As a child, I used to go to the clearest AM radio station if storms were near and listen for loud crunches in the signal. Would give me an idea how powerful the thunderstorms coming were.
ב''ה, pretty much every receiver ever doesn't need a carrier present for this; some detail on how the broadband noise 'emulates' one to result in the audio output would be a nice demonstration of receiver theory.
When I used to have a 27Mhz cb radio, I liked to switch it on during a thunderstorm and listen to the lightning coming through the radiofrequencies. I could also hear the whistles from sunspots or solar flares and chirps from cosmic rays hitting the atmosphere or magnetosphere.
I've been fascinated by the idea of listening to electromagnetic signals for years. For those interested, it seems to be possible to hear the noise local lightning makes by tuning to an otherwise empty spot on the AM radio band. In my car, I've picked up what I think is the noise of lightning (sharp bursts of static), the hum from powerlines, and noises from those vehicle-detection loops in roads. And a handheld AM/FM radio will pick up stuff like the noise from switch-mode power supplies quite nicely, too.
Oh man you did a video on the thing that got me into HAM radio! One book I've found that is basically an atlas of things you see in VLF is "Whistlers and Related Ionospheric Phenomena" by Robert A. Helliwell. Dover sells reprints on it and I definitely recommend it to anyone into VLF. It covers everything from whistlers to sferics.
As a kid, I built self-made telephone systems for our home and always wondered about that crackling noise that was on the line. Now I know what they are. Thank you!
VLF is the fundamental principle for all the lightning detection systems we meteorologists use. Lightning tells us a ton about how strong the updrafts and downdrafts are in thunderstorms. Lightning jumps can help predict tornadoes as well.
Man let me tell you this: Your channel inspired me to create one on my own. Like you said I should in the comment section months ago. You inspire us all with your research and projects. You are much appreciated. Thank you for the QUALITY content. cheers!
Spark Transmitters! Were the first experiments in radio transmission.. can also create broadband noise which interfere with technology. I made one when I was about 12 in the 80's with an oldschool relay and battery with an aerial wire attached, vibrating in a soundproof box to annoy my new stepdad watching HIS show on my (family room) TV. haha.. all through his show, the screen would be static, but my channel was perfect.. (turned relay spark transmitter box off) hehe.
A few years back before their takeover, when Wunderground's Wundermap rivaled professional meteorologist tools and wasn't a steaming pile of bloated garbage, they had an awesome lightning map which showed cloud-to-cloud and cloud-to-ground strikes. I always wondered how that was done. It seemed like black magic to me and I never managed to stumble upon the methodology. Thanks for finally answering my questions. Also, thanks for the links, I'm going to spend a lot of time listening to these in the background.
its fun to connect a small photovoltaic panel to headphones. Then you can hear lightning strikes immediely. Each has very different sound. After hearing for a while you will know what kind of sound will produce a really hefty thunder several seconds later.
Lightning generates a spectrum of noise, from the MF to the VLF band. The higher frequency noise pulses are attenuated more rapidly and this is a method of determining the distance to the strike. There are small devices tp clip on the belt for use outdoors, hiking, mountain climbing, golf etc, which detect the MF and LF noise and give an approximate distance.
Fun fact if you take a headphone jack with a very long wire and plug it into the microphone then download a program called saqrx which is vlf software to view it then you can see vlf signals which is pretty cool. Edit: I recommend sdrsharp instead of saqrx since sdrsharp has more features
So, back when I had to study all this we never actually covered atmospheric wave guide propagation and your explanation has me wondering if a soliton packet could be injected into it and whether data could be modulated into it. Have you seen any literature referencing such a feat?
This might be obvious but... if you're making it of course you can. If it's naturally made I wouldn't imagine there is an easy way to do so. The sub communication is fascinating and most of their communication is done on ELF. Extra Low Frequency. A lot of time and money was put into it back when we had the polaris missile (nuke capable) on the trident sub as a first launch capability near the end of the cold war. For its time it was very impressive. It also included a 11 mile long antenna array in colorado you might look up. You might enjoy it.
A part of me really wants to get a VLF radio... But another part of me wants a hand held version specifically for man-made VLF emissions. A few years ago, I decided to chain a bunch of transistors together to make a long darlington chain, with a 15cm antenna... Damn, it was so interesting walking around the house with some earbuds plugged in, powered from a small battery and just pointing the antenna at things to hear their radio emissions.
Hey man. I ended up seeing this video when it came out, and I recently got a HackRF One, and this allowed me to look for similar phenomena. Thanks for giving me something new and cool to look for!
Fun fact: E layer of the atmosphere was the first one to be discovered and they decided to name it E just to have a bunch of letter both before and after it to have them reserved for later use. However, turned out that before it was only one distinct layer (D) and letters A-C ended up being forever reserved and unused. That sounds like some IT standard development doesnt it?
4:08 why does the graph say "Kelvin meter seconds" though. /s jokes aside i always had mad respect for lightnings, i mean isn't the cloud to earth thing just a giant capacitor? and a lightning is "just" the voltage building up so high that it breaks through the dielectric
Great video, have always been interested in learning more about the ionosphere, and this also serves as a great update to your previous video about VLF On the subject of radio, though, what's happened with your SDR stuff? I haven't heard a peep about it in months. You had ambitions plans about rebuilding Pipsqueak and mounting him in a radome when summer came around
Got busy with other things. This is why I stopped making update videos. Beyond no one really watching them, I'd get people excited for a project before getting distracted or busy with a different one. As with all of my projects, I will get to it eventually, but I pick the things that I find the most interesting at the time so I don't get bored and burnt out. That said I have actually been working on it in the background, just hasn't made it into media. Found a place to set it up permanently, but will need to wait for next summer as the season's already basically over.
i recently got a device called an Ether that can listen to a very wide spectrum of electromagnetic frequencies and listening to a thunderstorm seems to get sounds that just miss the very low radio waves leading to just some dry crackling. still very cool
I really like your device because it is very sensitive and can produce those sounds, unlike mine, which only rings when it detects a strong electromagnetic wave.
he ment it more in teh sens that you have to be near the poles where they so to say enter the gound more since the signals follow the lines. the densety of the socal feild line is higer near the polses
If you’ve ever seen ferrofluid under influence of a magnet, you can see that there are regions the fluid congregates towards and forms pointy nodes which depend on the strength and location of the field. The regions and nodes can be remarkably consistent with respect to the location and strength of the magnet. You can almost always predict where the fluid will flow to if you’ve seen the same state (of the magnet wrt. the ferro fluid) before. Now, are those places/points of congregation where those pointy nodes show up actual, physical “field lines”? I’m not sure, but it is tempting to call them that. (edit: typo/parenthesis)
When I was little little I would turn my radio on during a thunderstorm, and I thought it was so cool that I could hear a burst of static and see my window light up at the same time. Thought I was the world's greatest physicist for "discovering" it
@12m46s: Direction finding is actually by means of timing. The data is time-stamped using GPS derived precise time. The diagram shown mentions T1, T2, etc. i.e. time, not directly direction until the location is pinpointed via the timing.
@12m59s: Note the green LED marked "GPS". The GPS data of course gives the location of the receiver, but also the precise time stamp of each noise burst. The antenna shown is clearly not directional.
Lightning, aka "whistlers' mother" . . . A nice summary focusing on ground-based VLF recordings. I host a historical archive of Steven McGreevy's material at www-pw.physics.uiowa.edu/mcgreevy Two minor corrections to this video: The "dawn" in dawn chorus doesn't really have anything to do with local time; it's merely a reference to the morning song of jungle birds that the signals sound like. Also, it's my understanding that the VLF emissions don't push away the Van Allen belts, but drain it near the Earth. Also, if you want to hear similar space audio recorded by spacecraft . . . you know where to look.
How can you possibly pick VLF under ocean, when the ocean's salty water is incredibly conductive (and you've mentioned in the beginning that it's a very good reflector)?
A bit later, I thought that while electric field is screened very well by the conductive water, the magnetic field can potentially penetrate a lot deeper. How much deeper? Well, that is called "skin depth", and it can be easily calculated given the resistivity and the frequency. For ocean water resistivity, I found a value circa 0.2 ohm*m. For 1kHz, I calculated the skin depth to be 7 meters. So, a submarine whould be able to pick something up, but only if it is quite close to the surface. Below 20 meters it should fade to nothing.
The conductivity just tips the wave a bit so it can curve enough to not leave the atmosphere, doesn't really impede it, so it penetrates water just fine. Also, not much of the energy of a lightning bolt ends up as VLF. It's enough to pick up, but not a huge amount. Whereas for military stuff they blast copious amounts to get it where it needs to go. Also a lot of the reason radio has issues penetrating the ocean is because of the air water interface. Once it gets past that it can travel further. VLF mostly ignores this interface so it's already in a good position to keep traveling.
@@thethoughtemporium And what's the deal with the interface? Is it too reflective? or too irregular? As for reflectivenes, VLF seems to be the point where it's the highest, as it is where dielectric permittivity of water is the highest (circa 100, so refractive index is 10). So it's worst for reflectivity. Then in the microwave it drops and gets a high imaginary component, meaning high absorption coefficient. then we are approaching the light territory...
A lightning powered Tesla coil would be the ultimate Mad Science Project though too large-scale to be practical, but capturing lightning with a rocket and steel wire seems the sort of thing these guys'd be well capable of, with perhaps a coil gun or the like at the end, we can't all have a Flux Capacitor :) Great video as always of course.
I used to listen to VLF a lot. The trick was to either go to a desolate location (freeze to death in a car late at night) or use a repeater to send the sound to a more convenient place. It is very hard to predict the occurrence of VLF emissions and whistlers, therefore one should just record all night and later look at the spectrograms to reveal the interesting events. These days Audacity on any computer with a sound card can easily record for hundreds of hours at a time.
To me listening to SW/AM/LW is like listening to the world, esp in summer. I can hear thunderstorms before they arrive, and many times I can see the light flicker at or from below the horizon, then, in an hour it takes off, right over my house
Im a guitarist and my amp makes a weird static noise when a lightning strikes. The weird part is that the sound of the lightning is heard first from the amp.
At the 3 minute mark just casually make the point that the wavelengths Tesla was working with a century ago do exactly what he said they did. A century ago.
@@johnpossum556 When he's describing the propagation of VLF waves at the 3 minute mark. In his time Tesla was saying he could use VLF to send messages across the Atlantic and because everyone was using hertzean wave mechanics that said EM waves travel in straight lines no one would believe him. Then Marconi used Tesla's equipment to send messages across the Atlantic and claimed he did it first. Despite a massive amount of evidence that Tesla had transmitted signals further over a decade previously.
But how could you record the vlf signals from that city in Germany, even though it doesn't exist? (It's a local joke in Germany to claim Bielefeld doesn't exist )
I recorded a lightnig too by recording my audio amplifier with a long cable attatched xD But only nearby lighnings are possible because everything else is too silent.
Yep. You can also connect a long wire to your computer sound card's mic input which is very sensitive - works well as a VLF receiver, and you can use an application like Spectrum Laboratory to view the signals. Be careful though, as excessive static voltages on the longwire can damage your computer! I connected mine through a capacitor and a large choke to attenuate higher frequencies that can overload the input such as local MW transmissions (actually the secondary winding of a MOT) and with a bit of playing around, it works very well.
It doesn't work nearly as well as one of the receivers. I've tried it and it mostly sucks. Your computer throws a ton of noise so it's hard to pick out the useful signals and there's no amplification so it's gotta be from a storm much much closer to you. That's actually part of the reason I made this video, I had an old video that uses a sound card and the results are night and day comparatively.
@@thethoughtemporium yes, computer noise sucks. even from a security point of view, as i heard it was possible to extract some information linke keystrokes from that. but as i said, it only works for nearby storms. if you cant see the lightning, you almost cant hear it.
I like that the drawn earth (with magnetic field lines) is the 100 meter sea level rise representation, an excellent touch to keep the video accurate for future viewers. Great video btw, keep it up
oh damn I saw these when I got a cheapo SDR a few years ago and I had no idea what they were and none of my friends could figure it out either, that's rad.
about your geko tape , i found a good sorce of a material suitable as a mold , it is the poralization filter from an lcd montor , i iven had one thst stuck to my closet althoagh i feel like it was more electrostatic related but still
This reminds me of, when, As a kid I used to like listening to the strange sounds in abetween radio stations and particularly at the ends of my radio's dial.
From the description, these ultra low frequencies make me think of that project the Tesla wanted funding for. Something about a tower that could use the Earth itself to transmit energy, which would be available to anyone with a receiver… I vaguely remember some talk of putting up a lot of them, and making energy available to everyone. Was he trying to use ULFs to achieve this?
Probably. That it certainly possible, but it would most likely give everyone cancer and not be able to enter cities. However if you are interested in this topic I suggest you go research into radio galaxies, as they have quasars in the center that are so powerful that anyone in the galaxy could just build an antenna and get free power from light years away
In Australia when you scuba dive you will hear that very similar sounds which indicates a healthy reef with crayfish. The louder the clicking the more crayfish in the area.
