Finding the MH370 with WSPR? (#667)

[Music] hello auggies worldwide and welcome to another ask day video today's topic is one that was requested by several hams and it has to do with the mysterious malaysian airlines mh 370 flight disappearance it was a large aircraft i believe a boeing aircraft left from malaysia on its way to um china and it was tracked as taking off for the indian ocean and then it's disappeared it's been aviation's greatest mystery and since the disappearance of amelia earhart now um i want to talk a little bit about this and kind of some technical detail so you get some ideas that are going on there was a 60 minutes episode on australian tv not too far back where some ham radio operator from great britain announced that he had used amateur radio techniques to locate where it must have gone down the him it's clear from what he was talking about that it was whisper which is weak signal propagation reporter and he was using logged data from the day of the disappearance and he had constructed a flight path from the data it's very controversial because there are those who say that you can't do that and those who say that you can so i thought what i would do is just talk a little bit about it now do i believe this guy or not well i believe he did something whether he was tracking the flight is another story and the inventor of whisper has been on record as saying he doesn't think whisper could be used for that so i want to talk a little bit about that here are the points i want to make first let's talk about whisper availability even in the area and then we'll talk about direct reception uh versus multipath reception and then we'll talk about doppler could doppler be used for this and some other investigations and joe taylor's thoughts on this uh which happened to be hearsay because i don't have a direct quote from joe but i'll let you decide whether it's the right i think it is now let me tell you my bias right up front i don't think that this could be done with with whisper it's uh whisper is not designed to track anything except the behavior of the ionosphere using uh its its weak signal propagation reporters what it is is propagation that it's reporting here is a picture of the airplane this is uh malaysia airlines and the flight number was mh370 okay this particular picture comes to us courtesy of laurent um herrera okay and it's not quite um public domain it's under creative commons 2.0 attribution so there i've had attributed that this is the same airplane taking off from charles de gaulle in paris okay so it's like i said a big airplane modern airplane uh equipped with modern avionics and should have done very well now let's talk a little bit about whisper joe taylor created a program called wsjtx and he's been updating it and updating and updating and updating it now there's a subset of that called whisper it's one of the modes that you can do ft8 is another one of the modes that you can do or jt 65. there is a dedicated program for whisper but it does the same thing as this so i just use this uh i took this this afternoon strictly recording i didn't do any transmissions strictly recording and you can see that in a two-minute period this transmits every two minutes it's important the transmission is two minutes long and then you receive for 18 minutes then you transmit for two minutes and you receive for 18 minutes and all of this is sent via internet to a website that i'll show you in a minute this is what the waterfall looks like this is in waterfall format if you go into the whisper program it's in this format uh with the waterfall going this way okay so it's the equivalent display and what you're seeing here is in a very narrow bandwidth okay this happens to be on 30 meters and it's going from 1.0 10 megahertz um 10.1 400 megahertz to 10 point i'm sorry 10.1 [Music] um let's see it's i'm looking at my radio it's 138.7 so there is a 200 hertz bandwidth so it's very narrow band and these are all the signals that are transmitting you can see the various strengths of the signals and then they are tabulated in another window which i'm looking for tabulated in this window okay now this data right here is sent via internet to whispernet.org it's w s p r n e t dot or g and let me just check that it's an o r g okay sorry about that a little delay there it's whispernet.org all of this information is sent there from the waterfall we don't send the waterfall we just send the decoded text let's take a look at what's in here okay the 22 white is utc which happens to be today it was about a half hour ago uh the signal strength compared to an arbitrary reference inside of the program is either this top one is quite strong it's 7 db above and then it can get extremely weak signals like this one minus 24 db below the threshold that it uses so get some very very weak signals look at dt here's the delta time from the sender's clock to the receiver's clock is in this case 0.1 seconds it the resolution on this is only 0.1 seconds you can't do a lot of doppler with that you need a lot better time differentiation than that the frequency is given to the megahertz note that the megahertz is the megahertz of the receiving station now i'm looking down at my little 7300 i have not checked it in the last several months for frequency accuracy i think it's within a few hertz well this is down to the hertz but if it's only accurate too few hertz that means that the last couple digits of that are not necessarily worth anything now here's the drift during the period of time in hertz between the time the receiving station started to receive the station and the time it finished receiving it the drift numbers are quite small but can be large if you're using a radio that is not entirely frequency stable it's an an older radio or something like that here's the call sign of the sending station and the grid square that's the only location information you have is en61 here which is quite a large location if you're on the ground like i put down my grid six digits as dm 68cg which narrows it down but still doesn't narrow it down to where you wouldn't have to do kind of a search to find it so en61 is several square miles okay of uh possible receiving area so that's going to throw off anything you're trying to do with the reception the dbm is my recorded this is the transmitted signal strength right here okay this is over here is the received signal strength compared to an arbitrary local reference and this is the number of miles from the center of this grid square to the center of my grid square now given each grid square covers several square miles at the four digit level this could be off by a few miles okay so that gives you an idea here is my basic transmit frequency and then these are the received frequencies in here a 10 10140206 this is the dial frequency and it's upper sideband so all the actual frequencies are going to be higher this is up from that reference frequency here now i want to take a look at something you can go online as i mentioned to whispernet.org and you can click on the map and you get a map of the whole world now i want you to notice two uh things here first of all the density of hams on the u.s east coast there are gobs and gobs and gobs this is only 30 meters okay 30 meters and this is the density on the east coast look over here western europe and the uk again this is on 30 meters is extremely dense there are a lot of transmitters okay a lot of transmitters now if we look over in the area where the flight went down the density suddenly disappears i've actually zoomed in on this a little bit okay the flight left um i believe malaysia okay and took off this way and this is the area that's been searched a lot in here now see these french stations here these are on an island called reunion and i don't know how to pronounce that in french some of the debris has drifted from the original crash site and landed on reunion island and a little bit on the north coast of madagascar which is right there and this is africa over here so clearly the plane did crash and it did break up it was a terrible crash no one could have survived it all that's coming over here are bits and remnants from the original crash uh some aircraft components are made of a kind of a honeycomb sort of foam type thing so they can float pieces of them can float the main airplane would have gone gone down now let's look at what we've got remember that this is taken at the same time as this one right here here's your us here's your european here's reunion and then there are a few in the perth area and a few on the east coast of australia there are a tiny number up here in the philippines and india who participate in whisper and you've got some new zealand so in terms of having a number of stations transmitting say for an aircraft right there you don't have very much over here so the data is going to be sparse now let's take a look at direct reception or multi-pass all right let's suppose we've got the airplane here and i'll just draw it as a a little across there's an aircraft it's got tail okay and you've got a whisper station here and a whisper station receiving over here now you're going to get the direct path on the signal okay you're also going to get an extremely weak multi-path reception as it bounces off this and comes down here you can measure the distance that it varies from this line by looking at the delta t as it comes off of here okay now one of the problems that you run into with this okay is first of all the whisper transmission time the whisper packet is two minutes not seconds two minutes long okay meanwhile the speed of light at um let's see it's 186 000 uh miles per second or 300 thousand meters per second and if i've got that right i may be off by about three orders of magnitude okay this can go around the earth seven times 7.5 times around the earth in one second okay that's the speed of light so the multi-path here could be measured with a fine instrument like a doppler radar the distance in time right here i did something in the general class licenses when we were looking at multi-path showing that for packet which transmits a complete packet in a very short period of time how individual bits in there can disrupt each other if this is only a few miles off okay so we're looking at multi-path here the thing is that the signal for um let me find the right one here you've got two minutes from the time this starts transmitting here sorry i don't have something that makes white two minutes from there to there okay two minutes and so any multi-path will be swamped in there and the direct signal will be much stronger now there is the possibility of this signal being the only one that's heard that the the direct signal is not heard but a signal bounced off the airplane could be heard okay and again two minutes it wouldn't be enough off from the two minutes to look like it would appear on this thing here again they're two minutes from there to there the multi-path would be fractions of a second and it wouldn't show up because again um you're measuring only tenths of a second in terms of the delta time you're not measuring down to the microsecond you're measuring just tenths of a second ten to the minus one seconds okay and the received frequency here is measured by uh the receiver okay so in terms of direct multi-path the problem is that this transmission is so long and the way it is detected is by sending the signal here through an algorithm that pulls out a very few number of bits and pieces and from that estimates these other things over here now it's only one hertz off i want to show you what happens with doppler now okay doppler you remember the old thing with the the train okay as it goes by a crossing it's sending its frequencies here toward you and you get the speed of sound plus the speed of the locomotive and over here the locomotive is receding from you and so you take its speed and you'll hear a difference in the frequency okay and this is sound of course which travels about 650 miles per hour or about a thousand kilometers per hour okay speed of sound and you hear that type of thing go by well that can be used by radar systems and is used by radar systems okay the first radar that the british used was a doppler radar and i did some calculations and let me see if i can find them here okay um one and a half times ten to the minus 6 times the frequency so if the frequency is 10 megahertz um you would get 10 hertz 15 hertz 15 hertz difference in frequency okay 15 hertz now that's definitely capturable here it's 15 hertz okay will it show up here if this is shifted and i mean we got 200 hertz if it shifted by 15 hertz would it appear as a separate signal yes yes it may very well now the problem is that you've got to compare the doppler from several different stations and given that we don't know the see we've got this dt over here this um this is the time okay but we're talking hertz now suppose that this hertz changed by 15 plus 15 hertz how would you tell what are you comparing it against you've got to have some form of comparison that's the thing about doppler radar doppler radar gives you the speed now if you've got this aircraft going this way and your doppler receiver is right here it's looking this way it'll get that full speed but if it's looking this way it only sees a component of it that component right there okay you need multiple radars reflecting off of something or very precise electronics such as it's found in modern radars to calculate the position when the data that you have is speed okay if you have a couple different places like the british used to do in their chain home you'd have multiple stations listening and they would get different frequency delays and they were able to get a pretty good idea of the position of the aircraft that was flying over the channel note that the transmitters were quite high power okay and the receivers which i believe are on separate towers where the best money could afford at the time which was an hro or something like that and they used phase differentiation to track the radios they used a little device called a goniometer but anyway now how do i know about this sort of thing well i was in radar in the air force way back when learned how different kinds of radars worked i also have a master's degree in engineering which deals with communications for example satellite signals and stuff like that and i spent a fair amount of amount of time studying modulation theory and even into the radar equation and so on so yeah i've got some history on this and i'm telling you that what they've got here you know until this hymn from britain reveals his material in a technical paper that can be peer-reviewed we don't know now if you want let's see if we've covered all the topics that we wanted to cover doppler okay we've talked about the fact that whisper is not a big thing in that part of the world we talked about direct reception and the possibility of multi-path which will give you inter-symbol interference but whisper is designed specifically to avoid inner symbol interference okay that's why it sends the same thing over many times and there are codes that you can use ways of bit fiddling uh to avoid the problem of inner symbol interference in a received signal because it is a problem in radio communications we've talked about doppler how the the traveling of the aircraft probably at about 500 miles an hour mach 0.8 ish would give you some doppler but what do you compare it with maybe this ham has found something to compare it with i don't know now i just wanted to talk about some other investigations there there's a whole hobby built up around this this is and i'm gonna just hold this here you this is a two line url https slash colon slash mh370.radiantphysics.com [Music] 2021 1219 whisper can't no hyphen can't find mh370 ended with a backslash will or a forward slash will take you directly to the article that talks about this is by victor ianello okay and he contacted joe taylor and this is what joe taylor had to say now this is victor speaking so this is technically here state i understand that but i can't find a direct article by joe taylor but he says i asked joe taylor for a comment on the material covered in this article here was his response shared with his permission now this is joe taylor speaking as i've written several times before it's crazy to think that historical whisper data could be used to track the course of ill-fated flight mh370 or for that matter any other aircraft flight and then this little zinger here i guess he's tired of getting this question i don't choose to waste my time arguing with pseudoscientists who don't understand what they're doing well am i a pseudoscientist i suppose i might be i'm a ham but i'm also a degreed engineer so my bottom line on this is until someone like joe taylor has passed judgment on a technical paper written by this british ham and has looked at the equations and the data and someone else has been able to duplicate the results until that happens i don't believe it okay and i don't think you should either great conspiracy theory but no i don't think so so there you have it if you would like to help this channel flourish you can put a little money in the pot by going to dcassler.com support if you would like to submit a question the best place to submit a question that you'd like me to answer would be to send it to my column in qst which is to ask dave all one word at a-r-r-l.org.org not net.org okay and i'm choosing from those to make these and i will also choose from them to put things into the monthly column in qst that goes by the same name as dave so until we next meet 73 [Music] you

Channel: David Casler Ask Dave

Views: 28,442

Keywords: ham radio, amateur radio

Id: zN6-qRS24AM

Length: 28min 31sec (1711 seconds)

Published: Sun Mar 13 2022