SUBSIM Radio Room Forums - Detection Range Glitch?????

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- - Detection Range Glitch????? (https://www.subsim.com/radioroom/showthread.php?t=93375)

Gosh, that's a long way... although it is in the surface duct itself. I suppose depending on the depth of the layer, this would be quite the echo chamber, although its even raining with a moderate sea state.

Well, I guess this is a good reason to test missions well.

Cheers,
David

Quote:

Originally Posted by Fish

About OKO's dark and light area's I doubth he is right there in his explanation.
When he first came with the idea the dark spots are hotspots for listening I did numerous test, but could not find prove.
On the other side, you could prove the opposite as shown in the pics below.

First a Seawolf listening at a worse place (light).

I conduct tests and you are right about this thing : "About OKO's dark and light area's I doubth he is right there in his explanation" but wrong about that one : "On the other side, you could prove the opposite as shown in the pics below"

I mean, the blue and dark area are NOT SNR relative ...

If you zoom out on an area where there is lot of blue/dark change (indonesia for example), then use SHIFT + I, you will see ... bright / dark areas are just hillsides of ground relief !
the lower depth is always at the separation.
So this is definitly NOT SNR relative.
I tought it was, from SC where you also have this feature, and didn't tested it from that time ! arfffff :88)
It's just to let you see better the ground relief because geodesics are not enought accurate, just a graphic feature !

Quote:

Originally Posted by Fish

SD=Surface Duct, and yes (Bellman) mud bottom.

Well, Fish, in SD, concerning the sound propagation for contacts in the upper layer, the kind of bottom have no effect.
For bottom limited of course, but also for CZ, where there is propagation under the layer, bottom is important.

It's different if contacts were under the layer of the SD ... but in the upper layer, it's a real concentration of the sound from emitter, snaking beetween the surface and the layer.

http://okof4.free.fr/images/DW/SDeffects.gif

In fact, 2 contact in the upper layer of a SD should have the best detection range you could find anywhere else, EXCEPT compared to 2 contacts in the same sound channel of a big CZ.

I'm finishing at this time a long mission (during a week) with CZ.
During the ingress I had contact at more than 40 miles for some minutes then they disapeared and reapeared at near half the distance.
CZ seem to be very well modelised.
1st detection at the longest distance you could detect something in DW, and second detection at less than the distance I could have detected the same contact in the upper layer of a SD.

With all due respect OKO, I am talking about LWAMI, not stock DW.
I learnt sonar from a real sonar wizzard, back in 688(I) Sub Command times, and am aware of the surfaceduct therefore. :know:
Still learning though. ;)