3 ms·

The Jindalee over-the-horizon backscatter radar in Western Australia has the reach and resolution for detecting a chunk of metal that size on the surface. Norm

The Jindalee over-the-horizon backscatter radar in Western Australia has the reach and resolution for detecting a chunk of metal that size on the surface. Normally it searches for contacts in a programmed grid pattern, sort of a random-chance game of finding bad guys ( HF backscatter radars don't sweep like UHF radars with which we are more familiar ). I'd hazard a guess that they programmed a radar search of the suspected area and when it found a contact they went and checked the satellite imagery. Spectroscopy from the image capture showed the object to be non-natural.

leoc 13y ago
If this is part of MH370 then you'd wonder why Jindalee didn't pick it up in the air. Just bad luck?
- simonh 13y ago
  At that time, nobody was looking for it. Unless you know to look out for something specific, it's just one more of the approximately 5,000 aircraft in the air at any one moment. Also these radars can have very narrow beam widths, typically half a degree. Suppose it was already being used for some other task?
  - leoc 13y ago
    But isn't Jindalee primarily an air defence system, intended to look for unidentified and unannounced aircraft?
    - ibmthrowaway218 13y ago
      With no active transponder MH370 would have been unidentified, and no communication with ATC would make it unannounced. It was also unexpected as there was no 'plane due to be in that area according to the filed flight plans (or every other one was identifiable).
- dingaling 13y ago
  Jindalee is marvellous, but unfortunately ( AFAIK ) it isn't possible to use it in a general surveillance manner. It needs to be directed to a specific area which it monitors; this is partly dictated by HF propagation conditions. Consider that it bounces its signal off the ionosphere to 'illuminate' an area on the surface. You can move that area around like a viewport but you can't make the viewport bigger. If the MAS a/c didn't enter the areas they were monitoring that day then they wouldn't have contacted.
  - leoc 13y ago
    Presumably the idea is to scan the search area in a methodical (though not completely predictable) fashion, like destroyers trawling the North Atlantic for U-boats?
    - dingaling 13y ago
      Yes, I think so! Or set-up a barrier-pattern of searching a linear range of areas continuously. I think they have four or five of these HF radars now, so they could co-operate.
snarf 13y ago
If it's an object that's still floating, it's more likely to be some sort of lightweight composite than metal. And if they are using this radar system in such a way, then they would presumably be able to use it to direct the search teams to the precise location in real time.

leoc 13y ago

If this is part of MH370 then you'd wonder why Jindalee didn't pick it up in the air. Just bad luck?

simonh 13y ago
At that time, nobody was looking for it. Unless you know to look out for something specific, it's just one more of the approximately 5,000 aircraft in the air at any one moment. Also these radars can have very narrow beam widths, typically half a degree. Suppose it was already being used for some other task?
- leoc 13y ago
  But isn't Jindalee primarily an air defence system, intended to look for unidentified and unannounced aircraft?
  - ibmthrowaway218 13y ago
    With no active transponder MH370 would have been unidentified, and no communication with ATC would make it unannounced. It was also unexpected as there was no 'plane due to be in that area according to the filed flight plans (or every other one was identifiable).
dingaling 13y ago
Jindalee is marvellous, but unfortunately ( AFAIK ) it isn't possible to use it in a general surveillance manner. It needs to be directed to a specific area which it monitors; this is partly dictated by HF propagation conditions. Consider that it bounces its signal off the ionosphere to 'illuminate' an area on the surface. You can move that area around like a viewport but you can't make the viewport bigger. If the MAS a/c didn't enter the areas they were monitoring that day then they wouldn't have contacted.
- leoc 13y ago
  Presumably the idea is to scan the search area in a methodical (though not completely predictable) fashion, like destroyers trawling the North Atlantic for U-boats?
  - dingaling 13y ago
    Yes, I think so! Or set-up a barrier-pattern of searching a linear range of areas continuously. I think they have four or five of these HF radars now, so they could co-operate.

snarf 13y ago

If it's an object that's still floating, it's more likely to be some sort of lightweight composite than metal. And if they are using this radar system in such a way, then they would presumably be able to use it to direct the search teams to the precise location in real time.