¿ªÔÆÌåÓý

ctrl + shift + ? for shortcuts
© 2025 Groups.io
  1. QRPLabs
  2. Messages
Single Messages Topics Expanded Polls

Re: BBC news snippet mentions WSPRnet!

 

Hello Alan

I'd really love to believe it but still find it impossible to do so.?

All the maps in the document are criss-crossed by "WSPR links", many of which are marked as various types of "anomaly". At each 2 minute interval, he finds an "anomaly" line that exists near the place he expects the aircraft to be. Then says, well that's where it must be then. Which is based on it moving at a constant known speed, and in a quite straight line. Also if significant note is that his line tends to follow an existing flight corridor and surprise that's the route the aircraft took (they normally do fly along regular flight corridors). In tracking a plane that was totally not going in any expected direction you'd be in a very different situation.?

It is also worthy of note that as far as I can tell, nowhere in this document do we ever get to find out which band the anomalous WSPR links occur on.?

Any reported frequency drift (non zero) is a frequency drift anomaly. Of course normally it's the transmitter oscillator drifting or equally, the receiver oscillator. Or noise affecting the estimation algorithm.?

Most unbelievable of all: most (if not all) of the described anomalies are long path. This is not to say that the route of the signal received at the receiving station took the long path from the transmitting station. Which happens from time to time of course. But what we have here is that all those crossing lines are great circle extrapolations of the short path. In several examples the TX and RX stations are mentioned and look to be around 1000 to 2000km apart. This reported short path was reported in WSPRnet. But what is being claimed is that by some miracle an aircraft was in the way of this narrow beamlike signal on the LONG path, and that the aircraft perturbed the path enough to be noticed. How exactly can that ever happen? Even if the aircraft was somehow a perfect mirror which perfectly reflected the signal right back along the path it came... By the time it had traveled 10's of thousands of km and gone through 6 or 7 or whatever hops, how strong would such a signal be compared to the reported short-path signal? If it was 10x weaker than the short path signal, when added to the short path it would not change the report. A -15dB signal plus a - 25db signal is still a - 15db signal, given that WSPR doesn't report decimal places of the SNR estimate.?

So how can any kind of detectable "SNR anomaly" occur on a great circle extrapolation of the short 1,000km report of signal reception between the two stations? I'm just not getting it...?

I'd love to be wrong and for this research to be correct. It would be amazing and ground-breaking. It just feels to me so far beyond possible...?

73 Hans G0UPL
http://qrp-labs.com


-------- Original message --------
From: Alan G4ZFQ <alan4alan@...>
Date: Sun, Dec 5, 2021, 11:53 AM
To: [email protected]
Subject: Re: [QRPLabs] BBC news snippet mentions WSPRnet!
> I read the DJ4FF write-up. End to end. Twice. I searched for ZL2005SWL.
> But I still don't get it.

Hans,

So sorry, I thought I had found the reference I was looking for.

Mr Godfrey has done an incredible amount of work I am unable to
understand, let alone confirm his conclusions. I agree, much of his work
seems to be based on unproven theories and selective use of data without
clear scientific documentation.

I'm simply interested in the WSPR results, they seem to confirm aircraft
can affect signals over a long path.
Do we simply reject that as impossible or look for more evidence?

So far I have not found details of the Antarctic/ZL2005SWL tests. Maybe
there is not a comprehensive write up. Under ideal propagation
conditions they were claimed to have shown signs of Doppler/SNR
variations at times later confirmed by AIS data to be when aircraft were
close to the line of propagation. Note the waterfall was available for
visual signs.
The path is sufficiently clear of regular flights, reflections are
presumed to be more from turbulence/exhaust gases rather than from the
aircraft itself. It would be good to have the full story, were there any
"anomalies" when no aircraft were shown to be flying?

Here
https://www.dropbox.com/s/so2dobpyz4uutzp/GDTAA%20V2%20Blind%20Test%20Flight%2007092021.pdf?dl=0
? Mr Godfrey tracked by WSPR then path confirmed by aircraft.
Summary near the end.
This appears to show WSPR used for tracking, getting more difficult to
believe but still a question mark.

73 Alan G4ZFQ
Join [email protected] to automatically receive all group messages.