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Am I reading this right? Are the hugely knowledgeable (and most welcome) posters saying that the subsurface pinger signal may be subject to range extending effects just as HF radio waves are bounced/skipped off the ionosphere?
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CGB, yes, but that is the start of a new problem.
IMHO the Chinese ship may have gained a convergence zone contact and may well not have recognised it as such. It is the sudden signal loss which is a clue. If they held it for 15 minutes the first time, as 2 nm, then they may have been crossing the annulus. The 90 second contact may have been just clipping it. I did post about the deep sound channel a few days ago but it was modded out. |
Am I reading this right? Are the hugely knowledgeable (and most welcome) posters saying that the subsurface pinger signal may be subject to range extending effects just as HF radio waves are bounced/skipped off the ionosphere? Physics may not find MH370 but the laws it provides still do provide rational explanations for all manner of natural phenomenon which have come up as a result. Sadly the "laws" of human nature don't. |
It's interesting that the Chinese are always the first...
It's interesting that the Chinese are always the first to "find" something with regards to this aircraft.....first to spot floating "items" on their satellites photos now the first to "hear" the ping but did not record what they heard.
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Am I reading this right? Are the hugely knowledgeable (and most welcome) posters saying that the subsurface pinger signal may be subject to range extending effects just as HF radio waves are bounced/skipped off the ionosphere? At much lower frequencies, where passive sonar is used for submarine detection and tracking, signals can travel hundreds or even thousands of miles. They are refracted by the thermocline (an area of rapid vertical temperature change) a few hundred feet below the surface. In that sense, it is similar to tropospheric ducting of radio waves and perhaps a little analogous to HF ionospheric "skip" propagation. |
Originally Posted by Robin Clark
... which means that either the speed of the aircraft was changing , or it was turning fairly slowly left from its southerly heading. |
To summarise, the 37KHz pings heard near the surface (if true) indicate that wreckage is on the bottom somewhere nearby.
It is not, however, a simple job to narrow the search and determine an exact location because the signal could have bounced around in an underwater mountain range and been deflected by temperature and salinity layers. The next part of the job, therefore, is to get listening devices as deep as possible whilst avoiding collision with the mountains. This requires specialist kit and is not easy. This is going to take time and the batteries are nearing their end. It is therfore likely that a deep water sidescan survey will be required, the good bit is that the search area is now much smaller. When wreckage is eventually located it will still take months rather than weeks to recover anything using UAVs |
A black box detector deployed by the Haixun 01 picked up the signal at around 25 degrees south latitude and 101 degrees east longtitude. It is yet to be established whether it is related to the missing jet. From a ULD patent; Experience during past recovery operations has shown the range of the current conventional ULD design to be approximately one mile. |
To summarise, the 37KHz pings heard near the surface (if true) indicate that wreckage is on the bottom somewhere nearby. It is not, however, a simple job to narrow the search and determine an exact location because the signal could have bounced around in an underwater mountain range and been deflected by temperature and salinity layers. The next part of the job, therefore, is to get listening devices as deep as possible whilst avoiding collision with the mountains. This requires specialist kit and is not easy. This is going to take time and the batteries are nearing their end. It is therfore likely that a deep water sidescan survey will be required, the good bit is that the search area is now much smaller. When wreckage is eventually located it will still take months rather than weeks to recover anything using UAVs Well nothing's been found in the previous "areas of interest". If 25s 101e does prove to be the final resting place, there will be a lot of explaining to do by the likes on Inmarsat, and the Australian defense forces who's radar seemingly missed it |
Australian foreign minister on television: "nothing confirmed, please don't speculate and please wait until Angus Houston confirms one way or the other".
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RSCU75 is currently firing-up at Perth. It will be interesting to see the outbound track, perhaps indicative of the location of the Chinese ship evidence. Out of interest a Falcon 900 owned by a company associated with the AMSA SAR aircraft has been departing out of Canarvan to the west for extended periods for a number of days on a track consistent with the newer northerly search areas. It was apparent almost a day before any announcement was made that the search area had again shifted north by a significant amount.
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RSCU75 is currently firing-up at Perth. It will be interesting to see the outbound track, perhaps indicative of the location of the Chinese ship evidence. Initial track seems to be 284 degrees. |
Originally Posted by Airbubba
(Post 8420792)
Rescue 75 is now airborne. It is a P-8A from VP-16, the War Eagles out of Navy Jacksonville, Florida.
Initial track seems to be 284 degrees. |
I did read in the Chinese press that the ship was directed there by Australian authorities.
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Rescue 75 is cruising to the search area at FL325, I would assume this indicates MARSA.
From this morning's JACC media release: The Australian Maritime Safety Authority (AMSA) has three separate search areas planned for today about 2,000 kilometres north west of Perth, which total approximately 216,000 square kilometres. Weather in the search area is expected to be good with a cloud base of 2,500 feet and visibility greater than 10 kilometres. Reports overnight that the Chinese ship, Haixun 01, has detected electronic pulse signals in the Indian Ocean related to MH370 cannot be verified at this point in time. |
In addition, the Foreign Minister said that the report had come from a media reporter on the Chinese ship. As has been said its best to wait for confirmation by the search authorities.
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Tend to agree with the” firsts” for China in relation to all the findings. As already pointed out China appears to be doing its own thing. Why was the ship outside the search area and if it was transiting would it not be quicker to do so without a towed array or can it detect without a towed array.
Conspiracy well yes but not really. Would you wish to reveal just how good your radar etc was. I guess coming from a culture that when you are told, by Government, something you just believe it your mind set is that this is how other cultures operate. So it possibly would be expected that if a ship was operating outside the search area and it was just there cause it just was would not raise questions in this culture. |
acting autonomously?
. The decision to release the news via Chinese media rather than the Australian agency set up to co-ordinate the operation is likely to cause friction. CNN said an Australian source connected to the search said the centre had learned of the alert several hours earlier but had not been able to communicate directly with the Haixun. While other search crews report possible evidence connected to the flight directly to the joint research centre, the Chinese teams report it to Beijing first. |
Chinese patrol ship Hai Xun 01 searching for MH370
The Chinese patrol ship Hai Xun 01 does not want to have its location tracked since 23rd March
https://www.marinetraffic.com/en/ais...mmsi:412379930 |
China detection is fishy, so to speak
Agree but given the size of a search area it is unlikely to have been covered, particularly by towed array which also leads into my other query “Why was the ship outside the search area and if it was transiting would it not be quicker to do so without a towed array or can it detect without a towed array.” I suppose they might have found debris using a side looking mapping sonar, but again, pretty unlikely. Either the Chinese are extremely lucky, have undisclosed but very good intelligence as to the sunken wreckage location (not just surface wreckage), or are wrong about the report. BTW... after 30 days, the beacon output is supposed to be down only 3 dB (half power). |
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