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DIY Texting System For Really Underground Radio
Gulthek writes "Sixteen-year-old Alexander Kendrick has created a device that allows texting and other data transfer from almost 1000 feet underground. The tech could allow rapid emergency communication with the surface and opens the potential for scientific measurements without the need to continually visit (and disturb) the cave environment." There's some kvetching in the NPR story's comments that it's not the first use of cave radios, but that seems to miss the point.
Damnable overachievers...
I guess Mom's basement goes really deep underground for this guy. Perfect technology for nerds everywhere! Why risk your pasty white skin getting outdoors to text?
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This doesn't just apply to caving, it should work as well for mining no? Range shouldn't be an issue since if it uses radio then relays should be feasible.
Reduce your bit rate to a few bits per second, even fractional bits per second, and you will be amazed at how far you can get a signal with a minimum of power.
"To those who are overly cautious, everything is impossible. "
But scientists think one of the biggest threats to this emerging source of antibiotics is actually the scientists themselves. In fact, researchers believe the more they visit a cave, the less likely they are to find antibiotics. People contaminate the sensitive cave environment just by being there. Northup thinks that by connecting data recorders to Kendrick's radio, scientists could remotely transmit information about the cave environment. "So a cave radio that allows you to beam data to the surface rather than visiting it in person can be extremely valuable," she says. "It could save the cave."
Frankly, this doesn't seem that likely since to check if something is a useful antibiotic it needs to be tested against actual cultures generally. However, this does have serious potential of helping and of increasing our knowledge base. General medical knowledge and more anti-biotics will likely save far more lives than using the technology just to rescue people who occasionally get trapped in caves.
I recall reading a story a few years ago about some protesters at Berkely using audio amplifiers to transmit information between their various members and groups. They'd attach the ground lead of the audio output of a 200 watt audio amp to a 10-15' rod pounded into the ground. The positive lead was attached to another, shorter rod, pounded into the ground several feet away. To recieve, they'd switch the wires from the ouput to the input of the audio amp. The claim was that they could send voice as an electrical wave several miles. Don't know how true the story is, but it sounds like it might work.
In central Nebraska, not far from Silver Creek, is a "Survivable Low Frequency Communications System" The wiki writes about it: http://en.wikipedia.org/wiki/Survivable_Low_Frequency_Communications_System/>
"SLFCS single channel, receive only capability is provided at ICBM launch control centers. The single channel operates between 14 kHz and 60 kHz to receive commands from remotely located Combat Operations Center - Transmit/Receive (T/R) sites; this low frequency range is slightly affected by nuclear blasts.". The signal travels along and underneath the ground, i.e., Ground Wave propagation. Because the frequency was close the the 60 Hz power line frequency the two 1 KHz side tones were used to track power line faults.
When I drove by the Sliver Creek antenna and tuned my radio below 550 Khz I could find a hetrodyne signal and listen to the characters being transmitted in 5X5 blocks of characters.
Running with Linux for over 20 years!
It sounds a bit like ELF. The problem with really low frequencies is you can't transmit large amounts of data and they require larger antennas. The military's ELF arrays are massive and are only good for launch codes. That's the reason he's talking about text messaging. A smaller antenna like he's holding could take a considerable amount of time to transmit even a paragraph of information. It might be okay for scientific equipment but I doubt it'll be practical for much else. There's nothing earth shattering here, it's been done at least since Tesla's time. The reason it was never pursed is there are practical limits and minimal commercial value in the technology.
No more out of range problems while I'm in my mom's basement.
You see? You see? Your stupid minds! Stupid! Stupid!
"In a 1991 New Mexico cave rescue, it took 170 people four days to save a woman with a broken leg. The rescue team had to lay miles of telephone line in order to stay in touch with the surface." "If they'd had Kendrick's radio, the rescue time may have been cut in half." When we go caving, especially a new one, or a rescue, Who wastes time laying phone wire? Teams are two, each with a different colour string with a wire core for added strength. This way we can follow different pipes simultaneously if its a complex cave. If two can get them out we do. Otherwise one stays one goes back. With all the gear we have who wants to be carrying all this stuff. If it can be made smaller the better. I guess my point is more about the Mexico rescue thing. Cool Idea kid!
who wants to start the first underground filesharing railroad
the morlocks would be happy! http://en.wikipedia.org/wiki/Morlock
Science advances one funeral at a time- Max Planck
Developed by Los Alamos National Laboratory, the Through-The-Earth Communication system proved capable of sending two-way, very-low-frequency (VLF) voice signals from the surface of the mine to depths exceeding 300 feet at the experimental mine operated by the National Institute for Occupational Safety and Health (NIOSH).
The Through-The-Earth Communication system was developed for the U.S. Department of Energy at Los Alamos National Laboratory's Superconductivity Technology Center with a development team led by David Reagor. The technology has also earned a prestigious R&D 100 Award from R&D magazine.
The system uses VLF electromagnetic radiation in the range of 3 to 30 kilohertz (kHz) and digital audio compression to transmit wireless voice and data signals through the earth. Materials that block higher radio frequency (RF) signals, such as rock, concrete, metal, and high-density ore bodies, do not restrict its signal
Incorporating Sprint/Nextel i325 mobile phones, supported by Raytheon's JPS Communications ACU 1000 cross-band repeaters, the Through-The-Earth Communication system demonstrated its capabilities in the Lake Lynn Mine, which is composed of several long tunnels used for mine safety experiments. The mine consists of nonflammable limestone with a tunnel height of about 10 feet and an overburden of up to 370 feet. Test Of Through-The-Earth Communication System Exceeds Expectations [August 2007]
VLF appeals to radio hobbyists because of its exotic associations with both natural science and submarine warfare. To get started all you really need is a PC and a home-made antenna. Radio Waves Below 22 Hz
for half an hour with a transmitter waiting for my friends on the surface to radio-locate the position on the surface vertically above me.
The transmitter fits in a 6 inch diameter tube - you'd never get an antenna like the one in the photo down a Yorkshire cave. The one used on the surface is much bigger, though.
The next project is to produce a cheap transmitter that a cave diver can carry into an aven and leave (they don't want to have to hang around), in the hope that once located a dig can be done from the surface directly above.
Here's a links to a UK cave radio web site
http://caves.org.uk/radio/
Anyone else notice that the guy said it was 68 degrees 1000 feet underground? With that much open air to the surface, it's not surprising he could get a radio transmission through.
so this is the bin laden comm system?
VLF systems have been in use for decades to communicate with the US Submarine fleet, not because of interference, but because it passes through just about everything and has a very, very wide propagation. Unfortunately, the power levels are so high that people wonder/suspect it's causing nature / health problems for nearby residents.
I mean for fucks' sakes, this stuff was in use by the German navy during WW2- 70 years ago. All this kid did was apply the obvious, and apparently, it's so obvious, someone thought of it 40 years ago. More info:
http://en.wikipedia.org/wiki/Very_low_frequency
Also, the kid didn't implement any sort of retransmission or error correction. That makes it pretty useless for both emergencies (imagine: "person has 3 hours to live" instead of "30 hours") and scientific data collection. It's also pretty standard these days.
Please help metamoderate.
First. I applaud this guy for making such a neat device. Listening to the story break on NPR this morning was rather captivating. The reporter made the device sound relatively small - something able to fit easily within a single cave-bag after disassembly. After seeing the antenna array, though, I thought my eyes would pop out of my head. There is no *way* a group of cavers are going to carry this contraption around *as it is*. It is certainly a prototype and the device certainly has merit but, for the sake of the device and the caver(s) carrying it, it is hoped (at least by me) that it becomes a lot smaller and still able to transmit/receive with the surface counterpart.
You see, a device as large as the one in the pictures on the webpage would be unwieldy in many, if not most, caves in the US as most US caves are not walking passage. In its current form it would suffer a lot of abuse and probably become submerged in water, covered in cave mud, bumped, sat on, kinked, bent, folded, dropped, hoisted, scraped and buffeted from a normal days wear and tear. If the antenna wire itself became broken trouble would certainly ensue. So, I don't see the current form of cave rescue going away any time soon. (The cave-trip leader has a designated person that did NOT go on the cave trip to call by a certain time. If the trip leader has not called that person by that time a cave rescue is supposed to be carried out.)
Don't get me wrong - this is a very cave-worthy pursuit and many a caver would feel better about having this technology along for the trip - as long as the equipment could withstand the journey. Otherwise, it's just more dead weight.
Second. For the story itself - caving is not 'relatively safe.' It's more along the lines of relatively dangerous. Why? Anyone entering a cave with the attitude of 'relatively safe' is bound to get hurt. Very recently there have been people who went out for a day of caving and came back sans one member. See this story
I didn't know this guy but it seems arrogance killed him. Hate me for it if you have to but he went into a passage where 2 other people had to be rescued from years earlier. It's shameful that the cave owners/grotto overseeing the cave didn't have the foresight or fortitude to prevent future tragedies by closing that passage or making the cavers sign a form detailing that particular passage as off-limits. He died a slow death as hypothermia set in while he was upside down in a passage. He was supposed to be experienced. I heard about his story while he was still alive and I prayed that he could hold on long enough for a solution to extricate him could be found. I'm heartbroken and angry for his needless death.
Thirdly. One part of the radio broadcast that this story didn't relay is a story of the famous (or is it infamous) rescue of Emily Davis Mobley from Lechuguilla Cave very near Carlsbad, New Mexico. I think the broadcast mentioned that this (the Lechuguilla cave rescue) was the reason why he invented this device. (I remind you to see the above paragraph on caving being relatively safe. Still think so?)
You Tube of the rescue: http://www.youtube.com/watch?v=J7I7bXcSWK8
Wikipedia Entry: http://en.wikipedia.org/wiki/Cave_rescue
Fourth. If you want to know more about caving visit Emily's website: http://www.speleobooks.com/
Finally: If you still don't believe me that caving is dangerous just you try cave diving. Near 100% fatality rate where 'accidents' have occurred. The rule of thumb is is something goes wrong while cave diving - you have two minutes to live.
Here's the official website for caving accidents in the Americas - http://www.caves.org/pub/aca/
FYI, There's NO FN WAY you'd get me to cave dive.
It sounds like he is using packet on HF. It is unfortunate that the article mentioned HF as being used for FM broadcast (that would be VHF). Amateur radio operators have been doing stuff like for a very long time. Big deal.
Carrier Wave (Morse code) would be way more useful than packet for rescue work. The only issue is that the splunkers would need to learn it. CW is a simple on/off sequence. It travels far, and is understandable even with a noisy signal.
The claim was that they could send voice as an electrical wave several miles. Don't know how true the story is, but it sounds like it might work.
Of course it will work.
Morse used earth conduction to bridge the Susquehanna River in 1842-3. CALLING ALL NATIONS -- 1941
Kids were taking on projects like this in 1913. How To Make A Wireless Telephone
Very Low Frequency (VLF) Stations [2010]
Ham Radio below 9 kHz [2006?]
It looks like there's a need for an approach along the lines of RFC 2549, but using chiropteran rather than avian carriers. Assuming that they can be trained, the bandwidth will be higher and the weight and volume to be carried by both cavers and rescuers considerably less.
Seriously.
If you're leaving a sensor in a cave or mine to gather data, its going to be there a while. Take a spool of wire with you on the way in and just hard wire the thing for data and power.
Wireless is rarely the right way to do things, especially stationary things.
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Alexander didn't "invent" anything. It's been known for decades that VLF waves will penetrate where other, higher, frequencies won't.
But VLF doesn't get used much in the real world because of it's low bandwidth, high power requirements, and the size and fragility of the antennas required.
Ah, Emily, a real nice gal.
Several of my Caving friends were involved in her "rescue".
My sweety and I gave her a party at our house on the one year anniversary of her rescue.
I had been exploring the Fubar Passage in nearly the same spot in Lech where the rock peeled away from the wall and almost crunched her (breaking her leg) on an expedition six months before, I had a narrow escape with a BIG rock peeling from the wall there as well.
Never mind that Hams used PSK31 (eg Digital coms) and Audio frequencies to communicate 30 km via Ground Currents some ten years ago...
This is pretty routine stuff...
Don't we already have a system that does exactly this called mole phone, sending text on VLF from deep underground is nothing new.
---
Ham Radio Feed @ Feed Distiller
caving is relatively safe
(sorry, couldn't resist)
my dad was an avid spelunker before i was born. thank god/darwin he kept the relative danger to a minimum, or i wouldn't be here
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
I think you'll find that CW has a signal bandwidth equal to or less than that of PSK31, when sent at the same data rate. If you doubt the textbooks, this is easy to see for yourself, by having someone send CW while you look at the signal on the waterfall display of your favorite PSK receiving software -- or just tune down to the CW portion of the band and have a look.
People often use filter bandwidths of 500 Hz (or even more) while manually receiving CW, just for ease of tuning, and let their brains do the "channel filtering" to separate individual CW signals present in that bandwidth. Similarly, people often use filter bandwidths of 2.4 kHz when receiving PSK31, just for ease of tuning, then let their computer do the "channel filtering" to separate the individual PSK signals present in that bandwidth.
You're comparing the signal bandwidth of PSK31, with the noise bandwidth of a CW receiver. The two are separate concepts.
> There's some kvetching in the NPR story's comments that it's not the first use of cave radios, but that seems to miss the point ..
It is a valid point - not the first ues. It does demonstrate skill for a sixteen-year-old to be ables to design and construpt the device. An amalgam of VLF radio and a digital device. Communication underground has always been a problem. Leaky lines are one such solution, either active or passive.
I was curious too, so:
"Aven" is a French loanword, though it doesn't show up in my little French dictionary, or in the Oxford English Dictionary for that matter. But I found a French-language online dictionary that basically says it's a natural well ("puits") found in limestone. Apparently it's a loanword in French as well, taken from the Rouergat (?) dialect of the Occitan language.
I glanced at a few English-language caving publications which translate "aven" as "big cavern", "cathedral", "sinkhole", "shaft", or "abyss". (That last one seems a little suspect, since there's already a French word for "abyss", abîme.)
Confusingly, a lot of these words have water-related cognates. "Aven" apparently also means "river" in Breton, and in English a "puit" can be a well or a stream.
(Disclaimer: IANA linguist.)
It's really cool that a news article finally came out about this kid. Some crazy science went into making this. Very cool.
this technology has been around and in common use, well for just about as long as radio has been around, LF communications for miners is allready in common use. So nothing new here.
The trouble is with very low frequiency communications is at low frequencies the wavelength is very long, therefore you have to have very large antennas that are very low in efficiency.
When in the military, I used to maintain a 250Kw LF transmitter, (around 44Khz) for submarine communications, the antenna was housed (mounted) on 3 x 800 foot towers, and that was only for the capactive 'top hat' for increased radiation efficiency. But
to do low frequency comms, you need high power, large antennas, and low bandwidth. And low information rates.
So it's nothing new, it's been done and for a very long time.