Topic: 987c SI Image Problem

[bluebass]

I just got this unit about 2 months ago and really have not had much success with it..

I have noticed that there is an image problem on the right side..... I looks like most of the time...

My image is also grainy!!!

I also have alot of prop wash in my water colum!!

what am I doing wrong??

My transducer is installed In accordance with the instructions

Thank You

[reddog]

Put up a picture of your transom/transducer, and tell us a little about your settings...

[bluebass]

Beam - 200 khz
Side View frequ - 455 khz
Suface clutter - 1
Switch Fire - Clear
Fish Id - off
Fish Sensativity - 5
RTS Window - Wide
Bottome View Structure ID
Zoom Width - Narrow
50khz - 0
Depth Lines - on
noise filter - High1
Max depth - 25' (area fishing between 2 and 12 feet w/one 24' hole)
color bar - on
temp graph - on
DI beam - Width wide
SI mode - Both
SI sensativity - between 10 and 15
Range from  - 75 to 100
chart speed - 3
SI Enhanced - contrast 9 and Sharpness Off

[reddog]

Installation looks good, although it may be a little tail high..  Getting these things adjusted properly takes some time, and 1/8 " adjustment can make all the difference in the world sometimes.

The biggest thing that bothers me, is that your left side is problematic, which with a right mounted ducer, shouldnt happen, unless there is something wrong with the ducer, or unit..
  The interference in the water column, is bounce back from some obstruction on the motor..  It isnt a direct hit, but its enough to cause the problem.. Have you tried trimming up the motor to see if it goes away?  Try adjusting your DI beam width to something other than "wide"  9Not sure what the options are for a 987)

Do you have an "auto sensitivity" option on the 987 still?  I know they took it away in a software upgrade from the other newer units.

Try a few of these things, and take a screencapture at about 3.5 mph and your scroll speed to 4.  You need to base your settings on optimum  scanning conditions, and then  tweak them from there..    Something as simple as a softer bottom on the right, can cause darker images..

[Humminbird_Greg]

Looks like the left Si sonar is bouncing off the motor to me too reddog.  If trimming (or possibly trailering) the motor makes it go away, than you need to see if you can low the transducer down any further bluebass.

To running check the angle of the transducer (to see if the back-end is too high or not) try driving past a known vertical structure like a pole or a bridge piling.  If it does not get displayed straight out to the side you need to tweak the transducer.

Try testing your right Si sonar in an area that is flat and devoid of any structure if you can.  Shut the motor off and put it in the trailer position so that it cannot be blocking the left Si sonar. Than make a screen snapshot or two and compare the reading of the right Si sonar with those of the left Si sonar.  When you are making your running angle adjustments from above, make sure that the transducer looks level (left-right) when viewed from behind.  As long as your boat floats level when loaded and underway this should be pretty close way of making sure that the transducer twist angle (left-right) are correct.

[sonar2000]

These large HB transducers are subject to a lot of reflected energy. This is why we suggest getting as much information from other users before mounting and then when you do mount use a temporary means like double sided tape to get the exact spot.  Of course with the large foot transducer it does not always work well at above trolling speeds.
Cavitation being one of the most influencing ones..
Chuck

[bluebass]

Thank you for all the information...

I will be one the water in the morning and I will try I few of these suggestions...

I do though when I'm scanning have my motor trimmed up enough to get it out of the way.


Thanks again....

[bluebass]

These are the images i got Sunday, sorry it took so long to get them posted...

The 3rd pic is what it looks like with my outboard in the way....


Thanks again for all your input....

[reddog]

Again.... the best screencaptures are going to be at 3.5 mph with a scroll speed of 3-4.


Like Greg said in his previous post, find a relatively flat, non descript bottom to test in, because anything with any structure or even "texture" will affect what the screencapture looks like..

Picture #1, without knowing whether the bottom gets deeper on the far left, looks pretty good to me

,(#2) With the flat, non descript bottom,  the left side looks great, and as it should..  The right side, with the texture shown, looks good also..


Assuming on the 3rd picture, that you lowered the motor at the intersection of the clear and dark portion of the left side,(down towards the bottom of the image at the mph line) tells me that some of your problem is being generated by the motor, as suspected.

What sensitivity /scroll settings were you using in the second picture?


Did you try any of the suggestions above.  auto sens (if you have it)  down image beam width to something other than wide and changing the attitude of the transducer?


Not knowing what a "perfect screencapture" should look like, and its capabilities with a 987. its hard for me to tell you what you should do.