11 ms·
What 50,000 watts of RF energy sounds like through a jumper cable
- gnu8 11y agoFlagged for linking to facebook.
- ronreiter 11y agoWhy is that an issue?
- gnu8 11y agoWhy wouldn't it be an issue, unless you're a shareholder?
- jrockway 11y agoI've noticed that a lot of users have various vendettas against certain companies, and they like to pretend to be outraged whenever they have any opportunity to mention their dislike for the company. In this case, a link to Facebook was provided, so it was the perfect opportunity for a rant about Facebook, right? (In the case of gnu8, it appears they merely hate everything unilaterally which I suppose is refreshing. Probably just having a bad week.) Meanwhile, there are plenty of things Facebook could have done to be annoying, but they didn't do those things. I don't have an account. The link loaded fine. What's there to complain about? The web worked like the web.
- exodust 11y agoAnti-rant? I got the "you must login to continue" prompt on Facebook, but managed to save the video and upload as a good old static mp4... the video is low quality, as is the version on FB. http://ozimg.s3.amazonaws.com/video/RF_energy_through_jumper_cable.mp4 http://ozimg.s3.amazonaws.com/video/RF_energy_through_jumper...
- ronreiter 11y agoWow, can anyone explain this?
- xwintermutex 11y agoI guess it is because of the use of amplitude modulation [1], where the envelope ("strength") of the carrier (that is some higher frequency signal) follows the signal that is modulated onto it (speech, in this video). With say FM it wouldn't work, I presume. [1]: https://en.wikipedia.org/wiki/Amplitude_modulation https://en.wikipedia.org/wiki/Amplitude_modulation
- jimmaswell 11y agoIf you listen to an FM signal interpreted as AM you can often still make out the audio, it'll just be very clipped and noisy. That was the result when I did this with an RTLSDR, at least
- AndrewKemendo 11y agoSame way as a plasma speaker https://www.youtube.com/watch?v=PJpn2PzhvP4 https://www.youtube.com/watch?v=PJpn2PzhvP4
- okbake 11y agoIt would be cool to see a guitar amplifier that worked like this. It seems dangerous, but that would be awesome to hear/watch.
- JoshTriplett 11y agoOr, on a larger scale, a Zeusaphone/Thoremin: https://www.youtube.com/watch?v=3ff_AXVlo9U https://www.youtube.com/watch?v=3ff_AXVlo9U
- jakeogh 11y agohttps://www.youtube.com/watch?v=hgll-XTqcS4 https://www.youtube.com/watch?v=hgll-XTqcS4 (youtube-dl with mpv fullscreen recommended)
- skrpwr 11y agoThis works with plants too. https://www.youtube.com/watch?v=6Scm-tKTHls https://www.youtube.com/watch?v=6Scm-tKTHls
- connorlee 11y agoAmplitude Modulation, or AM, works by modulating the sound on the "peaks and valleys" of the frequency. If you were to look at the waveform of the carrier frequency, you would see it as variance in the "power levels" of the signal, going higher and lower depending on what's being sent. Because of how AM works, you can actually hear what's being transmitted by causing an electrical arc. It's the same concept of hearing a "buzz" from high voltage power lines, except in a controlled fashion to produce sound.
- Already__Taken 11y agoSo could you tune into the singing tesla coils with an AM radio is that the same idea?
- pdkl95 11y agoYou probably could, though I suspect you might need to re-tune between notes. If you have an old CRT, you might be able to achieve a similar effect with Tempest for Eliza[1]. [1] http://www.erikyyy.de/tempest/ http://www.erikyyy.de/tempest/
- jackhack 11y agoIndeed. One of the more interesting projects I've seen uses a tesla coil discharge as a guitar amp: https://www.youtube.com/watch?v=glrPioGqu3s https://www.youtube.com/watch?v=glrPioGqu3s A search for "singing Tesla coil" will turn up many more.
- xhrpost 11y agoCame here to ask this very question. Thank you. I take it then that a signal using frequency modulation or phase modulation (is that done anywhere?) wouldn't work then? Also, probably the same reason a ground loop in a home entertainment system will pick-up local AM stations. Edit: also, why does this work with the given RF frequencies which for AM are still much higher than audible sound frequencies?
- LesZedCB 11y agoElectroBOOM has a cool video[1] on youtube talking about some of that! His videos are some of my favorite. [1] https://www.youtube.com/watch?v=L5E4NiP4hpM https://www.youtube.com/watch?v=L5E4NiP4hpM
- tlrobinson 11y agoEven better: some crazy Russian/Ukrainian kids listening to the local radio station through weeds (and occasionally getting some minor RF burns): https://www.youtube.com/watch?v=82s5Q3GIO9I https://www.youtube.com/watch?v=82s5Q3GIO9I
- voltagex_ 11y agoI don't think I'd want even minor RF burns - nasty nasty stuff.
- therein 11y agoWhat makes it worse than just a burn or a burn due to an electrical shock?
- voltagex_ 11y agoI can't find the reference but a ham operator once told me they can be imperceptible while they're happening.
- tjohns 11y agoNormal burns are usually localized to the surface of your skin. RF burns conduct all the way through your tissue, heating from the inside. It's a much deeper, more painful burn that takes an abnormally long time to heal. (Or so I'm told. So far I've been able to avoid experiencing one myself.)
- jacquesm 11y agoUnfortunately I wasn't able to avoid the experience, I hit the screw on a silver trimmer in an end stage while looking at another one. Nasty little burn with dead tissue in the center and living tissue all around it. 35 years later it is still there, I don't expect that it will ever properly heal, it's a dead bit in the middle of a living finger.
- 11y ago
- exabrial 11y agoSo dumb questions: Why were they shorting out the tower? (What was the purpose of the cable) What are those rubber things? What would happen to a bird that landed on the tower (not grounded) What about a large metal helicopter (if it didn't crash)?
- vkou 11y agoThe bird would be fine, due to the way parallel circuits work (Very little power travels through the more resistant one of two parallel circuits.)
- jacquesm 11y agoThe bird would be dead. RF power will happily fry tissue if you get close enough to the radiator.
- eknkc 11y agoWhy isn't there a bird / bug / etc cemetary at the base of the tower?
- gcb0 11y agothere is. it's very, very noticeable on micro wave towers. the drum like cover on microwave antennas is just a lame regulation to try to save birds. they still die just by passing by. the building were i lived had one that required constant "maintenance" (dead bird cleaning)
- sathackr 11y agoI have never seen this, and I work with microwave towers nearly every day. The 'drum like cover' is called a radome, and it's primary purpose is to reduce the wind loading of the microwave dish. It also serves to protect the usually sensitive feedhorn inside the dish, keep out bird nests, ice, water, etc... The common cause of bird deaths around radio towers is collision, not RF energy. In Florida it is very common to see osprey nests build on/in/around towers. Microwave dishes are a common location because they provide a large horizontal surface to support the nest. See Wikipedia article 'Towerkill' https://en.wikipedia.org/wiki/Towerkill https://en.wikipedia.org/wiki/Towerkill
- deleted 11y ago[deleted]
- elaus 11y agoIn my home town we have a large broadcasting tower for MW/UHF radio and a lot of the elder people tell stories about how they were able to listen to the radio via the plants (e.g. cucumbers) in their garden
- osoti 11y agoWhat Would Happen to our Earth if the Sun Disappeared? http://goo.gl/Bvpsr1 http://goo.gl/Bvpsr1
- estomagordo 11y ago19 comments and not even one mentions that Watt, with a capital W, measures power, and not energy? I'm assuming 90% of posters know this, but it still bugs me. A modest proposal: "What 50 kilowatts of RF power sounds like through a jumper cable"
- Nutmog 11y agoI think that usage is OK. It's like saying "40W of light". In this case, it tells us there's some RF energy and also that it's RF energy of the "50 kW" type.
- estomagordo 11y agoI think "40 W of light" is a great example of why this imprecise, or quite frankly, incorrect usage is troublesome. 40 W of old timey lightbulb light is useful if you want to sit close and read a book in the evening, whereas 40 W of a modern LED bulb light is a great thing to have if you want to fend of a pack of marauding undead.
- klodolph 11y agoIt's not actually as imprecise as it sounds. A 40W light bulb might produce 1W of light and 39W of heat. Watt is the normal unit of measure for radiant flux, and the lumen is nothing more than "luminous flux" which is radiant flux weighted according to its spectrum.
- zurn 11y ago"40 W of light" in physics terms is quite unambiguous, it means 40 W in radiant flux.
- estomagordo 11y agoI'm aware that it makes sense to talk about light flux in terms of Watts, I was more getting at it not being obvious what the person using that terminology actually means.
- SixSigma 11y agonitpick - watts is a measure of speed - joules per second
- Nutmog 11y agoI'd call it a rate, not a speed. Speed is specifically distance per unit time, not energy per unit time.
- xupybd 11y agoGood point but even then we tend to use power when talking about energy per unit time.
- ridgeguy 11y agoJoules = energy (how much work you can do) Watts = power (how fast you do the work)
- SixSigma 11y ago50kw for 1 nano second is not going to have much of an effect
- madez 11y agoI can’t watch this video without an account. A click on the video leads me to the login page. Is there a mirror?
- symmetricsaurus 11y agoI got a login screen that popped up after a while. Pressing ESC got rid of it.
- deleted 11y ago[deleted]
- hudibras 11y agoI don't have an account and it played fine. No explanation of why tho.
- phantom784 11y agoI think it depends on what country you're in. In some countries, they have to block pages if you're not signed in for legal reasons (since they can't legally track you).
- igravious 11y agoI don't have an account and it played just fine. Don't know why though because normally I get a login page like yourself.
- doguozkan 11y agoYou could try unblocking Facebook domains if you're using Privacy Badger.
- redblacktree 11y agoAnother poster shared a direct link to the CDN, may help: https://video.xx.fbcdn.net/hvideo-xlt1/v/t42.1790-2/12709279_1695997427283635_55022438_n.mp4?efg=eyJybHIiOjM2NSwicmxhIjo1MTIsInZlbmNvZGVfdGFnIjoic3ZlX3NkIn0%3D&rl=365&vabr=203&oh=1f3406291ae0de3e377fc3c4d1e3d88e&oe=56BCAA54 https://video.xx.fbcdn.net/hvideo-xlt1/v/t42.1790-2/12709279...
- nielsole 11y agoI was once in a completely empty swimming pool (~25*10 m size) The surface of the pool was completely undisturbed. When I put my head under water I could hear a radio voice. Since I could not rule out the possibility that it was simply audio from nearby speakers that I simply could not hear through the air, I was always wondering whether it would be possible to listen to radio waves in water.
- andromeduck 11y agoYou probably can't because, if nothing else, the water should act like a faraday cage.
- Piskvorrr 11y agoYour first explanation is far more likely: water conducts sound waves far better than air.
- tombrossman 11y agoUnderwater speakers exist (think synchronized swimming or a PA system at a public pool). The sound quality isn't super but voice quality is good. Is it possible the pool was equipped with one?
- stefanix 11y agoBehind login wall.
- philh 11y agoDoes a tower like this only broadcast one radio station? That's not what I would have naively expected. But if not, why do they pick up that specific one?
- beedogs 11y agoAM towers can broadcast more than one frequency at a time, but I'm not sure how common it is in practice. http://www.radioworld.com/article/four-am-stations-sharing-one-site/220752 http://www.radioworld.com/article/four-am-stations-sharing-o...
- sathackr 11y agoI've never heard of it, but as the other reply mentions, it's possible. If you are near an AM station, you can make a radio with just a earphone(now called ear bud?), a diode, and a piece of wire. You will pick up all nearby stations, but one will likely be stronger/closer than the rest, so you would hear that one. A slight improvement of that is the 'crystal radio' that adds the ability to tune to a certain station. [1] It is common for people living near AM stations to hear the radio signal induced into their house/business wiring. It's a common problem with landline telephones near these stations, you can hear the radio in the phone while you're trying to use it. Intercom systems are also vulnerable. You've probably also heard this from time to time when someone with an illegal CB amplifier uses their radio near a business with an intercom system. It will typically briefly bleed into the intercom system, with everyone looking around trying to figure out where that noise came from. This may be common only in the south, I'm not sure how prolific CB radios are throughout the country. [1] https://en.wikipedia.org/wiki/Crystal_radio https://en.wikipedia.org/wiki/Crystal_radio
- kabdib 11y agoI used to live in Fort Collins, Colorado, a couple of miles from the antenna for WWV, the broadcast time standard from the National Bureau of Standards (that'll date me, it's called NIST now). Electronics was one of my hobbies. Most of the noise in my circuits was that damned time signal. I could pick it up with just about any length of wire and anything that would act as a diode. A transistor. A pin on a chip -- I had a DRAM coughing up "At the tone, the time will be..." once. At least I usually knew what time it was.
- gelo 11y ago50000W of RF power is approximately 355kV - if you work out based on that 1W dBm is 7.1 Volts.
- JohnDoe365 11y agoThe pictured parabola antenna likely has a gain around +20dB. Would that change your calculation?
- gelo 11y agoi don't think it would change (probably wrong) since the active energy is only generated by the final PA's in the system. the Antenna's gain is only from the passively reactive design. Its like making a violin string resonate by only moving the bow and not physically the string.
- gelo 11y agoi mis-read your comment - it has no affect at all as its not whats transmitting 50kW!
- cnvogel 11y agoNo. Power generally is proportional to the voltage squared (P∝U²). P=U²/R → U=√(PR) The numbers you quote (1W [not dBm!] is 7.1V) make me believe that you assume an impedance of 50Ω. In [1]: math.sqrt(1*50) # P[in W] * R[in Ohm] Out[1]: 7.0710678118654755 # U[in V] So, in an hypothetical cable of 50Ω impedance, 50kW of RF power is... In [2]: math.sqrt(50e3*50) # P[in W] * R[in Ohm] Out[2]: 1581.1388300841897 # U[in V] about 1.6kV(RMS). Note, though, that with large installations it is likely that there are a few individually tuned feeds. And the cable might not be a 50 Ohm cable, but maybe a chicken ladder (two strands separated by fixed spacers), large-area waveguide, ...
- gelo 11y agoeh i wasnt expecting to be right. Although i would say they usually use heavy duty coax at 50ohm - i believe - not sure though
- gelo 11y ago50000W of RF power is approximately 355kV - if you work out based on that 1dBW is 7.1 Volts.
- luxpir 11y agoA link to the CDN-served file directly, if anyone wants it: https://video.xx.fbcdn.net/hvideo-xlt1/v/t42.1790-2/12709279_1695997427283635_55022438_n.mp4?efg=eyJybHIiOjM2NSwicmxhIjo1MTIsInZlbmNvZGVfdGFnIjoic3ZlX3NkIn0%3D&rl=365&vabr=203&oh=1f3406291ae0de3e377fc3c4d1e3d88e&oe=56BCAA54 https://video.xx.fbcdn.net/hvideo-xlt1/v/t42.1790-2/12709279... Not the prettiest thing, but there you have it.
- i336_ 11y agoThis is now returning "URL signature expired". The guaranteed way to do this is just to grab and use youtube-dl. It supports almost everything nowadays, and it's where all the updates and maintenance goes. Passing the OP URL got me a copy of the video perfectly.
- w8rbt 11y agoNever touch or even stand close to an antenna that's transmitting. Even small mag loops with 10 watts of power will cause serious burns if touched.
- snarfy 11y agoPower transmission lines have a similar effect when they are disconnected. My father was a lineman and told stories of hearing radios, intercoms, etc when working with HV lines.
- carapace 11y agoIt is a plasma speaker? https://en.wikipedia.org/wiki/Plasma_speaker https://en.wikipedia.org/wiki/Plasma_speaker
- trhway 11y agoso, pedantically, it isn't through the jumper cable - the sound is generated by plasma between the cable and the tower. I think i heard something about "plasma speakers" before.