Author Topic: Bright Line on Side imaging. (Read 31280 times)

mmikos · « **on:** July 05, 2014, 10:43:50 AM »

I have been having a consistent problem on my 899Ci HD SI. My stern mounted transducer is a compact side imaging one that came with the unit. It is mounted on the stern side on the bracket provided for doing so on my pontoon boat. The "interference is on the right side imaging lob. I would suspect this if the transducer is block. however there is a clear line of sight on this mounting and the engine is well astern of the transducer. Mounting the transducer on a pole and moving it from side to side switches the bright lines to the opposite side of the transducer. Again, this indicates a blockage of some sort. I can readily see the turbulence effects of the pontoons on both sides of the image. this effect abates as the speed is reduced but never goes away unless fully stopped. the bright bars remain whether fully stopped or not. the bars also remain with the 20hp motor up or down (no effect) on or off (no effect). Any ideas as what is causing this ??

mmikos · « **Reply #1 on:** July 05, 2014, 10:48:16 AM »

I moved the pole mounted transducer to the front of the boat and the problem disappears

I added a new HD transducer to a custom mount i made for the front of the pontoon boat. This is mounted on the starboard side of the boat (inside of a line for the starboard pontoon but forward of the pontoon). the new transducer produces a much smaller line on the port side imaging view. this line is 4 ' down and consistent. as before the mount is not blocked by anything and is 6 inches forward of the boat and all pontoons. Depth does not matter as the mount i created is adjustable up and down a full 2 feet. the line remains running either just below the water surface or down 2 feet. the picture below shows the new line

mmikos · « **Reply #2 on:** July 05, 2014, 10:49:38 AM »

and finally. the front transducer appears to just overload when i try the 800hz setting... frazzled in Penna.

Humminbird_Greg · « **Reply #3 on:** July 07, 2014, 10:32:00 AM »

Welcome to the Humminbird Side Imaging Forums mmikos.

There is a problem with the 899 units and the 800kHz sonar right now. The Engineering group are working on this.

On your new front mount: with the boat drifting, can you hold that transducer well under the boat and rotate it around to see if the line disappears or not?
Do you know of anyone else that has a Humminbird Side Imaging model unit (any model will work) so that you can cross-test your unit on their boat and their unit on your boat to see if the line stays with your boat/transducer or follows your unit?

mmikos · « **Reply #4 on:** July 07, 2014, 10:42:17 AM »

greg

thanks for the response. I will await a fix on the 800hz problem. To answer your question on the front mount. the problem remains but line switches sides if i move it to the port side. i.e. line is starboard of center same depths down. it does not go away even when well under the pontoon depth.. almost like an echo of the surface as it will show noise the same as the surface will do...will try to show a capture of this..

thanks again

mike

mmikos · « **Reply #5 on:** July 07, 2014, 12:59:15 PM »

here is an image that shows the line while looking like it is reflecting the surface clutter.

mmikos · « **Reply #6 on:** July 16, 2014, 12:01:27 PM »

here are some shots of my transducer mounting. It is well forward of the pontoons and i can see not reason for the reflection line in the screen shots above

mmikos · « **Reply #7 on:** July 16, 2014, 12:02:01 PM »

mmikos · « **Reply #8 on:** July 16, 2014, 12:02:54 PM »

Humminbird_Greg · « **Reply #9 on:** July 16, 2014, 12:49:10 PM »

Mike,
I’m stumped…
You stated that when you switched the transducer to the port side that the line switches to the starboard side of the centerline. That tells me that the problem is with the mounting as something must be blocking/reflecting some of the Si sonar signal – but your pictures don’t show anything capable of doing this.
Does this only happen when the boat is moving?
Did you find anyone else with an Si unit to cross-test with?

LocDown · « **Reply #10 on:** July 16, 2014, 07:02:05 PM »

Any chance you could move that to the back of the boat?

mmikos · « **Reply #11 on:** July 17, 2014, 06:59:59 AM »

greg

yes the line exist whether the boat is moving or not. I have not found someone to swap with.

Locdown

I have another SI transducer on the rear of the boat. I have a similar problem with it but on a much worse scale. I bought the new transducer to overcome it and could only find an absolutely clear site on the front. I manufactured the mounting which seems to work well

thanks for help

mike

Humminbird_Greg · « **Reply #12 on:** July 17, 2014, 10:27:59 AM »

I out of ideas Mike. The lines switch sides when you move the transducer to the other side but are also still there when you when you hold the transducer “well under the pontoon depth”. If it were the transducer or unit at fault the line would not change sides but you seem to have eliminated the transducer mounting as the culprit by holding it under the pontoons.

LocDown · « **Reply #13 on:** July 17, 2014, 08:33:14 PM »

Have you tried resetting to defaults? (grasping for stuff here)

mmikos · « **Reply #14 on:** July 17, 2014, 08:35:17 PM »

yes one of the first things that i did...no effect at all thanks for tryingthouugh

mmikos · « **Reply #15 on:** July 17, 2014, 08:40:54 PM »

with both transducers (front and rear) having this problem. rear one is much worse than front. I am beginning to suspect a problem in the head unit. i can move either front or rear transducers to either side and the problem with switch sides. the front transducers image is quite usable just not completely right. the rear transducer problem is quite severe in that most of the area under the boat is unusable in side image mode. there is no effect on 2d or DI images. very perplexing indeed.

Humminbird_Greg · « **Reply #16 on:** July 18, 2014, 08:50:22 AM »

But if the problem were in the unit the problem would not switch sides. The fact that it switches sides sounds more like an installation location problem but your photos do not show this and you said you had the transducer well under the level of the pontoons and it still showed the problem; which points to the transducer, but if it were the transducer the problem would consistently show on one or both sides – not switch sides…

kron · « **Reply #17 on:** July 19, 2014, 01:01:05 PM »

Quote from: mmikos on July 07, 2014, 12:59:15 PM

here is an image that shows the line while looking like it is reflecting the surface clutter.

(Attachment Link)

I don't know if this will help, but one solution "might" be too insulate the top of the transducer. As I have noticed before (Maybe not the case with the newer transducers though), the top of the transducer can receive a lots of signal reflections from the Surface. Maybe there is a double reflection from the aluminium pontoons as well? (I know the transducer is not mounted directly under the pontoons, but the pontoons are not strait angles - And therefor maybe directly reflective to the transducer).

Anyway. If this might be the problem, just try too insulate the top of the transducer with a sound absorbing material . e.g. Cork.

One more thing, Make sure you do not have a lots of electrical (inc the boat Engine) Equipment close to your sonar Cables, Unit etc. I have also heard and experienced problems with the power supply of the ground Unit. Try to power it with a separated battery (not the one being charged by the Engine) - This will probably only occur as a unclear sonar image, but who knows, might be a solution. If not then you at least got a tip.

mmikos · « **Reply #18 on:** July 19, 2014, 04:05:15 PM »

daniel

thanks for the advice. I agree with your assessment that the line is a result of a reflection of the surface..perhaps from the pontoons...they sure would reflect a beam....Not quite sure how i will insulate the top but willing to give it a try.

I pretty much eliminated the power source as a cause. I clipped directly to trolling motor battery without trolling motor attached.. I also moved head unit and insured no coils or parrallels...none of which made a difference. so back to original powering source.

thanks again for taking the time to contribute to the solution.

mike

newkid4si · « **Reply #19 on:** July 20, 2014, 12:40:23 AM »

Here is a post I saved from Rickard. It might help explain what's happening.

Charter Member

Rickard
location: Luleå Sweden

Re: Interference/Ghost signal on new 899
« Reply #3 on: Today at 06:20:32 AM »

Like Rickie says the SI beam may hit the surface, but it may also hit details on the stern even if they don't seem to obscure the beam. This is possible because the SI beam is not a single thin slice with sound as is shown in most sketches, it actually consists of a large number of thin slices which fill the angular space between the main beam and the plane of the piezo element. These sidelobes have much lower intensity than the main lobe has so they don't use to affect the image. This bundle with lobes act like one wide lobe that sometimes produces wide arcs around very reflective objects. If the stern has something very reflective on it, this can cause a line in the image similar to what jerklip has.

Rickard

Mike

mmikos · « **Reply #20 on:** July 20, 2014, 07:45:33 AM »

thanks again for the information.. I think that this is what it is. This line seems to reflect i.e. imitate any surface clutter that may be present. Do not know how to fix it but will cogitate a bit more on the problem

thank you again

mike

kron · « **Reply #21 on:** July 20, 2014, 09:39:18 AM »

Hi again. I'm not sure whether this will prove it is Surface reflections or not.

Maybe someone knows if this is the case for Humminbird or not:

So, what do I think? - The samples ( amount of sound Waves being sent out and received by the transducer?) is decreasing with increased speed and range.

This means that the resolution will be decreasing and the Bright lines should be darker?

If these statements/thoughts are true, then I suggest you to set maximum range (even though optimal is 3 times the depth) and drive faster then normal. If the lines turns up darker, then this theory might be true and the lines are Surface reflections.

Another trial and error I'm pretty sure will work to state there are Surface reflections is to submerge the transducer deeper. If the lines are reflections from the Surface you will get lines that are further away from the center line.

Finally if you want to insulate the top of the transducer I would just recommend you to buy some flexible Cork mat (rubber and Cork) and glue it to the top of the transducer (maybe use double sided tape?).

rnvinc · « **Reply #22 on:** August 28, 2014, 01:08:22 PM »

You might think about utilizing the AS SILR Y cable setup...

Mount the left HDSI xducer just port of the left pontoon...
Mount the right HDSI xducer just starboard of the right pontoon...

There will be no beams directed toward pontoons in this setup...

Rickie

buton · « **Reply #23 on:** October 06, 2014, 08:57:46 AM »

did you get to solve the problem?

mmikos · « **Reply #24 on:** October 07, 2014, 03:43:13 PM »

indeed i did... I posted on fishing board for anyone who had an old trolling motor that they wanted to get rid of... I received a reply from a fellow and for $20 I purchased the old trolling motor. I removed the control head and propeller and then replaced the aluminum shaft i had constructed with the old trolling motor parts and the high definition transducer mounted to the bottom of the trolling motor less propeller. this solved several problems that i had

1) it moved transducer several more inches forward of the pontoon..therebye clearing the pontoons even more than the previous mounting

2) it permitted me to control the depth of the transducer by moving it up and down with the shaft and securing knob. therebye lowering it even further below the pontoons when running and letting me raise it up out of the water whenever i wanted to take boat up on trailer. therebye clearing trailer bunks.

3) It had a kickback mechanism already built in should i hit anything while underway. this was a nice added plus.

4) Best of all It cleared the reflection line i was getting on my side imaging.

I believe it was the moving it forward and additional inch or two that did it. lowering the unit up or down had no effect on producing the reflection line.. So $20 and a little work cured all ills and added some benefits.

Now i just need to send my 899 unit back it to humminbird to get the 800hz problem fixed. I am waiting until fishing season is over here. I have to take my boat out of the lake marina by the 31st of this month and will arrange to have the unit sent back then.

mmikos · « **Reply #25 on:** October 07, 2014, 03:45:11 PM »

oh a i added a couple of images of the installation... to compare to the previous installation shown above.

buton · « **Reply #26 on:** October 07, 2014, 04:22:06 PM »

thats nice to hear.... please post some pictures of you new scans...

Jdeee · « **Reply #27 on:** October 07, 2014, 05:58:48 PM »

I had the exact same problem as you did with the line. I also had an almost identical set up with the aluminum square tubing that you used except it was mounted on my kayak with an electric motor and would start at speeds above a couple mph. I don't know if it was the aluminum or probably that it must have created a vibration that the transducer picks up at certain speeds it completely stopped when I mounted my 1198 the normal way on my new boat just like it did when you mounted it on the more solid trolling motor.

mmikos · « **Reply #28 on:** October 08, 2014, 12:27:55 PM »

here are a few..notice the bright line is long gone

buton · « **Reply #29 on:** October 16, 2014, 10:06:40 AM »

awesome pictures.... finally you got it...

newkid4si · « **Reply #30 on:** October 16, 2014, 08:58:59 PM »

Those are NICE images. Congrats.

Mike

Clackerbuzz · « **Reply #31 on:** October 23, 2014, 12:59:40 AM »

great fix idea mmikos. those pix are looking good. were you able to hook into any of those fish to find out if they were bass? i never see schools of bass like that in my water

only baitfish (white perch and crappie). but those fish look larger than bait

mmikos · « **Reply #32 on:** October 23, 2014, 05:53:40 AM »

striped bass

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