Side Imaging Forums > 987c SI and 981c SI

New 999 unit depth reading error; graph vs dig reading

(1/1)

fishbone:
Had my 999 SI HD out for the first time and saw some goofy readings on depth.
One example was in 8' of water where the scrolling graph read 8' correctly while the digital desplay (block on the left side) read 18'.
Most areas it was correct, but under 8' the digital was unreliable.
Any ideas?

Also, when I pressed the "mark" button, a saved message would pop up, but the chart was never actually marked. I may have something not 'set' or enabled. Not sure.

Thanks.

Sorry, I posted in the wrong spot and can't move it.

rnvinc:
Shallow water over hard bottoms sometimes creates these type of issues ...

You can try Switchfire Clear under the Sonar tab and maybe turn down Sensitivity just a little ...
-----
-----
If Screenshots is Enabled under the Accessories tab and there is no SD Card in the unit ... The unit will err on actually creating a waypoint ...

Either insert a SD Card or Disable Screenshots under the Accessories tab ...

Rickie

fishbone:
The worse offending area did have a rocky bottom. Seemed strange one readout would be effected, but not another.
You are right again, I had no SD card in the unit. I'll correct that.
Thanks for the help.

rnvinc:

--- Quote from: fishbone on October 09, 2015, 07:18:12 AM ---The worse offending area did have a rocky bottom. Seemed strange one readout would be effected, but not another.
You are right again, I had no SD card in the unit. I'll correct that.
Thanks for the help.

--- End quote ---

Hard bottoms can allow the sound pulse to bounce more than once ... bottom reflection - surface reflection - back to bottom reflection - then to xducer ...("double echo" ...and sometimes "triple echo") ...

This sometimes confuses the unit as to which reflection the "actual bottom" really is ...

Switchfire Clear and reduced Sensitivity seems to be the best "workaround" for this specific scenario ...

Rickie

fishbone:


You can try Switchfire Clear under the Sonar tab and maybe turn down Sensitivity just a little ...
-----

[/quote]

It was already on Switchfire Clear. Which, or where, is the sensitivity that I can adjust down? Thanks

Navigation

[0] Message Index