Author Topic: How do I get my unit to show Fish Arches?  (Read 6995 times)

0 Members and 1 Guest are viewing this topic.

Offline RGecy

  • Administrator
  • *
  • Joined: Mar 2009
  • Location: Beaufort, SC
  • Posts: 1981
    • SideImagingSoft.com
  • Unit(s): 1197c SI, 997c SI & 785c2
  • Software: 4.950 & 4.510
  • Accessories: Interlink & GRHA
How do I get my unit to show Fish Arches?
« on: August 19, 2011, 01:56:00 AM »
How do I get my unit to show Fish Arches?

No Arches
Consult the Common Checks guide and make sure that all categories are fully verified.

A fish arch forms as the depth sounder’s transducer moves over the fish. Due to the transducer beam angle the distance to the fish decreases as it moves into the beam, and then increases as it moves out. When the depth sounder graphs this distance change, an arch appears. The true depth of the fish is the top of the arch when the transducer is directly over the fish. Boat speed and movement greatly affect the shape and formation of an arch. When moving slowly or with a high rate of display update speed, a fish will create an elongated arch. With the boat moving at a fast speed or with a slow display update speed, the same fish will produce a much shorter arch. If the fish does not pass through the entire transducer cone angle, it will be shown as a partial arch. In any of these instances, the user may not recognize that the fish was shown as an arch. Please use the following suggestions to troubleshoot the problem.

Depth Sounder Will Not Show Fish
The Depth Sounder will show fish, and other targets, as groups of pixels between the surface and bottom. The following are factors that can affect the depth sounders ability to show fish. The Sensitivity or Gain of the depth sounder must be high enough that it will detect the return signal of a fish. Try turning the Sensitivity/Gain to a higher setting. For those depth sounders with the following features and menus, try adjusting them as stated:

    *  Fish ID Adjust - turn this feature OFF.
    * Water Type - set to present water type.
    * Sensitivity - all Sensitivity menus to a higher setting.
    * Surface Clutter - adjust so that less surface clutter is blocked.
    * (Noise) Filter – turn the filter OFF.
    * Transmit (X-Mit) Length - increase this setting.
    * Transmit (X-Mit) Power – increase this setting.
    * Turn off any other depth sounders.
    * Beam – turn all transducer beams on.
    * Contrast Setting – your depth sounder may have the ability to show weaker signals using one of four or up to sixteen different levels of Grayscale, the Contrast setting may not be high enough to be able to see weaker fish signals. Try selecting a higher Contrast setting to be able to see the weaker signals.
    * Bottom View - adjust to Inverse (Grayscale) so that weaker signals will be easier to see on the display.
    * Orientation of the Fish to the Transducer – a fish must pass through the transducers Cone Angle before the depth sounder can ‘see’ the fish and display it on the LCD. Fish that pass through the outer fringes of the transducer cone angle produce a weaker sonar return echo and, depending on the current depth sounder settings, may not be displayed at all.
    * Transducer Orientation - improper orientation of the transducer can cause the depth sounder to not ‘see’ fish. For a depth sounder to be able to show fish, it must have a transducer that is facing straight downward. Most transducers must also be oriented in a particular direction with respect to boat movement:
            * Transom Mounted - the pointed end of the transducer should be pointed towards the bow (front) end of the boat.
            * Inside The Hull Mounted – if the transducer is pointed (High-Speed type), insure that the pointed end of the transducer is pointed towards the bow (front) of the boat. If the transducer is round (Universal type), ensure that the side tabs of the transducer are facing the sides of the boat.
            * Trolling Motor Mounted – depending on the direction of the trolling motor, the depth sounder transducer may not pass over a fish in the correct orientation. This may cause the depth sounder to show only partial arches.
    * Boat Movement – both vertical and horizontal movement can affect a depth sounders ability to display a fish. If the boat is moving up and down, due to wave action, any sonar returns from fish may be scattered vertically and not be recognizable as a fish at all. If a boat is moving at a high rate of speed, the display speed of the depth sounder may not be fast enough to enable the depth sounder to display individual fish targets. All horizontal information will be compressed in this case. Also, some depth sounders have noise filtering or rejections systems that will not allow the display of a ‘random noise’ target. In this case since the boat is moving at a high rate of speed, the depth sounder may only ‘see’ the fish target once. This may not meet the depth sounders programmed requirements for a fish and may be rejected as random noise.

Depth Sounder Will Not Mark/Draw Fish With An Arch
The depth sounder will show fish, and other targets, as groups of pixels between the surface and bottom. Under the right conditions, the depth sounder will show these targets as an ‘arch’. It must be remembered that sonar shows a distance measurement only. The classic arch shape is made by a fish passing from the leading edge of the transducer cone, through the center of the transducer cone, and then through the trailing edge of the transducer cone. This will result is a series of distance readings that decrease to a minimum distance and then increase again. This is what gives the arch shape. The following are factors that can affect the depth sounders ability to show these targets by drawing an arch:

    * Boat Speed – with a boat running fast it is traveling across more bottom area and target information than when it is traveling slow. With the same Chart Speed setting as when the boat is moving slow, the depth sounder will have to compact any information it ‘sees’ when running fast. The depth sounder has a better opportunity to arch fish if the boat is moving at a slower speed. Also, when a boat is moving fast, small air bubbles may be getting under the transducer, decreasing the sensitivity of the depth sounder. Try slowing the boat or matching the boat speed with the Chart Speed setting.
    * Horizontal Boat Movement (Waves) – if the boat is moving up and down due to wave action, any depth (distance) measurements will be affected by the distance that the boat has moved farther or nearer to the fish. Any sonar returns from fish would be scattered vertically and not be recognizable as a fish arch at all. This would be like trying to measure your height while jumping up and down.
    * Chart Speed Setting – if the Chart Speed is set too high, the depth sounder will draw an elongated arch that may not be recognizable as an arch. With the Chart Speed set at a high setting, the arch may be spread across several screens. With the Chart Speed too low, the depth sounder may be drawing the arch but it may just look like a ‘blob’ of pixels shown all together. Again, try matching the boat speed to the Chart Speed setting. During field trials we have gotten reports that the depth sounders were not showing fish as arches. Setting the Chart Speed to a lower, slower setting ‘fixed’ the reported concern.
    * Depth Range Setting – with a large Depth Range setting the depth sounder may not be able to draw a recognizable arch on the display. This is due to the displayable resolution of the depth sounder at larger depth ranges. Example: with the depth range set to 0 - 300 feet, each vertical pixel on a depth sounder may represent approximately 11¼ inches. To show even a small arch at this depth range, a fish would have to be at least 22½ inches in height! With the same depth sounder and the depth range set to 0 – 100 feet, each vertical pixel would represent only 3¾ inches.Try switching to the manual depth range mode and adjust the display to show the smallest vertical area of the water column possible. Normally, the more vertical pixels that a depth sounder has to display sonar return information, the better ability it has to show a difference in vertical distance. It is this difference in vertical distance that forms the arch from a fish.
    * Sensitivity or Gain Setting – when the depth sounder draws a fish arch, the leading and trailing edges are lower and weaker than the center-higher portion. In order to show the beginning and ending parts of a fish arch, the Sensitivity/Gain must be set high enough to be able to show this weaker portion of the signal. Failing to set the Sensitivity/Gain high enough may cause the depth sounder to display the fish as a ‘blob’ of pixels that cannot be identified as a fish arch. Try increasing the Sensitivity/Gain Setting to enable your depth sounder to display these weaker sonar signals.

For those depth sounders with the following features and menus, try adjusting them as stated:
    * Fish ID Adjust - turn this feature OFF.
    * Water Type - set to present water type.
    * Sensitivity - all Sensitivity menus to a higher setting.
    * Surface Clutter - adjust so that less surface clutter is blocked.
    * (Noise) Filter – turn the filter OFF.
    * Transmit (X-Mit) Length - increase this setting.
    * Transmit (X-Mit) Power – increase this setting.
    * Turn off any other depth sounders.
    * Beam – turn all transducer beams on.
    * Contrast Setting – your depth sounder may have the ability to show weaker signals using one of four or up to sixteen different levels of Grayscale, the Contrast setting may not be high enough to be able to see weaker fish signals. Try selecting a higher Contrast setting to be able to see these weaker signals.
    * Bottom View - adjust to Inverse (Grayscale) so that weaker signals will be easier to see on the display.
    * White Line Setting – depending on the White Line setting and the strength of the returned signal, the depth sounder may display a fish arch that is not recognizable as such. The strongest portion of the fish arch may be displayed in Grayscale with a black line around it. Try turning the White Line setting to OFF.
    * Movement and Orientation of the Fish to the Transducer – a fish that does not move fully through the transducer cone angle may only show as a group of pixels and not an arch. A fish has to pass directly beneath and completely through the transducer for the depth sounder to be able to display it as a fish arch. Fish that pass through the outer fringes of the transducer’s cone angle produce a weaker sonar return echo and, depending on the current depth sounder settings, may not be displayed at all.
    * Depth of the Fish – an arch is the graphic display in the change in vertical distance as fish moves from the leading edge to middle to trailing edge of the transducer cone angle. The transducer cone grows wider the deeper it travels. The difference in distance from the leading (or trailing) edge of a transducer cone to the transducer and the distance from the middle of the transducer cone to the transducer is greater the deeper you go. So a fish that passes through the transducer cone angle at a shallow depth may not produce an arch, while the same fish passing through the transducer cone angle at a much deeper depth will produce a large arch.
    * Transducer Orientation - improper orientation of the transducer can cause the depth sounder to not ‘see’ fish. For a depth sounder to be able to show fish, it must have a transducer that is facing straight downward and not angled to a side or angled forward or backwards.
        * Transom Mounted - the pointed end of the transducer should be pointed towards the bow (front) end of the boat.
        * Inside The Hull Mounted – if the transducer is pointed (High-Speed type), insure that the pointed end of the transducer is pointed towards the bow (front) of the boat. If the transducer is round (Universal type), ensure that the side tabs of the transducer are facing the sides of the boat.
        * Trolling Motor Mounted – depending on the direction of the trolling motor, the depth sounder transducer may not pass over a fish in the correct orientation. This may cause the depth sounder to show only partial arches.

Depth Sounder Will Not Mark/Draw Full Arches or Marks/Draws Only Partial Arches
There are main factors that would cause a depth sounder to display only partial arches instead of a full fish arch. Three have to do with the alignment of the sonar signal to the fish, the forth deals with water conditions.

    * Proper Transducer Mounting Angle – a properly mounted transducer is critical for the depth sounder to be able to draw fish with a full arch.
    * If the transducer is mounted inside the hull, in a shoot through the hull application, then consider mounting the transducer on the transom of the boat, as there is no transducer angle adjustment available for a transducer that has been bonded to the hull of a boat.
    * If the transducer is mounted outside the boat, on the transom or trolling motor, adjust the face of the transducer so that it is parallel to the surface of the water. The face of the transducer should be pointing straight down into the water. Failure to use the proper transducer angle will impair the depth sounder’s ability to draw full fish arches.
    * Transducer Orientation – most depth sounder transducers have to be oriented in a certain direction, as they have a designed ‘front’ and ‘back’ end. Improper orientation of the transducer can cause the depth sounder to not fully arch fish. For each type of transducer, there is a direction that the transducer should be pointing with respect to the movement of the boat.
        * Transom Mounted Transducer - the pointed end of the transducer should be pointed towards the bow (front) end of the boat.
        * Inside The Hull Mounted Transducer – if the transducer is pointed (High-Speed type), insure that the pointed end of the transducer is oriented towards the bow (front) of the boat. If the transducer is round (Universal type), ensure that the side tabs of the transducer are facing the sides of the boat.
        * Trolling Motor Mounted Transducer – depending on the direction of the trolling motor, the depth sounder’s transducer may not pass over a fish in the correct orientation. This may cause the depth sounder to show only partial arches.
    * Movement and Orientation of the Fish to the Transducer – a fish that does not move fully through the transducer cone angle may only show as a partial arch and not a full arch. A fish has to pass directly beneath and completely through the transducer for the depth sounder to be able to display it as a full fish arch. Fish that pass through the outer fringes of the transducer’s cone angle produce a weaker sonar return echo and, depending on the current depth sounder settings, may not be displayed as a partial arch.
    * Horizontal Boat Movement (Waves) – if the boat is moving up and down due to wave action, any depth (distance) measurements will be affected by the distance that the boat has moved farther away from, or nearer to, the fish. Any sonar returns from fish may be scattered vertically and not be recognizable as a fish arch at all or only shown as a partial arch.
Humminbird Guru and Forum Administrator



Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo

 

Related Topics

  Subject / Started by Replies Last post
4 Replies
2990 Views
Last post April 09, 2010, 01:09:57 PM
by Humminbird_Greg
9 Replies
7205 Views
Last post May 05, 2010, 04:17:08 PM
by Wayne P.
2 Replies
3879 Views
Last post July 25, 2010, 09:46:24 PM
by RGecy
5 Replies
3693 Views
Last post June 20, 2012, 01:30:36 PM
by sjefsrafsern
17 Replies
5035 Views
Last post March 12, 2014, 03:27:59 PM
by Tjo
6 Replies
5144 Views
Last post August 19, 2015, 12:28:24 PM
by smallstk
5 Replies
3776 Views
Last post May 24, 2016, 11:22:41 PM
by RonnieB
8 Replies
1140 Views
Last post October 10, 2019, 11:18:42 PM
by rnvinc


SimplePortal 2.3.3 © 2008-2010, SimplePortal