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  Reply # 1022699 10-Apr-2014 11:26 Send private message

joker97:
tdgeek: The concern is why are the ping detections not always at the same location? Whales? Dolphins?


This is exactly why. you are so confident but you have just said the pings ping from everywhere


Because of the pings detected, one may well be the real ping. Angus Houston is very conservative and he is now confident. This tells me that we see the news, but he sees the harder, detailed data

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  Reply # 1022761 10-Apr-2014 12:20 Send private message

6 pings from the oceans using a handful of ships, one of them is 100% the real deal? you sure about that?




Apologies for poor typing standards when on Samsung S4 [swype's fault]/iPad 2 Wifi[too slow to use!]

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  Reply # 1022762 10-Apr-2014 12:21 Send private message

i'd be more confident with 1 ping from 10 ships than 6 pings from 6 ships




Apologies for poor typing standards when on Samsung S4 [swype's fault]/iPad 2 Wifi[too slow to use!]

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  Reply # 1022819 10-Apr-2014 13:08 Send private message

Only one ship has the best equipment - the Ocean Shield.
Other ships are being deliberately excluded from the immediate search area to reduce noise pollution.




Sideface

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  Reply # 1022821 10-Apr-2014 13:09 Send private message

joker97: 6 pings from the oceans using a handful of ships, one of them is 100% the real deal? you sure about that?


Nope but watching CNN now, the pings travel a lot underwater which helps join them together. And some of those interviewed say that while there is other noise underwater, these detections can only be the pinger. The search area continues to narrow. The ping detections are non directional. The confidence of these experts and especially Angus Houston shows to me it is honing in with proper data

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  Reply # 1022849 10-Apr-2014 13:40 Send private message

As soon as they finish the triangulation using the outter ships and those 84 dropped buoys, the Bluefin-21 will be thrown overboard. Then we'll know they are sure of what they are hearing.

Seems the bottom there is covered in icky silt, and may not reflect well and be able to hide debris well.

An update on avherald indicates the life of the transponder may infact go longer than the estimated 30 days or so. But shift to less frequent and different frequency. It is just the min test period required for certification

The manufacturer of the underwater locator beacons (ULB), that were mounted to the flight data and cockpit voice recorders of MH-370, specified their ULB would transmit ultrasonic pulsed sounds at 37.5kHz +/- 1kHz at 160dB (re 1µPa). After a period of 30 days the ULB would still transmit at that frequency at 157 dB. The manufacturer did not publish any data beyond 30 days (certification criteria). Other manufacturers specifying their ULBs also at 160dB initially and 157dB after 30 days state the ULB would still transmit after 90 days though at around 150dB, the frequency drift may exceed 1kHz.

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  Reply # 1022851 10-Apr-2014 13:42 Send private message

Also the varying ping locations was explained. Noise bends on the ocean and travels further. A lot of math going on behind the scenes

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  Reply # 1022873 10-Apr-2014 14:03 Send private message

sittingduckz:
mattwnz:
Technofreak: There's now reports that MH370 didn't skirt around radar boundaries to evade detection.

http://www.thestar.com.my/News/Nation/2014/04/07/MH370-search-Indonesia-radar-CNN-skirted/?utm_source=dlvr.it&utm_medium=twitter

What do you believe?  If this has any truth to it then in my opinion the pendulum swings back to an in flight emergency rather than crew interference or hijacking.


You probably wouldn't believe a Malaysian news website over CNN. You don't know that these stories aren't just to increase traffic.


True, now an American news website on the other hand aren't at all interested in ratings, so they would never sensationalise a story tongue-out


Although they do have a reputation to uphold. If they provide incorrect info, then that damages their reputation. 

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  Reply # 1022878 10-Apr-2014 14:13 Send private message

tdgeek:
joker97: 6 pings from the oceans using a handful of ships, one of them is 100% the real deal? you sure about that?


Nope but watching CNN now, the pings travel a lot underwater which helps join them together. And some of those interviewed say that while there is other noise underwater, these detections can only be the pinger. The search area continues to narrow. The ping detections are non directional. The confidence of these experts and especially Angus Houston shows to me it is honing in with proper data


I'd have thought they can use doppler to measure frequency shifts depending on relative movement of the transmitter receiver. That way they get an indication of whether they are moving closer or further away and with careful planning they could take a series of measurements allowing them to plot straight lines at different points -- and in theory, where the lines cross will be a plane. 

At least, with the right math and signal detection and processing , allowing for signal variations too. 

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  Reply # 1022931 10-Apr-2014 15:08 3 people support this post Send private message

mattwnz:
sittingduckz:
mattwnz:
Technofreak: There's now reports that MH370 didn't skirt around radar boundaries to evade detection.

http://www.thestar.com.my/News/Nation/2014/04/07/MH370-search-Indonesia-radar-CNN-skirted/?utm_source=dlvr.it&utm_medium=twitter

What do you believe?  If this has any truth to it then in my opinion the pendulum swings back to an in flight emergency rather than crew interference or hijacking.


You probably wouldn't believe a Malaysian news website over CNN. You don't know that these stories aren't just to increase traffic.


True, now an American news website on the other hand aren't at all interested in ratings, so they would never sensationalise a story tongue-out


Although they do have a reputation to uphold. If they provide incorrect info, then that damages their reputation. 


Reputation ?  
When news services began leaving out context for political purposes they lost what reputation they did have.
In the "old days" you could trust the BBC for an impartial account, not any more.
Aljazera and Russia today actually play host to the broadest spectrum of news stories.
Western news is fast becoming a bad joke incapable of presenting facts without opinion, instead creating distraction with coverage of menial issues.  


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  Reply # 1022936 10-Apr-2014 15:10 Send private message

Marine Traffic - check out the website if you keen to look at the ships

gzt

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  Reply # 1023093 10-Apr-2014 20:14 Send private message

turnin: In the "old days" you could trust the BBC for an impartial account, not any more.

We had very few international news services back then so were in no position to judge. Yeah, they were the best going but even with massive depth overall they always had a strong UK political bias and apt to see the world through the lens of one party or another.

Aljazera and Russia today actually play host to the broadest spectrum of news stories.

Maybe, but don't forget Aljazeera consistently avoids saying anything to offend the Qatar govt which can at times include quite a lot of things.

RT is likely to be in a similar basket regarding Russian interests and has had some fairly crazy stuff on at times.

Here's just one link for RT, and similar also applies to all broadcasters mentioned for hot topics

http://en.wikipedia.org/wiki/RT_(TV_network)#Responses_to_RT.27s_news_coverage

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  Reply # 1023110 10-Apr-2014 21:00 Send private message

tdgeek:
joker97: 6 pings from the oceans using a handful of ships, one of them is 100% the real deal? you sure about that?


Nope but watching CNN now, the pings travel a lot underwater which helps join them together. And some of those interviewed say that while there is other noise underwater, these detections can only be the pinger. The search area continues to narrow. The ping detections are non directional. The confidence of these experts and especially Angus Houston shows to me it is honing in with proper data


you think the RF wave travel in a straight line in a 2 dimensional world (the piece of paper you draw on to calculate) and apply a straightforward doppler equation using the cosine of the angle and triangulating using pythagoras' theorem you hone in on the source. (or something like that i learnt at high school some decades ago)

i bet in a 3 dimensional world it takes more than just a cosine.

i bet the RF could well be refracted by the uneven density of the ocean waters as the depth alters.

even if there is negligible refraction i bet there are so many reflections that even if you get the 3D model of the doppler equation correct you have to apply a correction model.

i bet there are a lot of people smarter than me who are solving this - i hope you're right.




Apologies for poor typing standards when on Samsung S4 [swype's fault]/iPad 2 Wifi[too slow to use!]

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  Reply # 1023121 10-Apr-2014 21:19 Send private message

These are Acoustic signals not RF, and the salt water salinity, temperature, and subsurface geography means they don't behave quite like RF.

But as you've said there's good maths and smart folks well used to interpreting this stuff ( military and oil industry) so the skills and tools are o
available.

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  Reply # 1023123 10-Apr-2014 21:19 Send private message

I have already mentioned that pings bend in water. That refraction changes with depth and temperature. We all know there has been poor reliability on information. We know that Angus Houston is conservative, and if he has confidence that the aircraft debris will be located on the sea floor, implying sooner than later, that speaks for itself. The readings vary, some were up to 14km apart, that is viable underwater, again sound waves travel further underwater. Being non directional there is no option to triangulate, so the more pings, the varying signal strength helps them reduce the window. Further complicated that a signal may be weaker. Why? Could be further away, or it could be close and fading, it could be travelling less far or further due to conditions, all these variables. So if Houston goes from it could take a long time, to confidence that it will be found, implying sooner, yes I have confidence in that. 

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