The latest bit of news about the black box signal being reported in
Chinese newspapers injects a sour note and the Australian Search Centre
having to ask for information is disgraceful.
The Chinese do not seem to have instructed their vessels to report to
the Rescue Controller any and all information.
As the operation is in the area of Australia's Search & Rescue Zone
the searching vessels are under the control of the Search & Rescue Controller.
You can imagine the song and dance if the roles were reversed.

BTW, the reported pulse rate of 37500 pulses per second seems high to
me. Does anyone know what the rate is for these boxes ?

It is time for this whole exercise to be abandoned, it is costing millions to the taxpayer which we cannot afford, let's look after the living and not the dead, one does feel for the families of those on that plane, but enough is enough, like most reporting these days one has a tendacy not to believe what is being said by all the Governments involved in this search, they all know more than what you are reading daily in newspapers.
Secrecy is the order of the day now.

Hi Bazz

37.5 kHz is indeed the international standard for Underwater locator beacon(s) attached to the aviation flight recorders (Black Box). 37.5 kHz appears to provide a good compromise for detecting Black Boxes at likely water depths and have a reasonable horizontal range.

See http://en.wikipedia.org/wiki/Underwater_locator_beacon#Maximum_detection_range:

"A 37.5 kHz ...pinger can be detectable 1–2 kilometres ...from the surface in normal conditions and 4–5 kilometres...in good conditions. A 37.5 kHz...transponder pinger can be detected [presumable a horizontal or diagonal range? of] 4–5 kilometres...in normal conditions and 6–7 kilometres (3.7–4.3 mi) in good conditions."

My problem with Inmarsat's Doppler shift calculations are that they haven't proven useful in practice for MH370. I'm unconvinced about new, theoretical calculations that prove useless in being able to predict verifiable events - like MH370 crashing into the patch of the Southern Indian Ocean from which debris has floated into the current search area.

Still all those satellites, ships and aircraft are doing the best they can within these shortcomings (so far) of indicators.
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Hi Ojnab

While the Black Box pingers still have enough battery power (which I think may be up to 6 weeks(?)) I reckon the search should continue. So two weeks to go until they perhaps stop.

International relations (especially with CHINA) and legal expectations also count.

Regards

Pete

Hopefully the following is on to MH370's "Black Box" http://www.abc.net.au/news/2014-04-06/malaysia-airlines-mh370-black-box-event-signal-investigated/5370558 :

"A Chinese ship has twice detected a pulse signal with characteristics of an aircraft black box, while an Australian vessel is also investigating an "acoustic noise" in the search for flight MH370.
Retired Air Chief Marshal Angus Houston, who is leading the international search effort, said the second detection occurred on Saturday afternoon.

The Chinese [rescue] ship, Haixun 01, has picked up the pulse signal on two separate occasions within a two kilometre zone since overnight on Friday.

"This morning we were contacted by the Chinese authorities and advised that Haixun 01 had late yesterday afternoon redetected the signals for 90 seconds within just two kilometres of the original detection," he said.

"This is an important and encouraging lead, but one which I urge you to continue to treat carefully."...more...

OK Plantagenet, last that I heard was that Inmarsat has shifted its
area a bit south and the detection is in that area.
I would have thought that a better arrangement would be to have a
transponder so that it would just listen, less power, until it heard an
interrogation signal when it would leap into life.
The interrogating signal could be hundreds of watts and then the boxes
transmitter could be much higher powered as it would only be needed
for a much shorter time. Also once woken up it could transmit for say
5 seconds and rest for 55 seconds, that would extend its life many times over.
Anyway all very interesting but no hope there for the relatives.