Humminbird Side Imaging Forums
Side Imaging Forums => 997c SI, 998c SI & 999ci HD SI => Topic started by: mako9man2 on March 28, 2014, 05:54:17 PM
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I need a little help please. I just installed my HB 999si and am having a little trouble with the left side image. it is not as distinct/clear as the right side. Sorry no screens captures as yet. I installed a separate 2D transducer for high speed operation and it is tucked safely away on the far Starboard corner well in front of the SI transducer. Normally this kind of interference is caused by something partially obstructing the SI transducer. The SI is mounted just to the right of center on the transom and up about 4" from the hull bottom. There are three possibilities as I see it.
1. The engine could be blocking the signal but I have a 4" jackplate and when trimmed out the picture does not substantially improve.
2. Metal screen on the livewell pickup is located just to the left and below the SI but the SI sticks out about 1.5" behind the metal screen.
3. Metal ladder on port side. I guess this could be interfering but the bottom of the ladder is several inches higher than the SI transducer.
Here are pictures of the install. I suspect it is the Metal livewell screen but need some educated eyeballs before I go changing things. I can extend the SI farther back but not much lower otherwise the SI will induce turbulence directly into my prop at speed.
Thanks
[attachimg=1][attachimg=2]
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I would also suspect the livewell screen or the ladder (or both)...
Process of elimination is sometimes the best remedy...
Remove the livewell screen and test...
Remove the ladder and test...
Lower the xducer and test...
Temp mount the xducer to a pole and test completely below the boat ...
We have to remember the sound pulse extends all the way to the surface to the side ...so any obstruction that's in he water to the side of the xducer can cause blockage...
Rickie
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Thanks Rickie,
This site is really amazing in the depth of knowledge and willingness of members to help. I really appreciate it.
Checking/eliminating the live well screen will be no trouble but the ladder is just a bit more involved.
Just so I only have to do this once I want to understand how the SI operates. I know the beam scans side to side parallel to the transom of the boat. I read on this site that the beam does travel to the surface of the water so anything in that path could interfere. But how much area does the beam cover in front of and behind the transducer? For instance if this live well screen was directly behind and below the transducer say 2" would it cause any problems?
The picture I am getting on the left hand side of the screen is decent just not as crisp as the right side so at this point I am suspecting the ladder may be the bigger issue. The bottom of the ladder is higher than the live well screen but it sticks out a littler farther than the screen.
I'll let you know what I find out.
Thanks again
Joe B
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Here are Rickard's beam form depictions for the HB SI beams...
This is the view of the right SI beam from the rear...notice the upper side lobe reaches the water surface...(the left SI beam would mirror this depiction)...
(http://i477.photobucket.com/albums/rr134/rnvinc/HB/492EB491-D36D-46CE-9080-D6E601C82DB0_zpshmz3szda.jpg) (http://s477.photobucket.com/user/rnvinc/media/HB/492EB491-D36D-46CE-9080-D6E601C82DB0_zpshmz3szda.jpg.html)
This is the view the left and right SI beams from above (looking down)...
(http://i477.photobucket.com/albums/rr134/rnvinc/HB/20FA515D-842E-4639-B477-AB3F2FB2C39F_zpsui9c3cin.png) (http://s477.photobucket.com/user/rnvinc/media/HB/20FA515D-842E-4639-B477-AB3F2FB2C39F_zpsui9c3cin.png.html)
So basically anything to the side for the entire width of the housing and all the way to the surface can obstruct the sound pulse...
Although your ladder may not be able to be moved to test...it looks like you may be able to lower the xducer on your mounting board to possibly get the left SI beam low enough to "see" under the ladder...
But I would still test the livewell screen first as this looks like the easiest 1st test you can do...
Rickie
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Joe B,
Usually if it is something like the livewell screen or ladder there would be the tell-tale indicator of a constant vertical line that runs parallel to the center zero-line on the Si sonar View. It can also show up in the Di sonar view as multiple horizontal lines just under the surface of the water. Are you seeing this at all? Try setting the SI Range menu to its lowest setting and looking for it. If it is there it will show up with the boat drifting. If it only shows up when the boat is moving than it is turbulent water off the left side of the boat causing it. Please grab some Screen Snapshots the next time you get out.
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Thanks Greg
I hope to get on the water in the morning prepared to capture screen shots so I can post them for the experts. In preparation I removed both the live well screen and the ladder(not a big deal) so that my transom is completely clean. I'll adjust the 999 as you suggest and capture the result. I'll then add back the live well screen and retest. Lastly I'll put the ladder back on and retest. That should do it and I can then determine how to proceed for the best pictures possible.
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Good deal Joe.
Between everyone here we will get this figured out.
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Got on the water this morning and did the tests along with my first screen shots. I have concluded that neither the live well screen nor the ladder are causing any interference. I also determined that I can lower the SI transducer more and still keep it protected which I will do. Here are three (3) screen shots.
The first doesn't really have any significant structure in it but is does show the left side image quite a bit brighter than the right side. Almost washing out the image. This is what I was seeing the other day and don't know if this is normal or not.
[attach=1]
The next two screen shots are of roughly the same underwater structure. The first shot was taken with the structure on the right side of the boat and the second shot was with the same structure on the left side.
[attach=2]
[attach=3]
Ok guys give me some tips on improving the appearance of my screens.
Thanks a bunch
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Joe,
Are those taken in the 455kHz or 800kHz Si sonar frequency?
If not the 455kHz Si frequency, try it.
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They were taken at 800khz. I'll try 455 next time out. Now that I know how to actually take snapshots and record video I should be able to get much better pics to compare.
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Got back on the water today to try and get better SI images. Greg had suggested I switch from 800 to 455 which I did. WOW what a difference. I thought the 800 setting was for higher resolution images but in my case 455 gives a much cleaner image. I don't know if its due to the shallow depth I am using the unit in or something else.
Here are two Snapshots from today
[attach=1][attach=2]
Any suggestions for improving these would be appreciated.
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There is a software problem affecting the 800Khz in the 899.....don't know if the 999 has the problem or not. Call cusomer service and report the problem and see if it is a known issue.
Please let us know what they say.
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Talked with HB technical support about the clarity of my images in 800mhz. They suggested that I lower the sensitivity and manually set the SI range to about 25ft when in 7-10' depth. I did that and the images came out just fine. I was simply overpowering the image thus washing it out. I am now convinced that my unit and transducer are operating as designed I just need to learn how to adjust them for differing conditions. Now getting good scans in both 455 & 800.
Thanks to all for you inputs.