Topic: Down Imaging Issue 899 c SI/HD

[Green1]

Hi all. I am new to the forum and appreciate any feedback or expertise that can be relayed regarding my H’bird situation. I have a 899 SI HD and a 997 c SI that came with my used rig I bought. I believe all electronic installs were done by Cabelas when the rig was bought new.
Now, 2 years into owning this boat, I became unsatisfied with the side/down imaging detail and sharpness that the 899 si/hd was displaying. I am running the 997 in the front and it runs off the universal sonar on the Minn Kota fine in 2d. But, no having the cash for a new Mega unit, I decided to call Humminbird customer service. They explained that my 899 si/hd was running off a compact 455 khtz transducer – so I asked if a 800 khtz HD transducer would help the resolution and sharpness? She said yes, and I ordered a nearly $200 HD SI transducer for that unit.
I installed the new one as instructed and as close as possible to where the compact mount was. I have since been on the water two times and the 2d is fine (the same as it was before running off compact) and I believe the side imaging provides more clarity on the 800 signal. BUT, the down imaging is terrible. It is a super faint screen and does show bottom, but nothing resembling fish or structure marks. I have it set on hi def transducer and have tried both 455 and 800 kilohertz frequencies both. I have tried every imaginable color pallete and down imaging enhancement sensivity and contract imaginable. Still terrible reading on the down imaging. I have tried a direct connect to the unit(s) to rule out a problem with y cable and watched every You Tube video applicable on the subject. I have it set on 200/83 as well.
I have even tried lowering/raising the transducer on the mount and adjusting the angle.
Any ideas as what to possibly try next would be appreciated? Lastly, the 899 c HD should have the capacity to get better resolution with the HD/SI transducer – right?

[rnvinc]

Pre- HELIX Mega unit model SI xducers do not have a dedicated DI piezo in the SI xducer  ... the DI image is a computer generated image rendered from the data received by the SI piezoes  ...



So basically the DI image you are seeing is data received in the very outer fringes of the 2 side pointing SI piezoes  ...

Rickie

[Green1]

Thanks for the reply - I sure hope you didn't slice a 'ducer for my sake....
It does make sense and helps get perspective based on the technology. That said, the down imaging illustrations in the user manual and even simulation mode are SO much better than what I am getting now and just not sure why. ?
Do you think the compact transducer would give better readings than the hd SI that is on there now?
Any other potential causes as well?

Thanks much

[rnvinc]

Thanks for the reply - I sure hope you didn't slice a 'ducer for my sake....
It does make sense and helps get perspective based on the technology. That said, the down imaging illustrations in the user manual and even simulation mode are SO much better than what I am getting now and just not sure why. ?
Do you think the compact transducer would give better readings than the hd SI that is on there now?
Any other potential causes as well?

Thanks much

DI image quality would not change with any other SI xducer  ... the older core si xducers just do not have a dedicated DI piezo pointing straight down to get good returns from target directly under the boat  ...

Rickie