Lowrance recently asked me to have a look at the n

pabz0r

New member
Fishton.. don't you please want to do the carp guys a favour... hard and soft bottoms.. I can't tell the difference, im sure im not the only one.  What settings works best to distinguish between them. 
 

Fishton

Sealiner
DSI is great for detailed structure / cover, but not so good for bottom hardness.

200kHz does the best job when determining bottom type.
 

Fishton

Sealiner
The amplitude of the colorline/greyline determines bottom hardness. But you need to determine a reference first by going from a hard to soft bottom. The other way to check for bottom hardness is to double your depth range setting and monitor the 'second' echo. If the second echo runs parallel then there is no change in bottom hardness, if the gap gets bigger, the bottom is softer and if it gets narrower it is harder.
 

Foxhat

Senior Member
Hello Fishton,

You mentioned disabling the "WAAS" system, could you please elaborate on that a little. I haven't disabled my unit.

I have noticed as well as others on Sealine that sometimes our waypoints are a uniform distance out 20-30 meters on waypoints that we've loaded, not what we've taken on our unit.

It's a pain in the butt sometimes going in circles knowing that the mark is close by but not finding the spot using the co ordinates taken on an alternative unit.

Could this be caused by not disabling WAAS.
 

Fishton

Sealiner
WAAS (Wide Area Augmentation System) is used by U.S Aviation & Marine ONLY, and is not available outside of the U.S.

The reason for disabling it is that if the GPS reception drops too low, the system looks for WAAS, and it is in this transition that all systems fail when it cannot find WAAS.

I have never experienced my waypoints being out by 20 - 30m ... EVER!

I suspect that you made an error in the loading of your waypoints.
 

Foxhat

Senior Member
No, there's hundreds loaded and I anticipate the offset when locating old commercial marks. It seems to be North west of the mark between 20 & 30 meters.

When I bought my boat some time back I had an old Furuno GP32 and the screen was deteriorating, so I transferred about 400 points onto my work GP32 which was in good nick, I had the time, tedious yeah.

All the marks were out. I went through all the settings on the program and they were the same. The WAAS was enabled on both units. True North was selected with WGS84, I think.

I then bought the Garmin 526S and a Lowrance elite5 and I'm experiencing similar problems with older commercial marks.

I was under the impression that it could be caused by a simple incorrect selection of settings, that's why I asked. I remember others on previous forums on Sealine having similar experience and just thought with your advanced knowledge of GPS, that you had maybe an explanation.

The pilots that I work with suggested that inaccuracy of older waypoints could be attributed to settings on satelites that may have been altered.
 

Foxhat

Senior Member
OK thanks, yeah got that right, got the correct format!
When I eventually locate the structure, I take new marks and delete the faulty ones.
I tend to fish the same wrecks and structure regularly. I must comment on the clarity of the Lowrance unit but she battles in deep water.

These new finder/GPS units have a lot of info to digest.
 
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