Help to decipher these images

[Coontakinta]

I'm having trouble working out the images on my NAVMAN FISH4600. After a lot of trial and error, reading and playing with the unit. I've worked out / been told to split the screen and zoom in on the bottom for a better picture of whats down there.

Thing is that this structure seems to look better in the full screen than it does in the zoomed half. For example on of the images below clearly shows something weed perhaps maybe something harder, but in the zoomed screen its all wavy, as if it was taken in a rolling sea

Then there is another image with something that appears clearly to rise off the seabed in the full screen shot but in the zoomed screen it appears to rising out of a hole.

I dont understand why the zoomed images appear this way. Can anyone assist with the why?

[ashh]

nevermind......I missread your post

sorry

[FNQCairns]

In the 'hole' zoom pic the sounders brain is a bit confused but with practice a person will just look through it. It all looks ok to me, your zoom is trying to show a better resolution so is not 'clumping' together the returns and forcing a marginally false bottom line.
You have a show of weed in each zoom pic, enough to drop a line to see what happens if the surrounding area was more barren.

Also your screen is too clean (but I do not know Navman) and more gain/sensitivity happening, need to dirty it up a bit, turn off as many of the automatic aids/filters as possible and get some mess happening, it might show a bit better then.

also do you have some sort of bottom line mode turned all the way up? Like grayline on lowrance, you may need to turn it down some, each use is individual as are the conditions, keep staring at it you will get there, I am trying to tune myself to a change of brand atm, it takes a little while.

cheers fnq

[Smithy]

I would be running in manual range not auto range. You can see the auto range has moved on you at inopportune times stuffing your picture. Always try and run in auto gain as well. The big give away that you are on good hard bottom are the tails below the redline. In your 2nd pick where it thickens up you were on hard bottom.

[Coontakinta]

Thanks for the advice Smithy & FNQCairns. I could be wrong here, but the unit is running in manual mode. I say I could be wrong because, whilst I have set it to run this way, I did not check before taking the pics and perhaps the unit goes to auto after being off. I dunno.

Presently the gain and sensitivity are set @ 8 or 9 from memory. This puts them @ around 40-60% I cant quite recall which. From memory full rating is 18 I think. Again I'm drawing from memory.

I know that the NAVMAN gear 8nt really upto scatch especially when one considers the price of some of this gear, but these appear to be flaws that I wouldnt have expected with my anceint Lowrance gear.

I will look into the manual / auto thing when next on the water.......hopefully this weekend.

[Smithy]

You might also be on bottom lock not bottom zoom as well. I think the giveaway is having a 0 as your baseline then the -15 below and the +15 above. Not familiar with Navmans enough yet to know. You could also be in manual mode but your range is in auto range. If anyone works it out, I would like to know how to change the zoom size in bottom zoom on the manual range settings. I prefer to operate in bottom zoom over bottom lock but other people prefer it the other way round.

[SgBFish]

Coontakinta.

I would push the bottom down the screen using the range function, you paid for the pixels in your screen and I would use them.

FNQ is right increase the gain even in 10M of water. The sounder is detecting things in the water but the filter is too high, therefore you are getting a clean screen. I would take the gain up too far then back it off.

I don’t use the bottom zoom function on mine. I mainly use the marker zoom and bottom lock.

[SgBFish]

Smithy are you talking about the Marker-zoom display range size on the Furunos.The mode that expands chosen area of the
normal picture to full vertical size of the screen on the left-half window. You may specify the portion to expand by operating the VRM (VariableRange
Marker), which you can shift . The area between the VRM and zoom range marker is expanded. As far as changing the size of the range I don't think you can...

Scott

[Coontakinta]

Thanks for the replys thus far. Guys I have tried adjusting the gain on the unit and find that its current setting seems to be about right as any higher seems to produce too much clutter. Hereabouts are some pics with the settings at 11 (50hz) and 18(200hz). With these settings I seem to be picking up a lot of floating weed.

Am interested in your comments so please keep them coming.

[Coontakinta]

I would push the bottom down the screen using the range function, you paid for the pixels in your screen and I would use them.

FNQ is right increase the gain even in 10M of water. The sounder is detecting things in the water but the filter is too high, therefore you are getting a clean screen. I would take the gain up too far then back it off.

I don’t use the bottom zoom function on mine. I mainly use the marker zoom and bottom lock.

Excuse my ignorance in these maters but, what is meant by pushing the bottom down? I tried changing the range on R/H side of the screen between 40 & 80 but in 60 it looked to be the best picture. I did find a horizontal line that is also adjustable to any depth. Guess this is usefull in determining the actual depth of bait schools etc ????? Also not sure how this affects the pixels

Can you explain the marker zoom function to me? What is it? I believe the bottom lock is most useful in rough conditions in helping to eliminate the rollypolly picture u'd otherwise get.

Again please excuse my ignorance with these matters. I've gone from using an old Lowrance X25 & X65 to this more technological equipment and to be honest with u. My lack of knowledge on this items is probably what got me into this mess in the first place. Shoulda stuck with a Lowrance!

[FNQCairns]

Hey! I see fish!!! it's a lot better now, some rubbish as well but fish! that last pic looks like there is a fair wack of interfearance from another boat/sounder/something anyway might leave that to the more experienced users here.
Where abouts are you sounding?

cheers fnq