What !!? How could this man possibly tell the truth...?Posted by Roisin (here)
Supposing the Malaysian authorities [...] were not lying and were, in fact, telling the truth.
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What !!? How could this man possibly tell the truth...?Posted by Roisin (here)
Supposing the Malaysian authorities [...] were not lying and were, in fact, telling the truth.
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Last edited by Atlas; 6th April 2014 at 15:08.
Rocky_Shorz (6th April 2014)
Please describe, i do not understand the comment Buares, we must be looking at the pictures with different cultural lenses, because I do not see what you probably see from the comments - what is it?
No one seems to believe the "official version" of the Malaysian authorities. This is the minister of defence, he is the 'Malaysian authority' (in case of a terrorist/hijacking plot) and he is willingly and obviously lying to us and keeping us in the dark... (Forget about it, I was just kidding.)
Last edited by Atlas; 6th April 2014 at 15:33.
Flash (6th April 2014), Rocky_Shorz (6th April 2014), Roisin (6th April 2014), Snookie (7th April 2014)
Please keep in mind that the 'reception' of an underwater pinger is similar to receiving a radio signal but then even morePosted by panopticon (here)
Yeah, saw the same report. My interpretation of what Houston was saying when it came to comparing the visual and audio was to let the media know to back off and let the search teams do their job. The comparison was not meant, I don't think, to relate any similarity between the visual search and the signals detected other than there could be false leads that need to be treated carefully. He repeated a number of times that he would like unconfirmed reports to not be reported as fact so as to not harm the family & friends of those missing.Posted by Tesseract (here)
Was just watching the press conference with Angus Houston, he repeatedly tried to compare the difficulty in verifying an audio signal with that of verifying a visual signal - which is a complete nonsense. When asked what else could present a 37.5 kHz signal he refused to answer the question. When asked what was the frequency of the signal detected by the Australian ship he refused to answer the question, he was then asked again by someone else and admitted he didn't know that yet, and didn't even acknowledge that the frequency was of importance.
I agree that he didn't answer the question about what else could produce a signal @ 37.5 kHz (I thought that frequency was chosen because there wasn't anything else that uses it [natural or not]) however saying he refused to answer what frequency the signal was detected by Ocean Shield I think misrepresents what he said. He said he hadn't been advised what the frequency was however re-iterated that the signal detected was viewed as a potential lead. He also said that the information had only just been reported to him and he was relating it so as to explain why the Ocean Shield wasn't moving straight away to the Haixun 01's position.
-- Pan
complex. Radio signals fade-in and out because of propagation alterations especially when they are not received via
'line of sight'.
Radio signals bounce against all kind of objects, even layers in our atmosphere. Alterations in (some of) the propagation
paths may cause variation in the phase shifted components of the total sum signal that is picked up by the receiver. So at
1 point in time 2 components can amplify each other while at another moment 2 contra-phase components yield a 'no-signal'
result.
Acoustic propagation in sea water is even more complex. The waves on the surface will act as a very unpredictable reflection
screen. But there are lots of other influences too like change in salinity, temperature differences (inversions), currents,
difference in bottom composition etc. that change speed and direction of the signal. Perhaps this will give a better
indication why it could be heard over unexpected great distances, why the frequency might not be 'perceived' as exactly
37.5 Khz (changes in propagation speed) and why it is pretty difficult to get the direction where it is coming from.
That's why registering the signal with one hydrophone isn't sufficient you need an array with correlating circuitry and
software to make something out of it .... guess what's hidden in that big nose of those submarines ...
Drop off buoys are great to determine a search area but won't be able to locate the pinger exactly. Fading in/out signals
are an indication that they are not real close to the pinger.
Last edited by Operator; 7th April 2014 at 02:47. Reason: typo
Atlas (6th April 2014), avid (7th April 2014), Bill Ryan (6th April 2014), Elainie (6th April 2014), Flash (6th April 2014), gripreaper (6th April 2014), Jean-Luc (7th April 2014), mosquito (7th April 2014), panopticon (7th April 2014), psydney (6th April 2014), Rocky_Shorz (6th April 2014), seko (7th April 2014), Selene (6th April 2014), Snookie (7th April 2014), Tesseract (7th April 2014)
Last edited by Roisin; 6th April 2014 at 16:21.