WSPR Can’t Find MH370

Screenshot from WSPR software as developed by Joe Taylor (K1JT)

“I do not believe that historical data from the WSPR network can provide any information useful for aircraft tracking.”

Prof. Joe Taylor (K1JT), Nobel Prize in Physics, Inventor of WSPR

Despite many stories in the media repeating claims that historical WSPR data can be used to track MH370, there are many reasons why these claims are patently false. There is broad agreement among acknowledgeable researchers that have investigated these claims, and a handful of these researchers have documented their concerns. For instance, amateur radio enthusiast Hayden Haywood (VK7HH) has created a video explaining why, in simple terms, WSPR can’t track airplanes. MH370 investigator Steve Kent published a paper that formally treats skywave propagation and scatter off airplanes, and concludes there is insufficient signal strength (by many orders of magnitude) for WSPR to detect aircraft over long distances. In fact, even WSPR creator Joe Taylor (K1JT), who won a Nobel prize in physics for his research on pulsars and gravity, told fellow MH370 Independent Group (IG) member Mike Exner, “I do not believe that historical data from the WSPR network can provide any information useful for aircraft tracking.”

WSPR Background

WSPR (pronounced “whisper”) is an acronym for “Weak Signal Propagation Reporter”. Amateur radio stations implementing WSPR send and receive messages using low-power transmissions to test propagation paths on the Medium Frequency (MF) and High Frequency (HF) amateur radio bands. When a participating station successfully decodes the transmission transmitted by another participating station, it sends that information to a central database, and that information is available to the public for retrieval. For each 2-minute contact between stations (“spots”), the available information includes station call signs, locations, transmitted power, and three parameters discriminated by the receiver: signal-to-noise ratio (S/N), frequency, and frequency drift. The proposed theory is that recorded deviations (“anomalies”) in the (S/N) and the frequency shifts/drifts are related to radio wave interactions with aircraft some thousands of kilometers distant from either amateur radio station.

The theory behind using bi-static radar (i.e., transmitter and receiver in different locations) for aircraft detection and tracking is well-known, and books (e.g., this) have been written on this subject. A special case is when an aircraft crosses the “baseline” between transmitter and receiver, resulting in a “forward scattered” signal caused by the diffraction around the silhouette (projected area) of the aircraft. The Forward Scatter Radar Cross Section (FSRCS) is typically much larger than the RCS that conventional mono-static radar uses to detect targets. It is this forward scattered signal that is of interest here in evaluating whether WSPR signals can be used to reconstruct the path of MH370.

In this article we apply the well-developed theory of bi-static radar to demonstrate that WSPR signals cannot be used to detect MH370 in the manner claimed in this paper. The relevant equations are presented in the Appendix, and the inputs and the calculational results for the test cases can be found in the accompanying table in the Appendix.

Detection of MH370 Before Radar Coverage Was Lost

We consider the claim that the WSPR data shows that MH370 was detected on the night of the disappearance at 17:16 UTC when it was still under radar coverage as it flew over the Gulf of Thailand towards waypoint IGARI, before the turnback, at FL350 (37,200 ft). At that time, a WSPR transmission from a station in Switzerland (HB9CZF) was received by an Australian station near Canberra (VK1CH) over a distance of 16,527 km on 14.097 MHz at a transmitted power of 1 W. The distance from the Swiss transmitter to the aircraft was 9,868 km and the distance from the aircraft to the receiver was 6,660 km, as depicted in this figure from the paper:

Although WSPR contacts greater than 16,000 km are rare, this spot shows they can indeed occur. Based on the distance between the stations, the transmission from Switzerland reached the Australian station via skywave propagation in which the radio waves were refracted off the ionosphere and reflected off the Earth’s surface (“hops”) about 5 times.

WSPR Signals Forward Scattered from an Aircraft Would be Undetectable at Long Distances

The column labeled “Case 1” from table in the Appendix shows the inputs and the calculational results for this scenario. Assuming that the propagation loss is the same as for free-space propagation, the expected strength of the direct signal at the receiver is -110 dBm, which is about the same value claimed in the paper when considering hops between the ionosphere and the Earth’s surface. This suggests that the refraction and reflection losses were either calculated to be very small, or were neglected.

At 14.097 MHz, the wavelength is 21.3 m, and the FSRCS for the B777-200ER for waves directly incident to the top or bottom is estimated to be 18,791 m2, or about 23 times the projected area. The forward scattered signal at the receiver is estimated to be -210 dBm, or about 100 dB (10 orders of magnitude) weaker than the direct signal. Can a signal of this strength be detected and decoded by the WSPR software?

Whether the signal could be detected by the radio and decoded by the software depends on the achievable noise level, as a minimum signal-to-noise ratio (S/N) of around -30 db is required by the WSPR software, where the noise level is referenced to a bandwidth of 2.5 kHz. I ran some simple experiments on my Flex 6400 amateur radio to measure the achievable noise level on the 20-meter band at my home in suburban Roanoke, Virginia. At 10:30 am on December 19, 2021, on a quiet part of the band, when connected to a horizontal resonant antenna, and after setting the bandwidth to 2.5 kHz, I measured a noise floor of -102 dBm. This largely consists of manmade and natural noise received at the antenna. To determine the sensitivity of the radio independent of the environmental noise, I disconnected the antenna and connected the radio to a resistive dummy load of 50 ohms. The noise level dropped to -105 dBm. By using the radio’s built-in pre-amplifier configured for its maximum gain of 32 dB, the noise level further dropped to -129 dBm. (Pre-amplification improves sensitivity but increases the distortion from strong signals, and so must be used judiciously.) Even though this noise level would be very difficult to achieve under real conditions, I used this noise level as the reference for calculating (S/N) values on 20 meters.

So, for the forward scattered signal strength of -210 dBm, the (S/N) would be (-210 – -129) = -81 dB. This is 51 dB weaker than WSPR requires (-30 dB), i.e., the forward scattered signal is 5 orders of magnitude too weak to be detected and decoded by WSPR! Considering the very favorable assumptions we made regarding propagation loss, incident angle, and noise floor, we can be quite confident that the WSPR signal originating in Switzerland at 17:16 UTC did not interact with MH370 in any way that was detectable in Australia, as was claimed.

WSPR Signals Forward Scattered by an Aircraft Would Be Masked by the Stronger Direct Signal

Assuming the skywave propagation loss was equal to the free-space propagation loss, the WSPR signals originating in Switzerland and forward scattered by MH370 over the Gulf of Thailand would be received in Australia with a strength of around -210 dBm. However, the direct radio waves that did not interact with the aircraft would be received with a strength of around -110 dBm. That means that the direct signal strength would be about (-110 – -210) = 100 db (10 orders of magnitude!) stronger than the scattered signal. Under these circumstances, the combined signal (direct plus forward scattered) would be absolutely indistinguishable from the direct signal, even if above the noise level (which it was not).

However, the equations presented in Appendix A predict that it IS possible for radio waves to forward scatter from an aircraft and be detected under the right conditions. For example, Joki et al. studied how broadcast TV transmissions at around 50 MHz may be passively used to detect, identify, and track airliners over a distance of hundreds of kilometers. Some of the factors that determine whether the aircraft could be detected include:

  • The projected area of the aircraft
  • Strength of the direct signal received, i.e., high power transmitters near the receiver increase the signal strength
  • The distance of the aircraft to the receiver, i.e., the proximity of the aircraft increases the strength of the forward scattered signal
  • The frequency of the transmission, higher frequencies increase the FSRCS and therefore the strength of the forward scattered signal
  • Frequency-based signal processing to separate the direct signal from the Doppler-shifted forward scattered signal

Recently, amateur radio operator Nils Schiffhauer (DK8OK) claims to have observed aircraft scatter by analyzing the signal from an AM broadcast of China Radio International (CRI), which operates on 17.530 MHz with a 250 kW carrier, and uses a beam antenna with a gain of 25 dBi towards Europe. Nils’ location is near Hannover Airport in Germany, some 7,600 km away from the CRI transmitter in Xianyang, China. The figure below depicts a “waterfall” plot showing aircraft scatter over a period of 3 hours. The Doppler-shifted signals from many aircraft are clearly visible in the lower sideband (LSB), some 5 to 20 Hz below the carrier frequency.

Waterfall plot of CRI broadcast on 17.530 MHz as received by Nils Shiffhauer DK8OK in Germany over a period of about 3 hours. Evidence of aircraft scatter can be clearly seen mostly in the lower side band (LSB).

After processing the data from a 1-hour measurement, Nils calculated that the carrier strength was -59.1 dBm, the average Doppler signal strength was -105.9 dBm, and the average noise level was -108 dBm.

I was curious if the forward scatter equations in Appendix A would produce calculational results consistent with Nils’ measurements. After using FlightRadar24 to observe flights passing near his residence, I estimated that planes landing on Hannover Airport’s Runway 27R would generally pass within a lateral distance of about 2 km and about 0.85 km (2800 ft) above his residence, which is a slant range of about 2.2 km . A good number of those airplanes were B737s, which I used to calculate the FSRCS. The inputs and the results from the calculations are shown in the column labeled “Case 2” from the table in Appendix.

We know the location, power, and antenna gain of the transmitter, and since we know the received strength of the carrier was -59 dBm, we can calculate the additional propagational loss of the skywave path due to refractions from the ionosphere and reflections from the Earth’s surface, which we estimate to be around -33 dB. The signal strength of the aircraft scatter is then calculated to be around -102 dBm, which is only 4 dB stronger than the measured value of -106 dBm. Considering that the value of FSRCS is assumed to be in the most favorable direction, the measured strength of the aircraft scatter is entirely consistent with the calculated value.

Nils concludes that since the signal from the aircraft scatter is 47 dB below the carrier, it would be impossible to look at the combined signal (which is all that is available in the WSPR database) and determine the contribution of the aircraft scatter. We strongly agree.

WSPR Signal Deviations are Not Related to Aircraft

Based on the extremely small signal generated by a hypothetical interaction with MH370 at 17:16 UTC, there can be little doubt that at that time, the WSPR database did not record a spot between Swiss and Australian stations consistent with forward scatter from the aircraft.

Yet it’s claimed that there was a detectable deviation in the recorded (S/N) values between the Swiss and Australian stations that is indicative of forward scatter from MH370. To evaluate this claim, Mike Exner and Bobby Ulich produced the following graph which shows the (S/N) for all WSPR contacts between the Swiss (HB9CZF) and Australian (VK1CH) stations over an time interval of around 16 hours. The particular (red) spot deemed as “anomalous” clearly shows no greater deviation from the trend than any other spot. What is claimed to be “anomalous” is within the scatter range of the other points. The dynamic characteristic of the ionosphere is all that is needed to explain these deviations.

To further demonstrate that there is nothing anomalous about the spot at 17:16 UTC, Mike and Bobby produced the following graphs which show that the reported values of frequency and frequency drift at 17:16 UTC are in no way anomalous to the other values recorded on that day for HB9CZF-VK1CH WSPR contacts.


This article attempts to lay out in simple technical terms why WSPR data cannot be used to track aircraft over long distances, and certainly cannot be used to reconstruct the flight path of MH370. At long distances and at low transmission powers, the received signals from hypothetical aircraft scatter are simply too weak by many orders of magnitude. What is claimed to be discernable “anomalies” in signal strength attributable to forward scatter by aircraft are within the expected deviations in signal strength for long distance skywave propagation involving refraction off the ionosphere. Although aircraft scatter could be detected if the aircraft were close to either the transmitter or receiver and if the transmitted power were sufficiently strong, the detection of the aircraft requires signal processing to separate the Doppler-shifted scattered signal from the much stronger direct signal, and this data is not available in the WSPR database.


This article benefited from many private communications with Mike Exner, Don Thompson, Bobby Ulich, Steve Kent, Nils Schiffhauer, John Moore, and Ed Anderson. I also acknowledge the many insightful blog comments from Mick Gilbert, Sid Bennett, and @George G.

Update on December 22, 2021

I asked Joe Taylor for a comment on the material covered in this article. Here was his response, shared with his permission:

As I’ve written several times before, it’s crazy to think that historical WSPR data could be used to track the course of ill-fated flight MH370. Or, for that matter, any other aircraft flight…

I don’t choose to waste my time arguing with pseudo-scientists who don’t understand what they are doing.

Appendix: Equations and Table of Results

where the variable definitions and the inputs and results for the two cases can be found in the table below:

Reference: Passive Radar Technology, Prof. Charles Baker, University of Birmingham, NATO STO-EN-243-02.

101 Responses to “WSPR Can’t Find MH370”

  1. airlandseaman says:

    Victor: Thanks for taking the lead on this paper/blog post. It conclusively documents what so many knowledgeable experts have been saying from the very beginning: It is fundamentally IMPOSSBLE to track any aircraft in the SIO with historical WSPR data from March 2014. In fact, it is impossible anywhere on earth at any time. It is pure nonsense.

    It is (long overdue) time for the proponents of this WSPR fantasy to admit they were wrong, and to correct the record so we can get on with the real scientific effort to assist with the search. The viral spread of false information about WSPR has been harmful to 370 NoK, the amateur radio community and the public at large.

  2. Victor Iannello says:

    @airlandseaman: Thanks, Mike. The WSPR proponents are so dug in at this point that I think there is little chance of agreement. I simply wanted the opportunity for some of us to document (without leveling personal attacks) that we are on the right side of the facts, whether or not the blog article is widely read or understood.

  3. Mick Gilbert says:

    @Victor Ianello

    Thank you for that concise and cogent rebuttal of one of the key premises that GDTAAA is built upon. As you say though, this considered presentation of the facts is unlikely to dislodge the few who have adopted publicly entrenched positions on the ‘methodology’.

  4. 370Location says:


    It’s good to see this new critique on the claims for using WSPR to locate MH370. I hope the counterpoint gets picked in the news media, which has so far simply repeated the infinitely improbable bunk.

    I recently posted some analysis stats here looking for variations in drift by actual ADS-B position distance from a day of WSPR paths. The author posted a response on his blog. He then blocked my reply there, so my reply instead is … on Reddit, where hams are asking about WSPR:

    It was initially baffling that he would be insisting I wrote about planes flying at ionospheric altitudes, or his explaining ATC rules to prevent a high density of two planes every 5 km along flight paths.

    My guess is that he mistook my mention of only sampling planes above FL150 as meaning 150,000 ft instead of 15,000 ft.

    He also must have assumed that I somehow meant two planes for every 5 km along his great circle paths instead of laterally distant from them. Even though I described the 3-5K sample average number of planes aloft and up to 30 along his path, his interpretation would mean 16,000 planes along each WSPR path.

    I don’t think he was intentionally changing my words into a straw man argument, but genuinely misunderstood them.

    — Ed Anderson

  5. Victor Iannello says:

    @Mick Gilbert, @370Location: The technically astute will understand that WSPR can’t be used to track aircraft when the target is thousands of kilometers from either station, even with the most generous of assumptions regarding propagation loss, radar cross section, and noise floor. We are not inventing new physical principles–as such, we can perform the analysis using known theory with the most favorable of assumptions.

    I am not expecting a coherent rebuttal.

  6. ALSM says:

    Re: Claim by the former guy that I made up the quote from K1JT, here is one email, verbatim, received from Joe on Sat 5/15/2021:

    Hi Mike,

    This is nutty. There is no conceivable way that historical WSPR data could be used to track an aircraft.

    — Joe Taylor, K1JT

    So, technically it is true that Joe did not say “It’s nuts.”. He said: “This is nutty.” So, I apologize if anyone was misled by my error. lol

  7. Victor Iannello says:

    @ALSM: It’s very hard to dispute that crystal clear statement, but some will try.

  8. Victor Iannello says:

    All: Here’s what Joe Taylor told me today in an email when I again asked him for a comment on using WSPR to find MH370. I repeat his comments with his permission:

    As I’ve written several times before, it’s crazy to think that historical WSPR data could be used to track the course of ill-fated flight MH370. Or, for that matter, any other aircraft flight…

    I don’t choose to waste my time arguing with pseudo-scientists who don’t understand what they are doing.

    I think that sums it up nicely.

  9. Mick Gilbert says:

    @Victor Ianello

    Re: “I am not expecting a coherent rebuttal.

    And you wouldn’t have been disappointed. A rambling shambles of same old, same old.

    We’re initially treated to an episode of the misplaced use of a common character trait between open and closed boiling vessels as a means of ironic disparagement. Of all things, we’re treated to a critique of the Independent Group for having made multiple assessments of possible crash locations over the years. No one has published more papers claiming a greater number of crash locations over the years than he has. By my reckoning he has pinpointed the crash site variously as far north as 19S, 23S, 26.9S, 30S, a couple of stabs in the 34s (34.23S and 34.4S), as far south as 35S, and also 37S. There’s possibly more, I lost track sometime back.

    We’re then told that the “challenge” to download live or historical WSPR data and test it hasn’t been taken up. Bullshit! Many of us have looked at the historical data and demonstrated that there is nothing discernible in it. Unless I’m very much mistaken, you have done exactly that with the HB9CZF-VK1CH data in the example detailed above. Talk about none so blind!

    And speaking of blind, the author of Gaussian Distributions Trashed and Associated Analytical Atrocities says that the blind test with QF6036 has been ignored. More bullshit. It hasn’t been ignored at all. To the contrary, when some of us looked at his “position indicators” in that test, for seven of the nine for which there is ADS-B data, we found that none of his guesses were correct. The aircraft had barely travelled 130 kilometres from the known take-off location and his first “position indicator” was in error by over 35 kilometres! His methodology routinely fixed the position of the target aircraft where the actual aircraft demonstrably was not. This abject failure of the methodology to do what it was meant to do was hailed by the “adjudicators” as highly successful. Makes you wonder what subterranean depths needed to be plumbed to slip under the bar for failure.

    Then we’re told that Dr Robert Westphal’s Geocaching in the Ionosphere paper has been ignored. More bullshit! The shortcomings in that paper have been addressed. When it was pointed out to Dr Westphal that regards his examples of the Davis Station helicopter operations and the Qantas Antarctic sight-seeing flight being “detected” in WSPR links between Australian transmitters and New Zealand and Japanese receivers respectively, in neither case were the target aircraft anywhere close to the propagation paths between the stations, he responded that,

    … the WSPR signal from DP0GVN in Antarctica, assuming an isotropic radiation in all directions, hit the helicopters at Davis and was scattered amongst other directions to ZL2005SWL in New Zealand.

    Utterly impractical, but if it were true then it would mean that Guessing, Doodling and Tracing yada yada yada could not work. If WSPR signals that have been scattered off targets that are not on the great circle propagation paths can register in the received and recorded spot data, then it is not possible to discern the location of the target. In fact, you’d have no idea which or even how many targets you were dealing with. It is beyond astounding that the author doesn’t understand this – if Dr Westphal is right then he is wrong.

    Of course, all of this to and fro can easily be resolved. If he is so sure of his work let him submit it to a peer-reviewed professional journal such as Nature or Radio Science. We’ll wait.

  10. Mick Gilbert says:

    … pseudo-scientists who don’t understand what they are doing.

    To quote ET, “Ouch.”

  11. Victor Iannello says:

    @Mick Gilbert: What he refuses to acknowledge is that his theory fails even with the most favorable of assumptions.

    Regarding the Qantas test flight, an earlier version of the article addressed the absurdity of this result, too. The signal must pass over one station, propagate thousands of kilometers to reach the plane, backscatter, then propagate back thousands of kilometers to reach the receiver. So in this case, the “anomaly” is determined by comparing it to what? If there is no aircraft, there is no backscatter. So is the base case the short path between the transmitter and receiver? I couldn’t make any sense of what was claimed, so I elected to just include the MH370 at 17:16 UTC because we do have ground truth at that time.

    There’s also a lot that could be said about the unscientific methods used by the arbiters of the Qantas blind test who proclaimed the test was a resounding success despite the obvious shortcomings.

  12. … thanks, Victor, for your work. I think it somewhat brave to bother K1JT with this topic, although I know from personal communication with him that he has a great ear for radio amateur‘s questions, answering them patiently …
    He now should have had the last word in this dead case. Charlatanry or pseudo-science is the right commentary to what [was] presented. Any time spent to publish more data and scientific arguments is wasted. It is not a case of science, but, as I said before, social-psychology. Also interesting, but not to be discussed here.
    73 Nils, DK8OK

  13. Victor Iannello says:

    @Nils: Thank you, and I won’t be bothering Prof Taylor again on this topic. I think it would be interesting to perform scientific experiments to quantify the aircraft scatter in the HF bands under various conditions, but those experiments won’t lead to a methodology for using WSPR data to find MH370.

  14. Nils Schiffhauer says:

    … thanks, Victor, and I strongly support the idea to investigate how amateurs can receive and analyze aircraft Doppler. For a serious approach, another mode is needed. We can already start with analyzing the relative difference of time of flight through different paths, including aircraft scatter. This can be done within a minute using STANAG4285 transmissions around the world and (graphically) analyze their pseudo-random numbers with free software PSKSounder. This already had been done for many years, without attracting too much interest among the community. We now have modern technologies at hand, making use also of worldwide synchronized networks by GPS et al. Propagation Committee of RSGB had set up an interesting net around 5.5MHz many years ago, but it also didn‘t attract too much interest among the mainly conservative community. A fresh approach – proper mode, plus transmitting and receiving network- would spark qualitative analysis (absolute time of flight, phase, amplitude, number of paths etc.) is very much needed. I tried to interest some amateur radio societies for such an approach but to no avail so far. New Year, new chances … 73 Nils, DK8OK

  15. Nils Schiffhauer says:

    … Sorry for a P.S.: Since more than a decade there already is existing a worldwide professional network of Digisondes for exactly measuring propagation and its irregularities. Most of this data, also historically, is freely available. Digisondes are by far better candidates to look after scattering between heaven and earth. As far as I know, this trove had not been tapped. The Digisondes people are very accessible regarding information, software and advice. 73 Nils, DK8OK

  16. ALSM says:

    @Nils comments reminds me of the GPSMET and follow-on COSMIC data sets available for ionospheric research. Global TEC profiles. Thousands of papers have been written on the data produced. There might be something relevant buried in all that data and research.

  17. Victor Iannello says:

    @Nils, @ALSM: Do you think there is any chance that there is a historical data from a transmitter and receiver that were close enough to MH370 somewhere along its path such that the scatter was recorded?

  18. 370Location says:

    I must admit I’ve been captivated by the idea of utilizing quirks in signal propagation to track MH370 since it was first introduced here by Dr Rob Westphal. Sadly, the closer I’ve looked, the more unlikely the prospects.

    @Nils suggests other datasets and methods for validating aircraft scatter and characterizing long skips. Ionosondes, digisondes, and OTH radar always bring to mind noise sources splattering across ham spectrum. The mysterious Russian “Woodpecker” was a an OTH radar determined to be N of St Petersburg. “Grinders” were presumably broad VLF chirps by powerful ionosondes to measure the vertical ionospheric reflection, and possibly oblique refraction with dozens of transmitter sites.

    I’d be inclined to explore more of Nils’ methods for characterizing aircraft scatter, but I don’t see any that that could retroactively help with locating MH370.

    My mind goes to validating with more passive methods like TDOA detection of GPS synched receivers in KiwiSDR. Maybe even an experimental station that sends a digital blip and listens for its own circumglobal propagation by correlating with the original pattern. (Seems unlikely on HF due to D-Layer absorption during daylight hours. It would likely only catch path delays along the solar terminator, so might need the multi-antenna RDF method to determine direction).

    @ALSM suggests looking at research on occlusive reception of GPS/GNSS signal refraction over the horizon. That’s in the L band 1.5 GHz range, but reminds me of all the many services that would be impossible if the GDTAAA method of backward great circle propagation had any validity. It reminds me that WSPR may be seeing a combination of groundwave signals plus rarer ionospheric skips that both decay exponentially with one over distance squared.

    The KiwiSDR collaborative TDOA method of correlating GPS synced IQ data from multiple receivers to triangulate a transmitter is disrupted by even slight deviations from signals taking the shortest path between TX and RX, like variations in skip from optimal takeoff angle, or horizontal refraction from different terrain.

    Assuming that signals instead take the worst possible great circle signal path is at odds with Loran ship navigation, which has worked for decades before GPS. Military Over The Horizon coastal radar like JORN would be useless with multiple disruptions from aircraft flying on the opposite side of the globe.

    The recent comments on the GDTAAA blog by “Rob” Westphal shows him talking at cross-purposes to the method being used. He’s trying to validate WSPR aircraft scatter by picking up WSPR spots on short skip perpendicular to the baseline of TX-RX. That invalidates the GDTAAA assumption that aircraft scatter only works near great circle paths.

    Regardless, Happy Holidays to All! — Ed

  19. Victor Iannello says:

    @370Location said: The recent comments on the GDTAAA blog by “Rob” Westphal shows him talking at cross-purposes to the method being used.

    Agreed. @Mick Gilbert made the same point in a previous comment.

  20. … there is a trove of data from Digisondes, freely available. The surely cover historical data. I played with some data, but only having MUF in mind:
    If one likes to dig deeper, (s)he will be welcomed by one of those really nice and helpful guys at:
    The power of those digisondes is about 10dB above WSPR, but the GPS-driven, digital format together with smart algorithms ensure a considerable processing gain. Digisondes are developed to reveal (ionospheric) scatter. They may or may not be used to reveal aircraft scatter. This is more or less “clutter” when the main focus is to look after scattering above 50km. As far as I know, there is also existing “raw data”.
    I am convinced that OTH data (especially the Aussie’s) is perfect to answer more questions for many reasons. Undoubtedly, those data must have been inspected by the professionals. Alas, I read nothing about any results. If any information is searched for by “Aircraft scattering at HF signals”, for this region the Aussie’s radar must be the very first stop. They have the power, the waveform, are GPS driven and designed to discover just what we want to see: aircraft scatter until FL0.
    73 Nils, DK8OK

  21. Victor Iannello says:

    @Nils Schiffhauer: Perhaps @Sid Bennett can weigh in, as he has experience in this area.

  22. ALSM says:

    Nils: I know several people, including IG founder Duncan Steel, have looked into the possibility that the JORN OTHR observed MH370, but ultimately determined it was not observed because it was not operating at that time. Others here may recall more details. It has certainly been discussed.

  23. Andrew says:


    Some time ago the Australian Defence Force had a website that published FAQs about JORN. I can’t find it now, but I recall there was a question about MH370 that had been raised many times. The website stated that JORN was not operating the night MH370 disappeared. The reason given was that JORN was not resourced or tasked to operate 24/7 at that time, because the threat environment was benign.

  24. David says:

    @Andrew. Yes, I quoted from the RAAF site of the time, “Based on the time of day that MH370 disappeared, and in the context of peacetime tasking, JORN was not operational at the time of the aircraft’s disappearance. Given range from individual OTHRs, the ionospheric conditions and a lack of information on MH370’s possible flight path towards Australia, it is unlikely that MH370 would have been detected if the system had been operational.”

    I infer that there were unfavourable ionospheric conditions, at least for JORN purposes.

  25. Barry Carlson says:

    @Andrew, ALSM;

    It seems that the ADF haven’t shelved the JORN system; in fact they are investing mega dollars in updating the whole system with BAE Systems being the prime contractor.

    If you delve through the data on the above site, you’ll find reference to RAAF Base “Edinburgh” – north of Adelaide, as being the Battle Space operations center. The main physical hardware, i.e. the antenna arrays located in Queensland, Northern Territory and Western Australia, is to be updated.

  26. 370Location says:


    Math check, please.

    GDTAAA is using paths as short as 1000 km.

    Maidenhead grid error at each end is up to 5 km, so +/- 10 km over 1000 km or 1/100 of the distance.

    For the projected tripwire great circle, the error at the antipode of the path should be the mirrored +/- 10 km.

    At worst case 90 degrees around the globe (10,000 km), is the max tripwire error magnified to 1/100 of Earth radius (6400 km), or +/- 64 km?

  27. Mick Gilbert says:


    Given the range of likely flight paths, MH370 would have been well out towards the western edge of the coverage from Laverton just as the solar terminator was approaching that area. My understanding is that the night-to-day and day-to-night transitions are problematic for over-the-horizon radar. I recall, perhaps incorrectly, that there is frequency shift required to optimise performance when moving from night to day and back again. That’s possibly the “ionospheric conditions” they are referring to.


    That FAQ has definitely been removed or amended, hasn’t it?

  28. Mick Gilbert says:


    G’day Ed,

    I can recall looking at the inaccuracy problem that potentially arises from using just the centre of a Maidenhead Grid rather than the actual antenna location to project paths. As you’re no doubt aware, grid width varies with latitude so the potential error for the actual antenna position ranges from around ±3 kilometres up to around ±5 kilometres.

    I’m pretty sure that when I tried some practical examples that, because you’re working with great circle paths joining two points, the error doesn’t double (ie with two actual locations displaced by the maximum error in each grid, the offset from the midpoint to midpoint path is not the sum of the errors).

    In fact, if you take the maximum error in one grid as the upper left corner of the grid and use the lower right corner for the maximum error in the other, there is no error from the grid midpoint to midpoint path at the halfway mark. The in-error path and the midpoint to midpoint path intersect at the halfway mark. Geometry, I presume.

    All that said, it is a gross misrepresentation to be drawing those razor sharp (roughly 1 kilometre wide) path lines on the GDTAAA maps. The intersection of two paths should be shown as a 25 km² box. And that’s just to accurately represent the known Maidenhead Grid error.

  29. Victor Iannello says:

    @Mick Gilbert: Active hams query the database to determine the precise location of stations. It doesn’t appear there was any attempt to do this. Not that it really matters, because you would just more precisely get a wrong answer.

  30. 370Location says:

    @Mick Gilbert:

    Agreed that for short WSPR paths, opposite errors would cancel at the midpoint, but nearest the stations it should be 10 km. Both errors in the same direction would max at 5 km off the path.

    However, we are dealing with claims of a great circle tripwire that extends far beyond the defining short path endpoints.

    Imagine a TX maidenhead location on the equator at the prime meridian. The actual station could be 5 km south. Now place the RX maidenhead 1000 km away on the equator, which might be 5 km north. The slope is about 0.58 degrees, and the error along the great circle tripwire (a slice through the center of the globe) increases toward +/- 90 degrees along the equator, then back to 10 km at the antipode of the transmitter.

    On average, displacement errors will be smaller, but I’m looking to quantify the peak error that needs to be accounted for, which determines the average number of planes that might be confounding a purported result.

    @VictorI is of course correct that that both actual station locations could be found for a particular path, leaving only the propagation errors that add to the uncertainty.

  31. Victor Iannello says:

    Merry Christmas, everybody!

  32. Mick Gilbert says:

    Merry Christmas, Victor. Merry Christmas all.

  33. Don Thompson says:

    Best wishes for a relaxing Christmas to all!

  34. CanisMagnusRufus says:

    Merry Christmas to our gracious host and to everybody else.

  35. 370Location says:

    Merry Christmas! With sincere wishes for Peace on Earth, and goodwill toward all.

    Plus, hopes that inquiring young minds tracking Santa on will be drawn to critical thinking and STEM. 😉

    — Ed

  36. David says:

    @Mick Gilbert. You make a fair point re the night/day propagation transition.

  37. Andrew says:

    @Mick Gilbert

    RE: “That FAQ has definitely been removed or amended, hasn’t it?”

    I think so. I tried to find it earlier this year and was unsuccessful. I tried again a few days ago – same result.

  38. George Tilton says:


    “That FAQ has definitely been removed or amended, hasn’t it?”

    Is this it?

  39. sk999 says:

    JORN Fact Sheet / FAQ, as of May 27, 2015:

    “Based on the time of day that MH370 disappeared, and in the context of peacetime tasking, JORN was not operational at the time of the aircraft’s disappearance.”

    The fact sheet / FAQ would appear to be a document that evolves with time. The version referenced by George Tilton states, “JORN is currently undergoing a capability upgrade under JP2025 Phase 5.” The version of the FAQ that I cite states, “… future upgrades are planned under Project Air 2025 Phase 6.”

    My interpretation based on reading tea leaves: JORN is a system that seeks to justify its existence. Its “bang for the buck” seems to be prettly how. However, its proponents seem to be doing a good job. At least for now.

  40. Andrew says:

    @George Tilton

    That might be an earlier version of the JORN FAQ. The link in @sk999’s comment is an archived version with the question about MH370. The current JORN page on the website does not have an FAQ section:

    The Australian Defence Science & Technology Group that developed JORN also has a page on its website, that states JORN “provides a 24-hour military surveillance”. I don’t know if that’s accurate today; it doesn’t seem to have been the case in 2014:

    The Phase 6 upgrade commenced in 2018 and was expected to take 10 years to complete:

  41. Mick Gilbert says:


    G’day Ed, I see what you are getting at now. You’re looking at the long path.

    I’m sure that there’s some fancy book learned way of tackling that problem but for a simple practical approach you could look at plotting the following in SkyVector. Start, per your posited example on the meridian and 5 km south of the equator, at 000242S0000000W. 1,000 kilometres east of that is 000242N0085855E, 5km north of the equator. Assume that those are your two actual antenna, representing worst case errors from the centre of their respective Maidenhead Grid locations.

    If you then plot the great circle route to the antipodes for both of those (000242N1800000W and 000242S1710105W), that should give you the long path route between the two notional stations.

    The furtherest displacement from the path connecting the Maidenhead Grid points (the equator) is as much as 63.5 kilometres.

    That error needs to be weighed against the fact that that +5 kilometres and -5 kilometres differences between the Maidenhead Grid centre points and the actual antennae involved is the absolute maximum. Errors in the order of say ±2.5 kilometres would be be more realistic I think.

  42. Mick Gilbert says:


    Yes, I had the same experience.

    @George Tilton

    Thanks for having a scrounge around for it.


    Thanks Steve. That’s the version in question.

    Regards JORN not delivering bang for bucks, apart from an Audit Office and a Parliamentary Joint Committee report, both in the late 1990s, that were critical of the project and budget management aspects, there’s not been much in the way of criticism. The RAAF had it expanded from the initial proof-of-concept project to a fully integrated three array system; that would be unusual for something that wasn’t delivering.

  43. George G says:


    Re your request for “Math check, please”

    Some time ago I started to determine the uncertainties which might be attributable to “Maidenhead grid” approximations. This went to starting to considering “extreme” corner to corner effects, etc. I even intended to adopt a statistical or “risk” approach. The “worst errors” are actually between close, even adjacent, grid sectors. As the distance between Tx and Rx become greater then the significance of the effect becomes less, and less, if one were to be considering the intersection of paths between two (or more) Tx-Rx pairs.

    After some scribbles I concluded that an investigator would search out the actual (real) locations of the Tx and Rx for any “candidate” pairs, so the matter became of little interest.

    @Victor has already touched on this.

  44. George G says:


    “number of planes that might be confounding a purported result”

    Your answer of December 24, 2021 at 11:22 am to @Mick Gilbert, of course acknowledged that actual Tx Rx locations can be found, thus removing that uncertainty in the final analysis.
    But, your “number of planes that might be confounding a purported result” remains a significant task to discriminate between disruptions to the radio waves caused by the subject aircraft (being an aircraft of interest) and the many other possible causes.
    You may or may not have noticed that I broached this subject “elsewhere” some time ago where I could not tell if “other planes” being eliminated as cause of a disruption (my choice of terminology) were only in the vicinity of the suspect location of the aircraft of interest, OR if they (the eliminated planes) included ALL aircraft along the relevant (or candidate) radio path. This I considered of significant importance as the vicinity of a large number, perhaps a majority (?), of Tx and/or Rx will be in the vicinity, or areas, of fairly high population of aircraft in flight.
    AND, if a (WSPR or otherwise) radio transmitter or receiver IS in the vicinity, or area, of a high number of aircraft movements THEN the possibility increases for the radio receptions to affected by those aircraft movements. Hence your interest in the “number of planes that might be confounding a purported result”.
    Also, “elsewhere” I introduced the subject of thunderstorms and fires (particularly large fires) as being potential sources of disruptions to radio waves. That was dismissed as a serious concern. In my opinion it is (or they are) just another necessary consideration.

    Separately, but not really so, the effect of an aircraft “near” a transmitter, or even a receiver, is clearly magnified inversely to the distance between the aircraft and the transmitter (or receiver). I am not sure if this is clearly being taken into account in some instances, or quarters.

    As Dr Robert Westphal has clearly shown, and has been witnessed before, a radio transmission can be diverted by the passage of an aircraft through a radio beam, as I wish to call the set of radio waves impinging upon an aircraft, in such significant number of waves as to arrive at a receiver (regardless of the necessary path or paths to get there) at a strength to be recognised and thus “received” by a receiver. In some cases this reception may be considerably stronger than competing reception via a more “direct” path.
    Whether, or not, the historical “secondary” data stored in “” has sufficient information to utilise this effect to advantage has yet to be proven by example.
    It follows that your task of finding the “number of planes that might be confounding a purported result” becomes a gargantuan task. Not only those in “direct” path, but perhaps even more importantly those NOT in “direct” path, may come into play.
    This, of course, means that if someone had ALL the data available concerning aircraft in flight, and radio receptions and massive computing power (and were able to “get their head around” it all) …….

  45. Victor Iannello says:

    @George G said: It follows that your task of finding the “number of planes that might be confounding a purported result” becomes a gargantuan task.

    To be consistent and to select “anomalous” spots without bias, yes, a very difficult task. But, considering it is nearly impossible that a low power HF WSPR transmission interacted with an aircraft over long distances in a detectable way that was archived, it is a futile task if the objective is obtaining a useful result.

    Those that continue to promote using WSPR data to find MH370 are providing an unintended beacon of a different nature.

  46. 370Location says:


    @Mick Gilbert,
    Thanks for the reality check on the max path error math. I agree on the smaller values for short skips, but GDTAAA uses only a few of those, and they are near 10K km. The rest of the tripwires are all circumglobal long paths that would encompass many planes along the way. If the error range is from nil to +/- 64 km on the equatorial great circle, then halving it and adjusting for smaller errors at higher latitudes should give a good estimate. Say, +/- 25 km, with 2 planes for every 5 km, gives about 20 planes on average in the long skip virtual paths.

    @George G,
    Yes, the path accuracy can improved by digging up more accurate ham station QTH location, but that’s not what was done with GDTAAA to track MH370. I fully agree that there are many other possible sources of interference with skip propagation, which also include variations in the unknown RF gear. For any single tripwire, the unknowns are overwhelming. Using a statistical method over one day with a huge volume of WSPR and ADS-B plane position data, most of those transient effects should average out, leaving a measurable effect from 4K known planes flying near 3M known WSPR paths.

    @WSPR testing:

    Having already done the drift variation plot for tripwires with a negative result, I also have been looking at what evidence for aircraft scatter might be in the WSPR data. I of course focused on the actual path segments between stations rather than virtual tripwires. I’ve also been looking at wider doppler shifts rather than the limited 4 Hz drift within one spot. @sk999 showed the possibility of double spots from scatter on the same contact with weaker a doppler shifted spot matching the main carrier. @Don also made suggestions and we looked at averaged WSPR frequency by distance.

    I’ve taken that python code quite a but further. Averaging by ham band was problematic, because some bands have multiple WSPR areas, or at least hams working WSPR outside the usual narrow range. So, I’ve broken up the WSPR data into 1 KHz sub-bands, which works nicely the 0.2 KHz ranges.

    Many TX are cycling through the HF bands. It turns out that each TX can also be characterized by getting averages from all the receivers that got a spot from it. Once the mean TX frequencies are known, the same trick can be applied to get an averaged offset for each RX. This gives a fairly accurate base for looking to see if each spot has been doppler shifted.

    Of course stations are being manually shifted in frequency and there are other variables, but with large numbers those should again appear as noise.

    Here is a plot that again splits frequency shifts into pos and neg offset sample sets, and plots the average variation by distance. Reducing the bin size to 2 km has added some resolution, despite raising the minimum flight altitude to 20,000 ft:

    My speculation about the large shifts at long distances is similar to that for the previous WSPR drift value plots. As the region nearest the paths is most critical, here’s a zoom in:

    (That url was random from Google. Really.)

    A very small bump might be seen within 100 km of the paths, but it’s still down in the noise, and not anything that could be useful. The bumps do seem to come and go on smaller samples of different hours in the day.

    Thinking that the averaged data could be hiding an underlying pattern that gets canceled out, it seems that a histogram of each bin, especially those nearest the paths, might reveal doppler shift patterns:

    The brighter pixels have more occurrences of the sample values. A cluster around -10 Hz nearest the WSPR path might be expected, but is not seen. The image has been enhanced by first scaling by the mean values far more common nearest zero freq shift. An FFT removal of remaining horizontal bands gives a fairly flat background, which is then contrast expanded by using histeq image processing. The original 20 km binning and coarser frequency bins appeared to show a weak arc centered from 20-50 Hz around 100 km from the path. Using the current 2km resolution with finer frequency resolution has increased the noise somewhat, and the arc is no longer evident.

    Increasing the sample count by using a lower cutoff altitude could reduce the noise. Acquiring more than one day of ADS-B dataset would be the next step. 11 billion lat/lon distance calculations are a bit slow, even with a spherical globe. It takes about a half hour to crunch these plots with vectorized python code.

    Sadly, it’s another negative result for now. Any suggestions or speculation are appreciated.

    — Ed

  47. Victor Iannello says:

    @Ed Anderson said: Sadly, it’s another negative result for now. Any suggestions or speculation are appreciated.

    It’s a negative result, but it is also what we expect.

    Despite the long-winded, incoherent explanations that attempt to refute this post, the (S/N) calculations were made with the most generous of assumptions regarding propagation losses, radar cross section, incident angle, and noise floor. The calculations show that WSPR contacts can occur at long distances (no surprise since they are recorded in the database) but scatter of WSPR signals off an aircraft CANNOT be detected at long distances. The claim that forward scatter from MH370 was detected at 17:16 UTC between the Swiss transmitter (HB9CZF) and Australian receiver (VK1CH) is shown to be false as the strength of the scattered WSPR signal is orders of magnitude weaker than can be detected. The claim that an anomalous WSPR signal between the Swiss and Australian stations was recorded at 17:16 UTC has also been proven to be false as the deviation of signal strength, frequency, and frequency drift are all within the limits of the variation in values experienced within a 16-hour window, that deviation caused by the dynamic character of the ionosphere.

    So why do people continue to promote a theory that can easily be proven false by anybody skilled in the art? This is not the first time we’ve seen this pattern of behavior regarding MH370 claims, which includes presentation of straw man arguments and obfuscation of facts to confuse those without the basic technical background to recognize the incoherence.

    I am proud of the contributors of this blog. I am not aware of any other place where a rational discussion of technical matters related to MH370 occurs.

  48. 370Location says:


    You are indeed curating a blog that is nearly unique in promoting serious open discussion of MH370 technical issues. Thank you for allowing my input.

    Those tactics you mention are prominent among FaceBook forums, where I presume most experts have been driven away or left in frustration. The most frequent posters there admittedly have little technical background, so it appears that instead of debate they use the argumentative skills that have worked for them in the past.

    I have yet to see a technical dispute anywhere of your WSPR report, and I don’t expect there will be any.

    OTOH, the GDTAAA lists 31 specific and wide ranging claims for the method, which is not unlike those made for a patent filing to cover future invention. So many outrageous claims also makes it nearly impossible for anyone to summarize the many problems without taking time for a full disseration. That makes peer review also less likely.


    Out of curiosity, I tried looking at doppler by distance from all planes aloft regardless of altitude. Small planes would not be expected to influence HF radio signals, and average to nil. To obtain more samples, I also expanded down to the 3.5 MHz band which would include much more groundwave propagation. The result is rather interesting:

    This plot does show a sharp bump that peaks with planes about 23 km from WSPR short skip segments, and another broader effect at about 320 km.

    I implemented a change in the histogram that should not affect the plot above. Doppler shifts appear to be proportional to frequency, which would be widely smearing the multiple bands vertically in the plot. So, the delta frequency shift is now divided by detected frequency, which should align the bands. This doesn’t boost the occurrence or amplitude of lower frequencies, but instead gives a unitless measure similar to Hz offset but scaled to match a 5 MHz carrier. The results are also a surprise:

    There are now various striations and clusters being revealed out of the noise. Most are not a strictly vertical line that’s uniform with distance, except for the sharp cluster at 320 km, which could represent skip or groundwave reflections at some favorable angle to the planes. It would be interesting to narrow the sample set based on TX-RX distance to see where it’s most prominent.

    An odd feature of the striations is that while they are several km wide (2 km pixels again), there is a dip in hits on the near side followed by a peak on the far side. It looks like an image enhancement artifact, but there is no spatial contast enhancement being applied to the data. I have no good explanation, but it would seem to be tied to where planes moved on successive spots related to their direction of flight. The sample set is huge, so they couldn’t be individual flights.

    The slight dip right over a WSPR path seems to match with @DrB’s assessment that there would be little doppler along the path except for vertical speed. The peak at 23 km might be accounted for by stations near busy approach/takeoff paths, since it was not seen on FL20 or above. I’m open to educated guesses about what the admittedly noisy features in the histogram plot mean in reality.

    I see this as a positive step toward understanding aircraft scatter, but absolutely not for validating the completely unrelated methods used in GDTAAA.

    For the hams in the group, here’s a plot of the WSPR frequencies used:

  49. Victor Iannello says:

    @370Location: Have you looked at Doppler shift versus distance from a WSPR station rather than distance from the short path between stations?

  50. Amble says:


    I do not understand some of the science of WSPR but was underwhelmed by the attempted refutation of your critique of the 17:16 UTC “sighting” of MH370. Your description of the refutation as “long-winded, incoherent” is spot on.

  51. Victor Iannello says:

    @Amble: Thank you for the comment. To paraphrase @Nils Schiffhauer: The science is understood. The social-psychology, less so, but that’s not the point of this blog.

  52. 370Location says:


    I could modify the code to make the plane distance axis be the lesser of the distance to either station, but it would ignore any info about the bath between them.

    I did try restricting the samples to only WSPR paths over 2500 km, which should be multihop skips. Most of the striated dhistogram features and clusters disappeared, and the averaged offset plot has a slow dip toward the short skip distance origin.

    BTW, these WSPR spot frequency analysis methods have not been a part of GDTAAA or the 31 claims. I place my work on them in the public domain so they cannot be included in any patent filings.

    — Ed Anderson

  53. Victor Iannello says:

    @370Location said: I could modify the code to make the plane distance axis be the lesser of the distance to either station, but it would ignore any info about the bath between them.

    Understood. But I think this analysis would also add to our understanding.

  54. Hi, all – proponents of the thesis that WSPR log data is suitable for tracking aircraft have promised us a paper dedicated to HF propagation for some time. Undoubtedly, this paper will come to the following results, if one sticks to the current state of science:
    * The changes in amplitude, Doppler shift, phase, and multipath caused by the dynamic ionosphere are large compared to the changes caused by aircraft scatter.
    * The individual causes of the signal changes can only be detected qualitatively, but not quantitatively (“drift” is not a – unique – proxy for Aircraft Doppler).
    * Since the respective current state of the ionosphere as by far the strongest “modulator” of the signal in the regions (!) of refraction are not known neither by location and frequency, nor by TEC or even the stratification, this cannot be extracted.
    * Even a 3D modeling with PropLab only reproduces the underlying statistical-empirical IRI model, but not the reality.
    * The small number of samples, their high integration time over 110 seconds and uncertainty about the technical quality of the transmitted signal make a robust statistical evaluation difficult.
    * The signals, which are already low without Aircraft Scatter, are increased in their totality by Aircraft Scatter below rather than above the safe detection limit.
    Furthermore, the denunciatory and non-technical-scientific argumentation of the defenders of the WSPR thesis does not exactly contribute to its credibility – of which, however, an actual technical-scientific argumentation must remain unaffected. Sine ira et studio.
    I have a good overview of the scientific literature on HF propagation, have made countless measurements of my own and have also published various papers on this subject.
    For epistemological reasons, the proof that something that may be possible in principle is not possible in reality cannot be given. If the black box should be found at the predicted place, this is at best a lucky coincidence, but is not connected with bent WSPR calculations.
    The procedure and the considerable PR hype of this “company of whiskers and windbags” damages the reputation of amateur radio as a serious scientific hobby. Quotations from BBC to NYT are no scientific proof of the thesis, but of the cleverly triggered wishful thinking of, tech-wise, lazy thinkers. It is a pity that Prof. Joe Taylor, K1JT, is not heard in this public discussion, but it is highly understandable.
    Yes, I would also like to have a different result. But this is not possible on the basis of the data.
    Eagerly awaiting the announced paper: Nils, DK8OK

  55. Mick Gilbert says:

    @George G

    George, regards the potential error arising from using the latitude and longitude for the relevant Maidenhead Grids in lieu of the actual transmitter and receiver antenna locations, you wrote,

    … I concluded that an investigator would search out the actual (real) locations of the Tx and Rx for any “candidate” pairs, …‘.

    Unfortunately, your conclusion does not appear to be supported by anything we’ve seen in the author’s work to date. None of the papers presented to date show anything other than the centre of the respective six character Maidenhead Grids being used for ray tracing.

    Moreover, while many radio amateurs post their actual locations in latitude and longitude on the likes of, some do not. And there are examples of stations being used by the author of Grid Determination Troubles Absolutely Affect Accuracy where the actual antenna location is not listed in the database (or the odd case where the listed location does not match the Maidenhead Grid).

    You also wrote,

    The “worst errors” are actually between close, even adjacent, grid sectors. As the distance between Tx and Rx become greater then the significance of the effect becomes less, and less, if one were to be considering the intersection of paths between two (or more) Tx-Rx pairs.

    Quite correct. The shorter the short path between the two stations, the greater the potential error at the target location on the putative long path. But there’s the rub. The author routinely uses the supposed long path of relatively short short paths for his ‘position indicators’. In his (not so) “blind test” involving QF6036 there were nine ‘position indicators’ utilising a total of 19 WSPR spots. Out of the 19 connections used, the short paths for ten were less than 2,000 kilometres and six of those were less than 1,500 kilometres. For the 05:02 UTC example, both connections used to determine the ‘position indicator’ were less than 1,100 kilometres.

    I have looked at a couple of connections used in the (not so) “blind test” where the Actual v Maidenhead Grid discrepancy produces errors of around 15 kilometres at the target zone. And in case you were wondering, no, those errors don’t fix the problem of the author being unable to determine the actual position of the target aircraft in at the very least seven of the nine ‘position indicator’ examples detailed in that paper.

    I’ll write more on this when I get the chance.

    You also noted that,

    ‘… the effect of an aircraft “near” a transmitter, or even a receiver, is clearly magnified inversely to the distance between the aircraft and the transmitter (or receiver). I am not sure if this is clearly being taken into account in some instances, or quarters.

    Well, one of the “quarters” where that particular issue has not been taken into account is the GDTAAA methodology. Clearly many of the radio amateurs didn’t get the memo not to set up their equipment near major airports! In looking at some of the (not so) “blind test” links I found a number of cases where, at the time of the recorded WSPR spot, their was local aircraft traffic proximal to either the transmitter, the receiver or sometimes both.

    I’ll write further on this also.

  56. 370Location says:


    I’ve run a WSPR doppler plot as you suggest where the X axis is the shorter distance from Tx or Rx to each plane aloft:

    While there is a steep drop in frequency shift near a Tx or Rx, the mean is unreliable because the number of sample planes shrinks to zero along with the radius around the stations. The distogram has a similar problem:

    The dark section near the zero origin is likely an artifact of the steep drop in samples compared to the
    already low counts beyond 75 pseudo-Hz on the plot. Also note I’m using an FFT to remove orthogonal banding, along with subtraction of smoothed row and column data. An entropy plot might reveal more, but it’s very noisy.

    I also tried reducing the dataset by spot path (not bath) under 500 km to see just single skips and groundwave. The mean plot looks similar to the longer path plot, but the distogram has a unique feature:

    There appears to be a diagonal below 50 km that strongest on positive doppler, but may continue to negative values at even shorter distances.

    @Nils and @Mick: I agree with all the points you both made. Perhaps it’s not best to be iteratively releasing data plots like this in an open forum. That was part of the problem with comments on the GDTAAA blog getting dumped into the media as daily breakthroughs before any of it could be vetted.

  57. Sid Bennett says:


    Forgive my silence please. Best wishes of the season to all of you.
    I have been distracted by a project to bring electric vehicle charging capability to our condominium.

    I appreciate your work to provide an analytical structure to refute the claim that WSPR can be of any value in the search for MH370. My work in the field goes back to the mid ’60s and continued for almost 15 years. I have watched the real-time displays of OTH-B for countless hours at that time and saw many ionospheric effects (amongst others).

    My technical papers have long since gone into the government shredder.

    The Woodpecker site is actually in the Chernobyl radiation exclusion zone, but can be visited (carefully). The equipment in the buildings is gone, and some of the the antenna array has been salvaged for scrap.

    I regret that WSPR has become such a diversion.

  58. Victor Iannello says:

    @Sid Bennett: Yes, it is an unfortunate diversion. That said, I think we have fulfilled our obligation for exposing the truth.

  59. Mick Gilbert says:

    @Victor Ianello
    @Sid Bennett

    Speaking of diversions, unfortunate or otherwise, there’s another comic book out on the Guessing, Doodling and Tracing channel. A bumper end-of-year edition.

    While largely bereft of much in the way of technical detail there was this,

    When an aircraft changes from flying over land to flying over sea, there is often a change of wind. This can cause turbulence which in turn changes the radar cross section (RCS) aspect of the aircraft making it easier to detect with radio signals such as WSPRnet links.


    And moving on, there were a limited number of WSPR spots discussed in the context of them each being a “candidate detection of MH370“. One of those discussed was the 17:16 UTC WSPR spot transmitted by HB9CZF in Switzerland and received by VK1CH in Australia. That particular spot, over the distance of 16,530 kilometres, was meant to have been discerned by the methodology as an “SNR and Drift Anomaly”, purportedly an “SNR Scattering” (whatever that might be, the term is not defined).

    Being branded an “anomaly” one would expect that the SNR, Drift or Frequency data for that particular spot would be, well, anomalous. Imagine my astonished surprise when I looked at the data for 24 hours either side of the nominated 17:16 UTC spot and found nothing of the sort amongst the 69 connections that were recorded during that 48 hour period.

    The SNR, Drift and Frequency values for the “anomaly” were -20, -1 and 14097079 respectively.

    The mean SNR for the 69 spots was … – 20.

    The mode for Drift and Frequency were -1 and 14097079 respectively.

    The data for the 69 spots is graphed here –

    The “candidate detection” is highlighted on each graph by the red/orange diamond. It surely says something that I needed to do that highlighting because the actual results for this purported anomaly were entirely unremarkable. The results, either individually or in combination, could not be less anomalous if you tried.

    So there you go … it’s bullshit!

  60. Victor Iannello says:

    @Mick Gilbert: As you recall, the post above was meant to study the claim about the detection of MH370 at 17:16 UTC. The SNR, drift, and frequency plots (the final three figures) are essentially the same as you presented in your link.

    You would think that if somebody made these claims about MH370 detection using WSPR data, they would choose to demonstrate it with a case that did not fail miserably.

    Anybody with the relevant technical background is laughing at this saga. Or completely ignoring it.

  61. TBill says:

    Good you picked up that point, otherwise I am not seeing much new in the new report. I was expecting more BTO/BFO analysis at each Arc as well as 18:25-18:28 showing the alternate fit to the generally accepted N571 offset maneuver, and at Arc7. If we have FE just past Arc6 at 00:12 then there is quite a bit of gliding time (7 minutes) to get to Arc7 at which point apparently the active pilot does what with the APU? Turn APU on at 00:17 to restart SATCOMs and happens to record an intentional dive at 00:19? But I am not sure if there is enough altitude and speed remaining for the flutter explanation of right flaperon trailing edge damage and separation.

  62. Victor Iannello says:

    Here is an interesting summary of an event in which an Emirates B777 taking off from Dubai rotated late and remained at low altitude before resuming a normal climb. Some believe this is a case of over reliance on automation, and in particular the Flight Director, which gave erroneous direction due to an incorrect altitude set in the MCP.

  63. Victor Iannello says:

    @George G: And you never got a coherent response to that analysis.

  64. Mick Gilbert says:

    @George G

    Thanks George, I can’t recall having seen that paper of yours before. Pretty well sums it up.

  65. Mick Gilbert says:

    @Victor Iannello

    You opined, “You would think that if somebody made these claims about MH370 detection using WSPR data, they would choose to demonstrate it with a case that did not fail miserably.

    I agree.

    I would add, however, that two of the other three examples of “candidate detections”, the ones at 17:02 UTC and 17:08 UTC, are potentially even worse. Best of a bad lot, springs to mind.

  66. Victor Iannello says:

    More complete hogwash from Geoffrey Thomas. Some of his claims:

    1. It’s unfortunate that there are detractors to the WSPR tracking theory. (Why unfortunate? Informed questioning should be encouraged by journalists.)

    2. All questions have been answered in detail. (What we have are long-winded answers that don’t answer basic questions, and claims that defy the known math and physics.)

    3. There is support from highly credentialed individuals, such as the former head of engineering at Google. (I’ve been in contact with Alan Eustace. He told me very clearly that he has NO background in this area, and makes no claims about the validity, leaving that to others.)

    4. The theory has been proven with blind tests. (The Qantas test and the MH370 position at 17:16 UTC both were failures, despite claims to the contrary.)

  67. TBill says:

    Re: Emirates B777 taking off from Dubai
    It was a teaching moment for me, I always turn on Flight Director in the sim but I never knew what it did. Now I know it gives the magenta cross hairs on the screen, which gives the pilot guidance on suggested trajectory. I can assure you I never over-rely on that guidance.

  68. Don Thompson says:

    UAE 231

    The incident appears to have caught the interest of aviation bloggers. It’s difficult to make an adequate analysis of the incident from FR24 and other trackers. FR24’s archive displays the usual issue where playback data has been interpolated/smoothed for archive. I suspect there’s an issue with FR24’s archive record: the record’s altitude field is not corrected for prevailing field baro pressure. Unfortunately, ADSBX only picks up the departure at 23:11:31Z when the aircraft has attained 1750ft, so after the incident.

    ‘Green Dot’ makes a number of errors in his narrative: A6-EQI had arrived at OMBD, ex-Zurich/LSZH some 20hrs prior to the UAE231 service, not two days prior. He then states “the aircraft was grounded for four days” following the return service Dulles/KIAD to Dubai/OMDB: incorrect, its next sector was Dubai-Brussels, only 46 hours later.

    The MCP target altitude setting appears to be a focus of these reports, perhaps the Barometric Reference on the EFIS Control Panel was the source of the error. Certainly, the aircraft did not initially begin a normal climb while it appears the autothrottle had commanded take-off thrust resulting in g/s exceeding 250kts.

  69. Andrew says:

    RE: EK231

    Although we don’t know the full details of this incident and much of the discussion is speculation, the video @Victor posted raises a number of serious issues about pilot training, automation dependency and crew coordination. These issues have been with us a long time and the degradation of pilots’ manual flying skills has been the subject of much debate in recent years. The pandemic has certainly not helped matters, with many pilots around the world grounded. Many of those who are still flying are not getting the practice they need to remain fully proficient.

    Much of the speculation about this incident hinges on Emirates’ release of a company NOTAM shortly after the event. That NOTAM directs pilots to refrain from setting the MCP altitude window to the airport elevation after landing/shutdown. It seems to suggest that such a practice might have been a factor in the EK231 incident. Unfortunately, some pilots have the habit of ‘tidying things up’ for the next crew by selecting all the MCP settings (IAS/HDG/ALT) to ‘zero’; a practice that is not required by the FCOM and can have unintended, serious consequences.

  70. Andrew says:

    RE: “More complete hogwash from Geoffrey Thomas…”

    Has anyone here contacted Geoffrey Thomas to refute these claims?

  71. Victor Iannello says:

    @Andrew: For me, it was by email and Twitter. It’s no use. He’s very dug in.

  72. George Tilton says:


    According to “Geoffrey Thomas is Channel 7’s Sunrise Breakfast show’s aviation commentator and is the “go to person” in Australia and New Zealand for any aviation event.”

    I guess that would make him Australia’s version of Larry Vance or Jeff Wise?

    I do not trust self-promoting journalists…

  73. Andrew says:


    Fair enough!

  74. TBill says:

    Re: EK231
    Regarding the “tidying things up” since that practice is not so good for B777, does that practice originate from habit from flying other aircraft models?

  75. Brian Anderson says:

    Geoffrey Thomas is not a recognised “go to” in NZ on aviation issues. Virtually unheard of here, except we do get occasional news segments fro Australian channels, so he might appear there, infrequently.

  76. Victor Iannello says:

    Here’s a better description of the EK231 event from Jon Ostrower, although he doesn’t seem to understand that once the MCP altitude is set to the current altitude at ANY altitude, the autopilot enters ALT HLD mode and is not responsive to changes in MCP altitude settings. That’s not a quirk. It’s fundamental to the functionality of ALT HLD mode.

    [Thinking about this more, perhaps it’s a bit more complicated because the A/P might have been in VNAV mode, and the climb probably required an “altitude intervention” by pressing the ALT button.

    That said, this is normal operation, not a “quirk”.]

  77. Andrew says:


    RE: “…does that practice originate from habit from flying other aircraft models?”

    I don’t think so. It’s not SOP on other Boeing or Airbus types that I’ve flown. This type of practice sometimes creeps in when a senior pilot decides that something should be done a certain way, even though it’s not written in the manuals. Before you know it, others start doing the same thing and it unofficially becomes ‘SOP’ for some pilots. Airline management and check & training pilots spend a lot of their time trying to stamp out such practices.

  78. Victor Iannello says:

    Re: EK231

    I understand why it might not be best practice to set the altitude setpoint to zero after a flight, but if the next crew did not change that value, it means the ATC altitude clearance was not entered before takeoff. That seems like a much worse offense.

    And I’d say following the Flight Director when the guidance was not consistent with the takeoff rotation speed and the expected climb pitch is even worse.

  79. TBill says:

    “practice sometimes creeps in when a senior pilot decides that something should be done”

    I suppose that is common tendency in many technical workplaces, a fellow engineer conjures up a “recommended” technique to do something. That works fine if (1) the engineer’s method is correct, or (2) it may not be correct, but for many situations it does not matter too much.

  80. Andrew says:


    Absolutely. There’s a lot we don’t know, but if this event played out the way it looks, there were some serious procedural errors and a breakdown of basic airmanship. Jon Ostrower’s article claims the ADS-B data shows the MCP altitude was selected to 4,000 ft, but of course we don’t know when that occurred. The initial clearance altitude might have been selected during the normal pre-flight flow, after the FD switches were selected ON. However, that doesn’t explain why none of the pilots noticed the aberrant FD pitch mode and associated guidance, which are also part of the required checks. It also does not explain why the flying pilot (apparently) followed the incorrect FD pitch guidance after take-off, if that’s what occurred.

    This morning’s Sydney Morning Herald has an interesting article about the problems Qantas found after its pilots returned to work after long periods without flying:
    Qantas pilots making errors after long periods without flying

  81. Andrew says:


    In the multi-crew airline world, it’s also important that pilots follow standardised procedures to ensure there are no ‘surprises’ when one pilot does something the other pilot isn’t expecting. If someone has a good idea for doing something a certain way, it needs to be discussed by both management and the check & training people to ensure any risks are identified and managed. If accepted, the procedure then needs to be promulgated to all pilots, with appropriate training where necessary. That process often requires collaboration with the aircraft manufacturer and sometimes the national aviation regulator, to ensure there are no technical objections to the new or revised procedure.

  82. Barry Carlson says:

    @Brian Anderson wrote;

    “Geoffrey Thomas is not a recognised “go to” in NZ on aviation issues.”

    A couple of days ago I came across a CNN article –

    World’s safest airline: Air New Zealand takes first place on the annual list of the safest airlines around the globe from

    I haven’t seen any mention in the NZ press, and Air NZ don’t appear keen to “beat their drums” over the CNN / GT sourced article.

  83. Victor Iannello says:

    @Barry Carlson: That’s interesting.

  84. Victor Iannello says:

    For your entertainment:

  85. TBill says:

    That is quite entertaining. First of all, as an engineer, I completely do not understand journalists desire to shot down the good facts we have. This one aspect about MH370 for which I cannot grasp the explanation.

    But this speech really went other worldly when we found out FdC and JJWise are WSPR skeptics along with IG.

  86. DrB says:


    You are correct. It’s quite amusing when someone quotes Jeff Wise as the credible source to dismiss the WSPR aircraft tracking theory. It also establishes the extent of her journalistic and research capabilities.

  87. Victor Iannello says:

    @DrB, @TBill: I’d say it’s also a sad commentary on journalism today that her “facts” were not challenged by anybody in the room. Either they were overly polite, or the skeptics skipped the talk.

  88. Hi, all – with the discussion still humming, I pressed a Reset button for the average radio amateur and put the most important aspects into a dialogue-like Q&A:
    Should make an easy reading.
    It might help (or not) in some discussions …
    73 Nils, DK8OK

  89. Victor Iannello says:

    @Nils: At this point, the facts are on the table and discoverable by anybody that cares to look. The physics simply do not allow what is claimed. There is little more we can do.

    On a positive note, the area that WSPR proponents want to search is in the general vicinity of where most of us believe the plane is. Most people are not able to understand the nuance of somebody that proposes the correct general area for all the wrong reasons.

  90. George G says:

    @David, Thank you.

    An internet search for “KNKT” was unsuccessful, but the Interim Statement can be accessed via a search for:

  91. TBill says:

    Interesting the Himawari weather satellite captured the Tonga volcano down under. No such luck for MH370, but maybe we need to ask for an animation.

  92. Mick Gilbert says:


    Bill, you can see the islands of Fiji and Vanua Levu in the top left of some of those satellite images.

    By my reckoning there are at least two large commercial aircraft in that shot. An American Airlines B787 is just to the west of and about to overfly Vanua Levu and a Qantas A330 is just to the north of Vanua Levu heading north east. I doubt that there’s sufficient resolution available to discern either aircraft.

  93. TBill says:

    OK…if there were contrails or a splash in the water, perhaps we could see. The other aspect is the sunlight terminator gives a feeling for visibility in darkness vs. day.

  94. CanisMagnusRufus says:

    Report by the NoK of passengers on board UIA flight PS752 shot down over Tehran in Jan 2020.

    Strong evidence indicates this particular aircraft was deliberately targeted by the IRGC.
    Why? The authors speculate the aircraft was a human shield to prevent further escalation of conflict between US and Iran.

    But why this aircraft and not another?
    Perhaps the ownership of UIA may have something to do with it?

    This may explain reluctance of RCMP to acknowledge that PS752 was deliberately targeted in its own report, or their reluctance to cooperate with Ukraine’s investigation.

  95. Victor Iannello says:

    @CanisMR: I haven’t studied the report long enough to determine if the claims are solid, but nonetheless, the NOK have assembled an impressive body of work.

  96. CanisMagnusRufus says:

    Diane Francis of the Atlantic Council wrote this about the incident:
    There were no Americans on board, but Boeing is a big fat American target. Besides that, the Ukrainian airline is partially owned by Ihor Kolomoisky, a prominent Ukrainian oligarch, with deep ties and citizenship to Iran’s other “Great Satan,” Israel.

    According to the report by the NoK, the IRGC was inquiring from the passengers if any held US passports, and removed some passengers from the plane prior to departure.

  97. CanisMagnusRufus says:

    ICAO has released first report into the diversion of Ryanair 4978.
    “ The ICAO’s team said Belarusian authorities claimed to have received two identical emails from the militant group Hamas alerting them to a bomb…

    But the ICAO never saw the first message as it was received by Belarus in its original formatting. It was only able to verify the existence of both emails as other airports in nearby countries received them as well.

    “The receipt of the first email is crucial to explain the basis for the communication of the bomb threat,” the ICAO report said, as Belarus said it got the first note at 9:25 a.m. GMT, and started communicating with the flight crew five minutes later. The second arrived at 9:56 a.m.

    Belarusian authorities said the original emails were deleted because of their data retention policy.”

  98. TBill says:

    Pretty good explainer: FlightRadar24’s AvTalk podcast about the USA’s 5G fiasco this week, where the airline industry was objecting to the 5G rollout due to potential interference with aircraft. The B777 was part of story because Boeing initially said they would by impacted, but apparently fairly quickly reversed course.

  99. CanisMagnusRufus says:

    BBC is reporting that liberal US Supreme Court justice Stephen Breyer is to retire.
    The top contender for his replacement may be Judge KBJ, who dismissed the lawsuit brought by the NoK of MH370.

    Meanwhile, FdC’s book has been translated auf deutsch.
    A sympathetic review (behind a paywall) in Die Welt.

    Based on the FCCHK video, it’s remarkable that FdC has pretty much doubled down on her thesis.

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