This morning, in a Swiss newspaper, I read an article about the British aerospace engineer Richard Godfrey that believes to have found the probable location of the missing MH370 plane. The use of WSPR was one of his position tracking sources.
First I doubted that weak signal propagation can be used to track a plane and forgot about it. Later, somebody else made me aware of the story and I quickly looked at it again. To me it seems that it could be plausible, but I didn’t study the WSPR data.
Since I didn’t read about this story in the typical ham pages, I thought I’ll let you know about this somehow curious story.
I think it’s nonsense. Conflation of aircraft enhancement of vhf signals with wsprnet records for HF signals.
IMO, an aircraft can’t impact HF signal levels that are dominated by ionospheric reflections, not to any measurable effect on a 115 second integration time. No meaning other than ionospheric changes can be reliably derived from variations in reported signal strength from one period to the next.
Leaving aside the lack of the necessary VHF transmitting and receiving WSPR stations on either side of an unknown flight path that was probably into the Indian ocean where VHF enthusiasts are a bit thin on the ground.
There are many wonderful ideas about MH370. This is yet another. I agree with you that this one is off target. Yes HF radar can detect aircraft and track them but only because of some heavy duty engineering and software. Not 10 W to a dipole and a PC.
If someone was recording an hf beacon frequency and an aircraft crossed it’s path the df would possibly be detectable on a good system at the time. But it requires a graphic display of high resolution and a fortunate positioning of a powerful transmitter. Plus recording of before and after recordings of the signal Buckley’s and Nun mate.
Looking back at hf wspr records is going to be a real challenge. Actually more than that, Mission Impossible.
Studying ocean drift patterns and the many pieces of beached aircraft debris would be much better. This has been done and points to a crash site a bit to the North of the last search area. The Malaysian government has this information but sees no point in funding further searches.
The story presented is entertaining but that’s as far as it can go.
I’ve no comment on HF and MH370 but my QTH is south of the main flight path to Edinburgh airport and GB3CSB is to the north. It’s fascinating watching the Doppler on the 13cms signal as planes come and go.
Yes absolutely, that’s why I wrote in my initial post
In the PDF document How Can WSPR Help Find MH370? Richard Godfrey talkes about a software called GDTAAA (Global Detection and Tracking of Any Aircraft Anywhere)
and states in this document:
GDTAAA is a software system designed to detect and track aircraft using the WSPRnet data.
When a radio transmitter (Tx), aircraft (A/C) and a radio receiver (Rx) are all on the same great
circle path around the globe, then it is possible that the flight of the aircraft across the
propagation path of the radio signal can disturb that signal.
I didn’t read the whole document in detail and a quick search for this GDTAAA software didn’t give me more information or a deeper explanation.
So I’m still torn between it could be possible if one is really lucky and it’s completely BS.
I just like the fact that Joe Taylor’s WSPR tool, that is widely used by hams around the globe, found it’s way to the mass media.
The theory seems to have some support. In brief, the article in the link says WSPR signals are seen to benefit from aircraft movement and gives the example of flights in and out of Mauritius or Réunion coinciding with, as I understand it, improved SNR for WSPR signals passing these islands.
Nothing new though. Mostly hype and claims that nobody can disprove or otherwise. And all based on HF signals that have continuous fading and multipathing, spending most of their track well above flight levels. The ionosphere extends up to 150 km above ground, but flight levels are between 10km and 14km. WSPRnet records one signal level for each transmission, which could be the average, the minimum or the maximum. The single signal level from each 110 second transmission is what he is relying on. That transmitter might not transmit again for another 2, 4, 6, or more minutes, depending on the duty cycle selected by the beacon owner. So it is far from a continuous record. And its sensitivity to aircraft is unproven.
Validating this usage of WSPR data would require a series of demonstration flights with WSPR signal monitoring to be assessed independently to prove WSPR signal levels are responsive at all to aircraft crossing the assumed signal path.