lowrance x135

[ronnien]

hi all, i have got lines that are the same as the bottom but just up off the bottom, does anyone know why this is happing.

ron.

[littlejim]

Couple of possibilities. If you've got gain set really high, (or maybe if it's really shallow) you might be getting a second image of the bottom from the sound that bounces back off the surface down to the bottom again and shows up on the screen as a second image. Should be a fair distance between images. Lowering the gain (volume) should get rid of one image.

the other one is what an article by Fred Studden described as Late Scatter. Over hard bottom enough of the signal from the sides of the cone gets bounced back to the transducer to show up on screen. (Over soft they are too weak to show.) Because of the greater distance they have to cover compared to the centre of the beam, they show up later (deeper). It looks like a black hash below the bottom with a bit of a gap between the two.
Tried to PM a copy of the Studden article to you but can't see an 'attach' option. If you PM me your email address can send you a copy if you want one. His article is the only time I've seen this onscreen aspect of a hard bottom mentioned by an expert, despite buying a book or two on sounders.

[ronnien]

littlejim, thanks 4 that will have 2 wait till my better half wakes up (i dont know our email but willl do).

ron.

[Local_Guy]

can you post a pic

[ronnien]

local_guy, will post a pic but will have 2 wait till weekend.

ron.