10 ms·
ADSL over wet string
- AdmiralAsshat 9y agoIntroducing: Verizon's post-net-neutrality definition of Broadband-ready "fiber" lines.
- discreditable 9y agoNew plan to replace aging copper networks.
- zingermc 9y agoUpgrade your business infrastructure to SaltyTwine™ today!
- hinkley 9y agoWhat kind of aggregate bandwidth can I expect from my network fabric?
- emmatoday 9y agoUpgrade to organic fiber today! Only $20 more per month!
- macawfish 9y ago"He got some proper string, and made it wet..."
- macawfish 9y agoidk what people thought i was alluding to here, i just thought it was a fun/funny way to talk about the experimental setup. get your minds out of the gutter!
- moultano 9y agoAnyone have a link that explains (ideally with some math) how this works?
- nathancahill 9y agoString wet with salt water conducts electricity similarly to wire.
- moultano 9y agoI was curious about this line in particular. > One of the key aspects of the technology is its ability to adapt to the length and characteristics of the line on which it is deployed.
- herpderperator 9y agoDSL transfers data over specific frequencies. Certain frequencies will resonate better than others over certain lines. Here is an image of a line test conducted for a VDSL2 customer: http://wut.nz/images/spm/1027296.jpg http://wut.nz/images/spm/1027296.jpg. The redder the graph, the faster (up to the maximum VDSL2 speed) the connection is. The vertical line is when the connection spontaneously resynced, and a new speed was attained based on the new conditions of the line. For this particular customer, you can see that tones 410-460 show no transfer at all. This causes a reduction in speed, since those frequencies couldn't be used.
- mordechai9000 9y agohttps://en.wikipedia.org/wiki/Asymmetric_digital_subscriber_line#Operation https://en.wikipedia.org/wiki/Asymmetric_digital_subscriber_... https://en.wikipedia.org/wiki/Reed%E2%80%93Solomon_error_correction https://en.wikipedia.org/wiki/Reed%E2%80%93Solomon_error_cor... As I understand it, the endpoints test a range of frequency blocks (or "bins") and only use the ones where there is sufficient signal-to-noise. This is dependent on line conditions.
- outworlder 9y agoHeh, "line". That has a very different connotation in this case.
- circlingthesun 9y ago"As a bonus, fit tin cans to both ends and you get voice as well as broadband on the same wet string!" Ha!
- nathancahill 9y agoNot sure if science or another pro net neutrality piece.
- eropple 9y agoI linked this to my dad (who's been a network engineer and CIO-type for nearly thirty years) and his response kind of floored me: "yeah, we did this with ARCNET. Brine-soaked twine." So, one, this is Older Than It Looks, and two, apparently my dad might be a wizard?
- jurjenh 9y agoAlso reminds me of ethernet over barbed wire. Seems like similar things have been done for a long time... http://www.sigcon.com/Pubs/edn/SoGoodBarbedWire.htm http://www.sigcon.com/Pubs/edn/SoGoodBarbedWire.htm
- roywiggins 9y agoA long time! https://www.atlasobscura.com/articles/barbed-wire-telephone-lines-homesteaders-prairie-america-history https://www.atlasobscura.com/articles/barbed-wire-telephone-...
- softawre 9y agoMan, I wish my dad was technical. Treasure that relationship.
- Waterluvian 9y agoMy dad did CS in the 70s then got into sales. So our tech talks usually go right to, "do your languages do recursion? That was a big deal when I was doing Cobol on UW's PDP8" or something along those lines. Always with the recursion.
- StavrosK 9y ago"Does this conversation?"
- bwann 9y agoI've often wondered if Ethernet can be ran over brine or wet string, if even only just a few inches. I played with the idea once unsuccessfully but never put more than five minutes into it.
- scrollaway 9y agoFor context, this is Adrian Kennard's blog. He's the CEO of AAISP (which I'd highly recommend for UK residents, they're extremely ethical and transparent; although I would not recommend their mobile service for different reasons).
- jstanley 9y agoI recently switched to AA from Virgin Media due to the unreliability of Virgin's service, but have found AA's to be no improvement. I currently subscribe to both services and toggle back and forth whenever one of them stops working. I recommend AA for their philosophy, and the debugging tools in their web interface are second to none, but in my brief experience the quality of their actual service is no better than anyone else's.
- nalllar 9y agoIf you're seeing frequent drops in connection, contact their support. [0] They're very good at getting openreach to fix problems. Another option for you in particular (if you're willing to keep paying for both virgin and AAISP) is to set up a router with multi-WAN support which can load balance between both wans and handle failures, instead of swapping manually. [0]: http://aa.net.uk/support.html http://aa.net.uk/support.html
- y4mi 9y agoYou probably already know this, but I think it should be pointed out for others: this is not a true fail-over. The connection still gets dropped and needs to be reestablished. So, an online game will disconnect and a video stream will stop. You will however be able to reconnect or refresh right away.
- blibble 9y agoAA provide true fail-over if you buy multiple lines from them with different backhaul providers, and have a separate solution that will provide true fail-over with lines from other ISPs(!!) I had it for 2 odd years: you get a few dropped packets before the system realises a line has become unavailable if it hadn't been for the email telling me I'd never have noticed that a line dropped: connections remained established and downloads continued (at a lower speed)
- lb1lf 9y agoYears ago, I tried the same thing on ham radio - made an antenna from a piece of wet string and tried to call cq. It worked a charm, though I had to continously wetten the string as I applied RF power to it. (21MHz ground plane antenna; eased the top end of the string through a hole pierced in an empty beer can, suspended it from a tree and filled the can with salt water. Losses were huge, so antenna was easy to tune. Not the best of radiators, though, but I did work twelve or thirteen countries with it. Cost of string and beer - $4. "Antenna this end is the proverbial piece of wet string - literally. Back to you." -Priceless.
- TeMPOraL 9y agoJust got my HAM license and callsign. Gonna try this out.
- lb1lf 9y agoJust make sure not to use too much power - ten watts is plenty to start with. Oh, and congratulations. You're in for a treat. (Though I would suggest not using wet string as your only antenna. :-)) 73 de LB1LF /OddE
- vvanders 9y agoI've used some pretty dicey end-fed half waves but that takes the cake! Probably harder now that we're in a solar minimum but you'd have decent luck on CW.
- SagelyGuru 9y ago
- UseStrict 9y agoTake a net, dip it in water, boom! Mesh networking.
- wyldfire 9y agoYou're joking, but that was the first application I thought of. It would be really interesting to create a low-throughput fallback network for neighborhoods using something like this. Though I suppose RF or optical are still quite a bit more practical.
- topranks 9y agoOr copper. You'll never justify your choice of "wet string" as medium of choice when things go south.
- grandalf 9y agoI wish more science were taught using this kind of thing as a starting demo to provoke a lot of wonderment.
- Negitivefrags 9y agoI once had an issue where my phone line was completely dead, but I was still getting ADSL, just at very slow speeds. In the order of 1mbit. After the technician came he told me that one of the two phone line wires had been broken off at the exchange. In other words, there wasn't a complete electrical circuit. The phone was dead but ADSL still works without even having a complete circuit. I don't even understand how that can work at all.
- nomel 9y agoEverything about a POTS operates completely from DC to audio band, from the DTMF tones [1] when you press a number to the signal that makes the phone ring (~90V@25Hz AC) [2], to the -48VDC power that makes the keypad light up and any electronics operate, backed up by massive battery banks and generators, in case of power outage. ADSL operates completely beyond the audio band[2]. Since it's entirely a high frequency AC signal, with no DC component whatsoever, a break in a wire will just act as a capacitor, reducing the AC signal strength. Since a broken wire is a terrible capacitor, the signal strength will be reduced tremendously, but in your case, not enough to drop the link. [1] http://www.etsi.org/deliver/etsi_es/201200_201299/20123502/01.01.01_60/es_20123502v010101p.pdf http://www.etsi.org/deliver/etsi_es/201200_201299/20123502/0... [2] https://en.wikipedia.org/wiki/Asymmetric_digital_subscriber_line#/media/File:ADSL_spectrum_Fritz_Box_Fon_WLAN.png https://en.wikipedia.org/wiki/Asymmetric_digital_subscriber_...
- Mister_X 9y agoHmm, should have read your post first... Thanks for the more detailed explanation, and with that, my guess above, is on the money, interesting communication tech.
- nomel 9y agoThe most fascinating thing about any of these high-speed-over-crappy-wire technologies is that they all have very cool signal processing going on, with echo cancellation, crosstalk compensation, and even trading of signal response, all in an effort to design and transmit a sort of "anti distortion" distorted signal that, once passed through the distortion caused by the crappy wire, will results in the desired clean signal. For a funny example of how sensitive some of these links are, just flick a 100m ethernet cable, running at 10G, with your finger. If you're of normal luck, this will cause a temporary changed in the electrical characteristics of the wire, and that "anti distortion" distortion to be temporarily incorrect, causing a interruption in the data!
- korethr 9y agoSo, now that the concept has been proven, are we going to see a proper RFC proposal to standardize this? There's still 110 days left for submissions. That should be plenty of time to test what string types and electrolytes work best for various applications, to and improve the distance limit.
- runeks 9y agoAfter another 10 ADSL iterations, I think someone will accidentally forget to connect the wires and discover that it works just fine over the air.
- jwfxpr 9y agoBroadband without wires? Preposterous.
- jschwartzi 9y agoYeah, how would we charge money for it?
- zkms 9y agoYou kid but this is literally what is being proposed in industry conferences: https://www.assia-inc.com/wp-content/uploads/2017/05/TDSL-presentation.pdf https://www.assia-inc.com/wp-content/uploads/2017/05/TDSL-pr... -- sending ~200GHz [sic] RF into the dielectric spaces between copper conductors and using the copper wires as guide (same principle as Sommerfeld-Goubau lines, except massively MIMO). (the same principle is also quite interesting to apply to above-ground power lines, btw, people have worked on that too) People will do literally anything to avoid pulling fibre and "sending multi-hundred-gigahertz surface waves along rotten old voice copper" is apparently one of them.
- ClassyJacket 9y agoI'm sure Australia's NBN will add this to their 'multi technology' mix any day now.
- King-Aaron 9y agoEvery time it rains, my local copper pit fills with water and my internet drops out. Maybe they should replace the copper with Damp Twine to the Node.
- lerie82 9y ago"salty wet twisted pair", lovely.
- toomanybeersies 9y agoHot dogs are also conductive, since they are also filled with salt water. I wonder if you could do ADSL-over-hotdog. Obviously the length would be limited by the length of a frankfurter, so you wouldn't be able to get more than a foot or so, but it would be an interesting experiment. A pickle might work too.
- gonzo 9y agoI once did this with HPNA 1.0
- Humphrey 9y agoPerhaps some Australian NBN (National Broadband Network) customers would get improved speeds with wet string over their fibre to the node installations