish id or arc

        Not sure why this was moved as I interpret this thread as a fishing question not an electronics question. But I digress.

        There are a lot of assumptions made in this thread. dingbat makes some good points. But I have thoughts after covering the thread:

        Originally posted by Psandherr View Post
        That makes perfect sense and i should have thought of it sooner. Of course you cant use a fish finder to find fish only the cover that they would be in.
        All depends on what kind of fish and what kind of water you are fishing. Not all fishing is in cover.

        I use sonar to find fish all the time! I NEVER use fish ID as it obscures everything useful and makes my good resolution pointless if all I am getting is fish symbols. I use sonar to find fish when open water salmon trolling, and open water or off-structure oriented roaming walleye for example.

        There ain't no cover out there! I am looking for bait, and arches that indicate fish at certain depths. I also sometimes lower (at varying depths up to it's full 60' length) an electronic water temp sender and check temps at varying depths and choose which arches to target if that information gets my attention. I have marked arches while fishing and suddenly adjusted lure depth based on the depth of the arch and often this results in a fish being caught. It is not a fish-finder, as pointed out. It is a sonar I use to help me find fish.

        Originally posted by Psandherr View Post
        so for a basic unit with a small screen and gray scale would fish id be better
        Fish ID is never better. It is a waste of good sonar technology. You want to see the results of you echoes, not the results of what the software is deigned to interpret for you. As far as gray scale sonar: I use a 480x480 grayscale sonar. It doesn't show those huge marks dingbat mentioned. Only occasionally for probably the reason(s) other posters mentioned. I do not like color sonar- yet. I like HDS and "scan" units and think they are pretty cool tools but I don't want one. Just give me sonar! And think about this: it takes three pixels to display a color, while only ONE pixel to display "black." So my 480x480 is 480x480 pixels resolution on-screen. However, take your color 640x640 and you get only ~213x213 effective pixel resolution.

        Grayscale is better for general purposes. Structure scan I suppose has usefulness for bass or maybe some saltwater fishing. But as a troller for walleye and salmon and steelhead mostly my 480x480 helps me find fish. That, and it seems all the color units show those huge arches. My grayscale shows smaller, thinner arches. Often when walleye fishing I can predict the size of a fish if it hits as I have seen enough arches at "x" feet deep which were followed by a hooked fish that I now know what to expect.

        Originally posted by Jlawsen View Post
        ....you can adjust that sensitivity and the frequency to see things that get in the way of the signals destined for the bottom....
        Well, it is more than a fathometer. Most of what we enjoy for sonar today came out of technology originally brought "to the next level" during WWII with submarines. We have more tech on our boats today in that little box on the dash than the military did on warships in the 70s.
        Clean feet are happy feet; same for boats.
        1964 MFG Niagara Deluxe
        1969 MFG Edinboro

        Comment


        • #19
          Re: fish finders: fish id or arc

          Originally posted by Mark_VTfisherman View Post
          I do not like color sonar- yet. I like HDS and "scan" units and think they are pretty cool tools but I don't want one. Just give me sonar! And think about this: it takes three pixels to display a color, while only ONE pixel to display "black." So my 480x480 is 480x480 pixels resolution on-screen. However, take your color 640x640 and you get only ~213x213 effective pixel resolution.

          Each color pixel is made up of three liquid crystal color cells. The display resolution on color LCD panel is no different than a monochrome screen.

          BTW: Unlike the old days, increasing the resolution on an LCD display only makes things smaller. It has no bearing whatsoever on what you can see on the screen. 320 x 240 (QVGA)is more than enough for even a 6" display
          ....

          Comment


          • #20
            Re: fish finders: fish id or arc

            Originally posted by dingbat View Post
            Each color pixel is made up of three liquid crystal color cells. The resolution on a 480 x 480 ? (no such video standard) color LCD panel is no different than on a monochrome screen.

            BTW: Unlike the old days, increasing the resolution on an LCD display only makes things smaller. It has no bearing whatsoever on what you can see on the screen. 320 x 240 (QVGA)is more than enough for a 6" display
            OK. So then I have a follow up question: are the "pixels" different sizes on a color display unit?

            A Lowrance factory rep at a show mentioned that the grayscale units offer better definition than color units, and posters on another forum have mentioned this as well. As far as the arches being smaller- compared to my old sonar, I can see bait sometimes (in water under 30' and the depth set at 30 feet) that is discernible on my 480, whereas the old unit would show solid black for bait clouds or single black blocks for scattered bait if it showed bait at all. In clear water I have watched 2" minnows under the boat actually read on the sonar screen. That never happened with the old unit. Usually it would mark nothing. The 480 shows nice arches like old printouts I have seen from (now ancient) graphs that printed on paper.

            Anyway, really would like to know more on the color vs. grayscale issue. Most color units I have seen are no where near as "crisp" in displaying echo returns as the 480x480 unit is. That info certainly isn't in the sonar tutorial on Lowrance's website.

            Thanks, dingbat.
            Clean feet are happy feet; same for boats.
            1964 MFG Niagara Deluxe
            1969 MFG Edinboro

            Comment


            • #21
              Sign up today
              Re: fish finders: fish id or arc

              look at the spec for the pixels/inch to see what the pixel density is. Pixel density is the spec you are looking for.
              1998 Wellcraft Eclipse 24 Cuddy
              Volvo Penta Duo-Prop 7.4L "LK"

              2006 Sun Tracker Party Barge 21
              Mercury 90 4-Stroke FI
              "Common sense is not very common"
              "Failing to prepare is preparing to fail." -- John Wooden

              Comment

              Working...
              X