Reading sonar fish finders - Can it help our fishing?

Discussion in 'Stillwater' started by Drifter, Sep 5, 2013.

  1. I have been having a lot of fun with my new to me (used) sonar-gps fish finder and thought I would share!

    First, knowing the thermo-cline level really helps, when on anchor fish show up in lines because they stay in the finder cone for a long time.

    The thermal-cline level is where the clutter stops!

    These pictures are on anchor in a strong wind so the finder shows weaving in all the pictures from the boat going up and down, from the fish to the bottom. fish throw off a color with these color fish finders because they are a harder surface for the pings to bounce off! the bottom can also be seen as hard or soft by how much color or what color is shown and how deep the soft mud goes!

    This is salmon and steelhead in a stillwater above Bonneville that I have been fishing. when trout fishing the color is much smaller in the fish but is still there so you can tell weeds and other clutter from fish!

    In these photo's notice the thermo clutter from hot water ends at 6 or 7 feet! notice where some of the fish are! My guess was that the salmon were deep and the lines up high are steelhead moving slower, the blobs on bottom (school of fish) must of been moving much faster! Also when using sonar it's the depth of the signal (how deep it is not how long) or color that shows how big the fish are. reason why I figure the deeper blobs are salmon, much thicker signals!

    What depth would you fish at?

    sexi steal 049.jpg sexi steal 051.jpg

    Steelhead (stillhead) and Chinook with indicators in stillwaters!

    sexi steal 039.jpg sexi steal 036.jpg sexi steal 045.jpg

    Bartfly, aplTyler, GAT and 1 other person like this.
  2. Beautiful fish and a cool situation for sure.... I don't see a thermocline though.... it will show up as a faint. crisp horizontal line..... with the sharp water temp change the sonar will pick up the resulting density change..
  3. I see a lot of surface crud and bubbles. That's what the first 5 feet usually is. If the sensitivity is cranked up there's a lot of surface crud showing. If the sensitivity is turned down so the surface crud goes away it also does away with a lot of marginal fish returns.

    The second screen print looks like fish at two levels.
    Rudedawg and pond monkey like this.
  4. I'll start by hanging my bugs about an IRA length, and then move down a foot or so from there. After that I'll hang them straight down to 17' and hang on.
  5. You know what would be nice? An actual set of instructions on how to actually use the damned things. How hard would it be to include a CD or DVD with each unit that explained all the features and operation? I have 3 different units and have owned a total of 6 by now and not one came with adequate instructions. I'm sure I could figure some of that shit out if I just sat in my boat and scanned through screens but once I'm on the water there is just one thing on my mind and it ain't trying to decipher some electronic wet dream.

    They could do a hell of a lot better.

    Irafly likes this.
  6. I'm going to assume this is a Lowrance sonar. Lowrance has free classes at the winter sportsman shows. I've had 3 at the Puyallup show, 1 at Salmon University and 1 more more in depth one from the people who ran the ones at Puyallup. The latter two weren't free but the ones at Puyallup were.

    There's a lot of help a sonar/gps can give but most people don't use more than a 1/10 of what it will do.
  7. Yes mine is a lowrance and a very old model but the lowrance website also has a simulator down load that you look up your model and down-load a simlation of your finder, it gives simulated sonar readings and gps readings. it gives a picture of your finder and you use the mouse to key the buttons just like your finder in your boat so you can sit with the book at home on your pc. and practice! great feature!
  8. Lowrance is famous for their minimalist manuals..... you are almost your own..... there is quite a lot of help on the net though...including "Doctor Sonar"....he's a Lowrance guy...
  9. The book on my LMS - 339cDF IGPS IS 193 PAGES......
  10. "Minimalist" was not the best choice of words.... inadequate might be better.... my color Elite 5 X manual has about 40 pages.....and there is so much that is not explained....not just about that particular model but fish finders in general. They get complicated especially when one is not using "fish i.d." mode......... it's all fun though....
  11. Nice fish. Mark.
    Mark Kraniger likes this.
  12. Disturbance to 6' is just clutter. Thermocline will show as a normal screen to a certain depth, then horizontal color line, then back to normal screen... not just scattered garble. If I was to use something other than one of those Fishing Buddy finders, it wouldn't be Lowrance. Tough to tune even if you know what you're doing. Furuno!!! Here's how to detail the tuning of a finder......

    Edit: any finder will read well at 20', just play with the gain or sensitivy a bit.

    Tuning Guidelines

    So how do the Commercial/Charter and Sport fishing communities get the best out of their Furuno sounders, we will give up

    the process involved keeping in mind it is applicable to all Furuno sounders.

    1. Travel out to a common fishing ground and once drifting or anchored take the unit out of AUTO mode and have the

    display in Normal mode on 200 kHz. Now adjust range scale to get the bottom echo in the lower 2/3rds of the screen. As

    discussed if this is not possible due to the gap in a preset ranges adjust them to suit. Settings will more than likely be less

    than appropriate so don’t worry too much about the picture quality.

    2. Now bring the Clutter and Signal level/Colour Erase back to their lowest setting or OFF for the Greyscale units. Notice the

    picture is still viewable on the right hand side of the screen to observe adjustments. At this point the advantages of Clutter

    and Signal level/Colour Erase are not being employed and essentially the quality of picture is directly related to the Gain

    level selected.

    3. Adjust gain now back to its lowest setting and notice how weak the picture is (Even a powerful 600W RMS unit will

    demonstrate just how much amplification is involved in producing an ideal picture)! Increase it now to the point where

    clutter begins to occupy the screen. This is the point we want to focus on tuning, NOT reducing the Gain as with our

    competitors. Furuno’s processing technology will now remove the unwanted interference whilst providing superior target

    detection and deep water performance with the next steps.

    4. Access CLUTTER through the menu and increase it incrementally observing changes in the picture on the right of screen.

    For the majority of bottom fisherman the point at which to stop is when the interference is all but cleared except for a light

    scattering of the weakest levels of signal.

    5. Now increase the SIGNAL LEVEL/COLOUR ERASE in the same manner to clear the light scattering of interference and

    produce a perfectly tuned picture for that depth. Note: Increasing signal level/Colour Erase will make detection of prawn/

    cuttlefish etc difficult as they fall in the weaker signal groups.

    6. So with the tuning done it is simply a case of changing range scales and increasing or decreasing gain to suit depth. Now

    that fish and fish schools are easy to identify experiment with the TVG or DEEP GAIN settings increasing them to observe

    changes in the upper water column on the screen.

    The Furuno colour LCD sounders will respond best to tuning however good results can be achieved with the Greyscale range.

    Especially when operating at the limits of their respective fish finding ranges this process will show more targets and allow

    deeper performance capability.

    Combined with Furuno’s SALT water designed transmit/receive circuitry and ability to sustain RMS output power in deep water

    this is why Furuno have won more awards for sounders and sonar than any other company in the market place today.

    Shane Beardmore
  13. I was contemplating getting a fish finder for my kayak, but this whole discussion has been useful....I now know I don't want to spend the same kind of effort my 'home theater' sound system requires for successful operation.

    I guess after 50+ years of flyfishing and not having any damn idea what's really going on underwater...I'm now comfortable in my slothful ignorance.

    Dammit Jim, I'm a flyfisherman, not a piscatorial radiologist.

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