Different compositions from FCV and TZT

Different compositions from FCV and TZT

Postby Aggeloseco » Wed Dec 27, 2017 7:10 am

Hello to everyone.
I am using currently the DFF1-UHD / TM265LH with the Maxsea professional software with the Sounder and PBG module. My main task is to record the Bottom Hardness as a cartography to my regions of Interest. Until now I had experience only over the FCV 588 with the p66 transducer.
The problem is that I get different Bottom Compositions from the 2 setups. I was recording yesterday in an area of depth between 70-100 meters, and I was getting in my TZ Professional with DFF1UHD/TM265LH setup too much sand as well as mud, and from curiosity, I switched the FCV588 with p66 on, which it was showing Gravel as well as sand with small percentage of Rocks. The TZ Pro, on the other hand, was demonstrating alternatively sand with mud and only in some small fraction of time small amount Gravel or Rock.
Does anyone know why is that happening, and which of 2 setups are more reliable?

The photos below are from the same spot.
Attachments
IMG_0198_Fotor.jpg
DFF1-UHD with TM256
IMG_0197_Fotor.jpg
FCV 588 with p66
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Re: Different compositions from FCV and TZT

Postby Snips » Thu Dec 28, 2017 11:03 am

Aggeloseco,
To be honest as the TM265LH is not in the UHD's database we haven't tested it to see how accurate the BD mode is using it. Yes it uses the same elements as the B/PM265LH but the performance is slightly different. As a test I would try the following, if you have the UHD programmed to use a B-265 try reprogramming it for a PM-265 and see if that helps.

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Re: Different compositions from FCV and TZT

Postby Aggeloseco » Fri Dec 29, 2017 10:20 am

OK , now I came back to Germany, I will be on water again in April , I will do so and let you know.
According to the B265, is it as accurate as the p66?
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Re: Different compositions from FCV and TZT

Postby Snips » Fri Dec 29, 2017 6:39 pm

Aggeloseco,
Never had a chance to test the two at the same time.

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Re: Different compositions from FCV and TZT

Postby Aggeloseco » Sat Dec 30, 2017 3:03 am

Ok
I also noticed that when I pass from the same point but from other direction I get different types of Composition, which they are entirely different. If you see my trails, there are crossings of sand and mud , or Rock with mud.
I dont know if this can be attributed to the TM 265 which is not in the UHD list.
Attachments
tzytr.JPG
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Re: Different compositions from FCV and TZT

Postby Snips » Sat Dec 30, 2017 8:56 am

Aggeloseco,
Hard to exactly say what is causing that just by looking at your track line. A couple of items to note when using the Bottom Discrimination mode. The BD mode uses both frequencies, even though you may be only displaying one. It is using the primary along with the secondary seabed returns. It is affected by the vessels speed so using it under 10 knots is recommended. It can be affected by turbulence, your screen shot of the FCV-588 is showing gaps in the seabed using 200Khz so it would be affecting 50Khz even worst. It is affected by the transducers angle i.e. it needs to be pointed straight down. On the Navnet systems it is affected by the draft setting. It can also be affected by what is in the water column. Usable depth range is 5-200m. Hope this info helps.

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Re: Different compositions from FCV and TZT

Postby Aggeloseco » Sun Dec 31, 2017 4:10 am

I Think my TM265 transducer is about 5° angle tilted towards right. I could be that this would cause the Problem, but again, would it show 100% Mud?
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Re: Different compositions from FCV and TZT

Postby Snips » Sun Dec 31, 2017 9:46 am

Aggeloseco,
Hard to say.
I know when I was conducting some early tests I mounted a transducer on a pole so I could change the angle and I did see a difference.

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