Humminbird Side Imaging Forums
Side Imaging Forums => 1197c SI, 1198c SI & 1199ci HD SI => Topic started by: Jerome2727 on January 03, 2013, 02:57:23 PM
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Getting interference on Left side imaging and downimaging as seen in the photos. Humminbird was of no assistance. Recommended to move the transuducer down, which helped minimally.
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As is usual with these HB transducers it does appear that your left si is hitting your boat keel.
Your choice is to move it down or put in two transducers (one for the left and one for the right)
chuck
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Keep in mind that an advertised sonar beam shape doesn't just go to the advertised angle (180° in this case) and stop..
The sonar beam is not a laser with sharp defined edges.... It's an ever decreasing sound pulse...
The sonar can pick up echoes up higher than the level of the Xducer "if" those echoes are big enough or close enough ...ie. your boat hull...
Rickie
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Thanks for the replies! I will try moving it further down.
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Just for S&G, could you try switching your down imaging beam to narrow and see if that changes anything.... if you havent moved it down yet
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Did yo manage to get a better image after moving the transducer Jerome2727 ?
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It helped maybe a little but didn't solve the issue, I'm planning on mounting a second transducer
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Anyone know what adapter I need to tie the two transducers together?
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I think you are getting echos from the rear sponsons. This would be why you are seeing the lines on the left as well. A two transducer setup is going to be the way to go. You can order the cable from Humminbird directly.
AS SILR - Y CABLE http://store.humminbird.com/products/323033/AS_SILR_Y (http://store.humminbird.com/products/323033/AS_SILR_Y)
Robert
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The image on the left looks very simalar to the issues I have had, I installed a second TD for no improvment. I returned the unit to HB and was told the main card is faulty. Its being replaced. Can you try your head unit on another boat ?
My down image was good though.
Ben
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I have the same interference on the front unit as well (998si) I also took the 998si from the front and hooked it up in place of the 1198 and had the same interference. I also changed out the transuducer with no improvement. Makes me think it couldnt be the transducer nor the unit itself unless i have two faulty units.
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When you say you “changed out the transducer” does that mean you tried a new transducer or just the one that was being used with the 1198 unit?
See if you can test at least one of your units on someone else’s boat to help determine where the problem is (units or transducers). This just has to be another Humminbird Si unit not the same models as you have.
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I replaced the transducer with a new one. Also took the 998 off the front and hooked it up in place of the 1198 with no improvement.
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If its happening on both units and also a second transducer, then its got to be echos off the sponsons!
Did you keep the old transdcuer? Mount it on a pole or 2x4 and see if you can put it down in the water well below the boat and see if you get the same result!
Robert
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I think I understand what you have done. You tested the 998 with the transom transducer and even replaced the transom transducer but got the same results, right?
Did you test your 1198 up on the 998’s transducer on the front and if so, what were the results? I’m thinking that the left side showed clear which points to an Si sonar reflection from the left side sponson as the cause. You will have to either get the HDSi transducer you have down lower in the water or hope that the second HDSi transducer on the port side of the motor works (I think it will because you are not getting a right side Si sonar reflection from the starboard mounted HDSi transducer).
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There are traces from reflections in the left view up to 10 feet from the transducer. Since the left sponson is closer than that I think some sound is reflected several times between left and right sponson before returning to the transducer. The total distance travelled could equal 10 feet. The sponsons look almost parallel which could facilitate such repeated reflections. I have seen such repeated echoes from wrecks, cars etc when sound has reverberated inside the object before returning. Even my towfish has caused such phenomena when sound has bounced repeatedly between a nearby object and the towfish body. Perhaps the problem can be solved in this case by covering the surface of the sponsons with a sound absorbing material? I would test by putting something that should interfer with the (hypothetical) between-sponsons-bouncing sound and look for any changes to the image.
Rickard
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Good idea Rickard but what would hold up in a marine environment like the transom of a boat?
Maybe some type of textured paint (thinking trapped air bubbles here along with a non-flat surface to reduce reflected sonar)?
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I really don't know what works. Perhaps a thick carpet with uneven surface would help. But the carpet would look and smell awful after a while... It could be possible to arrange with screening so sound is stopped in critical directions. Then the screen must withstand the forces from water at high speed. A simple "roof" that is mounted to the transducer and sticks out just enought to do the screening might work.
Rickard