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ADSL works over wet string (2017)

Author: mgliwka

Score: 332

Comments: 109

Date: 2021-12-04 13:25:26

Web Link

________________________________________________________________________________

giardini wrote at 2021-12-04 15:21:56:

ADSL, being essentially a form of alternating current, will pass through an air gap. I was enlightened on this by an AT&T tech who pointed out that one of my ADSL lines had several breaks and could not carry DC but the ADSL signal still came through. The other line was dead so I was running essentially on one wire with an earth ground. Here is an interesting discussion:

"Phone line with 1 broken wire still gets ADSL2"

https://forums.whirlpool.net.au/archive/9yzp5wr3

Anyway, my hat is off to the people who designed and implemented ADSL.

DaiPlusPlus wrote at 2021-12-04 16:32:32:

> Anyway, my hat is off to the people who designed and implemented ADSL.

It's a blessing-and-a-curse: too many incumbent ISPs in highly-developed nations used ADSL's ability to run on anything as an excuse to put-off FTTH deployments (looking at you, BT).

samwillis wrote at 2021-12-04 17:23:46:

I think we (in Stamford Lincolnshire, UK) must be pretty unique right now with TWO competing FTTP startups both rolling out on the same streets. One day you will see Lightspeed Broadband pulling their fibre through the BT ducts and putting boxes on the top of telegraph polls. The next day Upp Brordband will be on the same street. So bizarre they they are doing the same town!

Apparently we are due to have BT put in their own fibre in the next few months too. Really don’t understand why they are doubling up the infrastructure.

Hoping for a local price war!

martinald wrote at 2021-12-04 19:50:21:

Basically there is an enormous amount of capital (at least ÂŁ10bn from startup providers) out there going into UK FTTH builds. BT focussed too much of content (BT Sport) instead of FTTH and private equity now thinks there is an opp to steal marketshare from BT/VM.

However BT have now now committed ÂŁ10-20bn, VM probably a few billion.

It will quickly consolidate like it always does.

samwillis wrote at 2021-12-04 22:25:55:

Thanks, I figured it was something like that. One of the startups here is a bunch of former BT execs so I was assuming they were hoping to exit by selling either to BT or VM.

rconti wrote at 2021-12-04 17:53:06:

Very strange! Mine was not quite as happy a story, but here in Silicon Valley (1mi from Facebook) I got a local ISP announcing fiber, and the very next week AT&T was running their own lines. This was back in 2019, and it felt like "everyone" had fiber before we did. 2 years later I guess it feels like old hat. And the local ISP has not yet run the fiber they promised. But one fast ISP is better than zero!

Good luck with your deployment. I'm still so happy about it.

mattlondon wrote at 2021-12-04 20:25:02:

Here in high-density London, we're stuck with ~70mbps ADSL and not even cable.

Not representative of all of London, but at least around my parts it is slow ADSL or nothing :(

charcircuit wrote at 2021-12-04 22:17:03:

Are you suggesting 70Mbps is slow ADSL? There are many places where not even a tenth of that speed is possible.

867-5309 wrote at 2021-12-04 22:25:44:

it's the UK average for urban ADSL. and those many places are where the FTTH startups are springing up

aphrax wrote at 2021-12-04 17:29:05:

How strange to see my hometown mentioned! Still not too far away and yes hoping for some local competition

unixhero wrote at 2021-12-04 19:04:18:

Telenor

They also did the same, stalling and delaying, insisting on introducing ISDN 64/128kbit instead of going straight to DSL like Holland did.

ohyeshedid wrote at 2021-12-04 19:52:19:

From previous personal experience in building new plants, and expanding existing plants: Cost of deployment and slow roi are the primary drivers of stagnating local networks.

Complicated corporate accounting, carrier incumbency, and weak governments are the core causes. Carriers being publicly traded companies really screws up incentives to fix these problems. It seems to be mostly a binary decision at the top; more profit or better service?

kazen44 wrote at 2021-12-04 20:56:53:

also, the infra (which ADSL runs on) was build in a time when telephone companies used to be either state-owned or a single monopoly with heavy goverment involvement.

Doing the same thing with fiber is necessary, but will not happen without strong govermental involvement.

verve_rat wrote at 2021-12-04 22:49:49:

Indeed. New Zealand has had a pretty successful fiber roll out over the last several years because the government awarded exclusive contracts to fiber providers that then have to provide access to their network to all ISPs.

Works great. Even my village of several hundred people has fiber now.

samstave wrote at 2021-12-04 17:57:24:

>>...*my hat is off to the people who designed and implemented ADSL.*

Maybe a few will recall: San Jose California, in the epicenter of Silicon Valley -- but for some reason Comcast (was previously called *_COVID*_) -- and you couldnt get DSL in San Jose at the time .... literally down the street from Netflix, and freaking home DSL took YEARS for it to reach our houses...

(My point is that it was ironic that in the heart of silicon valley we couldnt even get DSL due to COVID/Comcast

toast0 wrote at 2021-12-04 18:19:34:

Are you thinking of COVAD? IIRC, they were a competitive local exchange carrier, unrelated to Comcast.

As a CLEC, they could place DSL equipment in the incumbent carriers (mostly Pacific Bell/ATT, but Los Gatos Telephone company was absorbed by GTE/Verizon and I think sold to Frontier) and use the existing wiring to run DSL. In silicon valley, this doesn't offer great coverage; to get reasonable line lengths, you need to be in the telephone company's remote terminals and that's not available to CLECs.

hungryforcodes wrote at 2021-12-04 18:16:04:

Meh

zaphirplane wrote at 2021-12-04 21:10:30:

In hind sight wouldn’t 5g have been a better investment than fiber to home, I mean companies will have to have 5g to stay competitive in mobile anyway

tiernano wrote at 2021-12-04 17:25:18:

this explains a problem i had in Ireland... ADSL worked, but phone line had to dial tone... engineer had no idea how it was working... mind you, ISP had sent him out to get better internet... i was on 8mb and was promised closer to 24... after he "fixed" it, it went to 6... so they were really not happy with the "engineer" when i canceled 2 days later...

Terry_Roll wrote at 2021-12-04 18:43:31:

Its DC. If you had to imagine it, think of it as a range of radio stations being broadcast down a wire instead of over the air and your router can tune in to all the radio stations at the same time and then piece together the different bits of data being broadcast.

Long Wave would be ADSL, ADSL2, Medium Wave ADSL2+, and FM would be higher forms of ADSL to give you your 40Mb, 80Mb, 100Mb download speeds.

With this broadcasting of signals down a wire now known, it becomes somewhat unsurprising anything capable of transmitting an electrical voltage & current would be capable of transmitting ADSL. Not knocking their effort though, Arnold and Arnold have always like to demonstrate their knowledge. One of them has a personal blog which can be quite interesting.

I wonder if they have considered trying to adapt an SDR dongle to become an ADSL transmitter?

hereforphone wrote at 2021-12-04 18:54:34:

What's DC? "Radio stations" communicate via alternating quantities (EM waves)

Terry_Roll wrote at 2021-12-04 20:49:22:

The telephone cable coming into the house is 50volts DC is not AC like a powerline. I know radio waves are just that, waves, its how things like noise cancelling headphones work. Different frequency's give you different ranges or distances for 1 watt, which is why you can bounce Long wave around the planet.

leoedin wrote at 2021-12-04 21:22:43:

Radio waves down a wire are by definition AC. Otherwise they don't work. The voltage must change, thus the current must change, thus it is AC. Just because it's not 50/60Hz AC like a powerline doesn't change that.

There might be a DC component, but ultimately all the ADSL modem cares about is the AC part.

Terry_Roll wrote at 2021-12-04 21:56:31:

I wasnt taught that radio waves were to be considered identical to AC power down a cable but when thinking about it, they probably are identical with waveform properties and the difference being the medium they are travelling through.

hereforphone wrote at 2021-12-04 21:01:19:

48VDC but yes. Sounds like we're agreed that the information is being transmitted via AC or another alternating signal.

geofft wrote at 2021-12-04 16:27:04:

In some sense, that's "just" radio. An antenna is a wire... it's sending a signal and picking it up from a very nearby antenna. Radio transmissions are all AC.

(Arguably, the real insight here is that the very existence of radio is impressive / unintuitive.)

y04nn wrote at 2021-12-04 17:35:53:

The gap on the line acts more as a capacitor than an antenna, AC pass through capacitors, but DC does not.

andoma wrote at 2021-12-04 17:27:02:

Same thing happened once at my parents house. Quite confusing for some :)

robinduckett wrote at 2021-12-04 23:01:44:

These guys are my ISP they're wonderful

codeflo wrote at 2021-12-04 14:11:38:

That fact that this delivers 3.5 MBit/s really makes you wonder how many low speed connections out in the wild are literally broken cables that still have some amount of coupling somewhere.

pteraspidomorph wrote at 2021-12-04 15:01:33:

I lived in a forested area as a kid and the copper wire was always breaking for various reasons (falling branches, old deployment, temperature and humidity, etc). The ISP would always attempt to reduce the speed and leave it at that. It took a lot of effort as well as personally locating the breakage to get them to come and repair it properly (and it still took forever).

someperson wrote at 2021-12-04 14:29:11:

Potentially apocryphal, but Telstra's copper cable network supposedly had its insulation made of paper, not rubber. I remember when it rained the curbside pits fill with water, causing slowdowns and frequent ADSL dropouts (until things dried out).

kabdib wrote at 2021-12-04 16:48:38:

It took over a year for Ziply to repair the land line of my 90-year-old parents. 30+ hours on the phone with support, multiple visits by techs who were simply not interested in doing any work. I had a tech tell me, literally to my face, "this line is working fine" when the line was stone dead. Another told me that I had to buy all new phones because the ones my parents had were "out of date". (To humor him, I bought a $15 phone from a local electronics store, plugged it in and showed the tech that it wasn't working. He did nothing).

I have now learned that the WA state utilities commission is pretty interested when providers try to pull stunts like this. You can also dig out useful company contact information from the commission's website.

rootusrootus wrote at 2021-12-04 17:45:44:

> I have now learned that the WA state utilities commission is pretty interested when providers try to pull stunts like this.

A number of years ago I worked at a CLEC, during that short window of time when they could exist. One of the more useful things I learned is how much power the PUC has. Every phone company has a team that deals with complaints coming in via the PUC and they are eager to resolve them. Not something I'd necessarily use in lieu of regular old customer service for most issues, but when the first and second attempts fail, calling the PUC will work 100% of the time.

xattt wrote at 2021-12-04 17:03:42:

Many parts of rural Prince Edward Island (PEI) has DSL running on a phone system that’s probably original from modernization initiatives in the 1960s - 1980s. Party lines were the norm in some areas up west until late-1980s.

spookthesunset wrote at 2021-12-04 20:03:53:

Back when a whole family had the same number and you had to ask whoever answered that you want to talk to so and so. Now days everybody has their own number and with caller id you (sometimes) know who is calling.

My daughter is gonna grow up not knowing any of the “shared phone line” etiquette because it is largely obsolete.

xattt wrote at 2021-12-04 21:24:15:

The party lines I’m talking about are shared loops between a group of residents in a rural area.

Some of the first-hand accounts I’ve read talked about neighbours listening in on conversations. People could tell a snooper was on the line because the volume of the other caller would drop. There was a social aspect to the whole enterprise because you could tell the one nosy neighbour to get off the line and the volume would magically raise.

(1)

http://www.islandregister.com/phones/partyline.html

kube-system wrote at 2021-12-04 21:16:03:

A party line is not when "a" whole family shares a line, it's when several separate houses share a line.

Finkregh wrote at 2021-12-04 18:31:21:

You spelled Germany wrong... X_x

tenebrisalietum wrote at 2021-12-04 15:03:55:

I think this is common in places where they don't expect moisture to reach, but then things change and it gets there anyway.

If your POTS lines are down and the telecom company is telling you a "wet pulp repair" is underway, your phones are going to be down for a while because a bunch of paper-insulated cables need to be manually rewired because they got wet and corroded.

I found this interesting:

http://etler.com/docs/bsp-archive/629/629-295-300_I3.pdf

- guess it's standard practice to dry out the lines, wrap in cloth, put dessicant and then seal it.

jcims wrote at 2021-12-04 15:40:48:

I know there are some telecom folks on here that may be provoked to correct me but pulp was standard before the advent of cheap plastic insulation in the 1950s on up. I live in the midwest and my brother is a lineman for AT&T. There is an astonishing amount of pulp-insulated phone line still in service today.

In order to keep it dry, the conduit that the pulp lines are run through is pressurized to 5-10psi. Anyone that has worked with air compressors knows that pumping ambient pressurized air down into underground pipes is a recipe for condensation, so high capacity air driers are required to remove the water before it goes underground.

Any kind of outage on the compressor or dryer is effectively an emergency because water infiltration can happen almost immediately, creating an outage and extremely expensive repair.

ComputerGuru wrote at 2021-12-04 16:24:24:

> I know there are some telecom folks on here that may be provoked to correct me

Aka Cunningham’s law

> Any kind of outage on the compressor or dryer

I’m confused: isn’t a bigger concern any physical damage to the conduit anywhere in the run that is too large for the compressor to overcome? Or are we talking football-field-sized compressors here?

BoorishBears wrote at 2021-12-04 16:44:48:

http://www.airtalk.com/z_ref-4_1.html

stefan_ wrote at 2021-12-04 18:27:39:

The more you learn about this ancient cable technology the more absurd it becomes. We shower these fuckers with money but they would rather keep their _paper insulated phone lines with permanent compressors and dryer running_ than braindead simple fiber. No wonder it is permanently broken and they can't keep a single 9 of reliability.

oasisbob wrote at 2021-12-04 19:30:44:

Fiber may be simple, but the way we use it is not. Unlike copper, a GPON fiber install is going to have active electronics and splice trays for every several dozen subscribers.

Plenty of opportunities for water ingress to still cause problems.

kazen44 wrote at 2021-12-04 21:01:22:

Also, sending a singal across fiber is definitely not easy.

ADSL is basically modulating a radio wave over a cable directly to another device.

Fiber requires high quality optics, high quality lasers, tons of active hardware if you want to do it at scale. (not to mention the mind boggling physics and manufacturing required for things like DWDM, optical path switching etc).

Fiber optics have existed since the 80's yes, but prices of high quality fiber solutions have only dropped massively in the last decade or so.

stefan_ wrote at 2021-12-04 21:10:14:

Exactly. That all sounds infinitely easier than buried air pipes. Mind boggling physics are what gives us CPUs, but the final product is reliable bar none.

NavinF wrote at 2021-12-04 21:10:43:

Meh. Fiber has been cheaper than copper per mile for a long time and 10km optics are like $20.

jcims wrote at 2021-12-04 18:31:13:

I would bet this is a capex/opex thing.

whalesalad wrote at 2021-12-04 14:20:50:

Sums up my youth on ADSL in the hills of LA. Couldn't get a static IP address on coax/cable so I convinced my family to pay out the ears for speakeasy.net DSL w/ a static IP. Performance was terrible!

mbreese wrote at 2021-12-04 16:08:58:

I had a bonded DSL line for a while when I lived in the Bay Area with service coming from two different twisted pair lines. One line was consistently ~18Mbps, the other barely 3-5. It was pretty clear that one of the pairs was good and the other was broken somewhere alone the way. The lines were all in a bundle, with no way to discern what was what any individual strand was in the bundle (or which was broken or shorted). No one had any motivation to find the break and repair it. And because the line was technically “working”, ATT wouldn’t move it to a different pair. Sonic was the ISP with ATT handling the physical lines.

Still amazing that it worked at all.

londons_explore wrote at 2021-12-04 16:21:26:

You can do time domain reflectometry to find out where the breaks, sharp corners and reflections are in the cable.

Some modems have special debug modes in that can do this too - then you get to know exactly how many meters along the wire the break is. When you get close, you can hook a resistor to the line and rerun the test and it'll tell you how many meters forward or back you need to go to find the issue.

Pretty easy to track issues down that way.

mbreese wrote at 2021-12-04 16:36:36:

Yeah, this was in a neighborhood bundle with many… many lines together. No one was going to dig into that to find which line a mouse or squirrel had chewed the insulation off of. I remember running a few diagnostics, but as it was “working”, no one was going to try to fix it. The ISP couldn’t even convince ATT to move the bad line to a different pair. Which was sad. I was supposed to be in the 40Mbps range, but could only get ~18-20. Also — this was enough bandwidth for us at the time, so I just ran off of the single line and was good. Given some of the dsl horror stories, we weren’t too and off.

ajsnigrutin wrote at 2021-12-04 15:54:21:

A lot of the problem lies with distance.

10km of fiber (with transcievers made for that kind of fiber and distance)... gigabits without any issues.

10km of copper pairs for *dsl? Good luck.

fghorow wrote at 2021-12-04 14:18:37:

Wet string? OK, fine.

But I defy ADSL to work over something really challenging. Like Telstra copper in Australia.

hedora wrote at 2021-12-04 15:27:00:

You think the outback’s bad? Try getting it to work over AT&T copper in heart of Silicon Valley!

Faaak wrote at 2021-12-04 14:43:47:

Related: ethernet over barbed wire:

http://www.sigcon.com/Pubs/edn/SoGoodBarbedWire.htm

throw0101a wrote at 2021-12-04 17:45:33:

There are IEEE standards for single-pair Ethernet:

> _In addition to the more computer-oriented two and four-pair variants, the 10BASE-T1,[17] 100BASE-T1[18] and 1000BASE-T1[19] single-pair Ethernet physical layers are intended for industrial and automotive applications[20] or as optional data channels in other interconnect applications.[21] The single pair operates at full duplex and has a maximum reach of 15 m or 49 ft (100BASE-T1, 1000BASE-T1 link segment type A) or up to 40 m or 130 ft (1000BASE-T1 link segment type B) with up to four in-line connectors. Both physical layers require a balanced twisted pair with an impedance of 100 Ω. The cable must be capable of transmitting 600 MHz for 1000BASE-T1 and 66 MHz for 100BASE-T1. 2.5 Gb/s, 5 Gb/s, and 10 Gb/s over a 15 m single pair is standardized in 802.3ch-2020.[22] As of 2021, the P802.3cy Task Force is examining having 25, 50, 100 Gb/s speeds at lengths up to 11 m.[23]_

*

https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair#Sin...

Including power delivery:

> _The IEEE 802.3bu-2016[12] amendment introduced single-pair Power over Data Lines (PoDL) for the single-pair Ethernet standards 100BASE-T1 and 1000BASE-T1 intended for automotive and industrial applications.[13] On the two-pair or four-pair standards, power is transmitted only between pairs, so that within each pair there is no voltage present other than that representing the transmitted data. With single-pair Ethernet, power is transmitted in parallel to the data. PoDL initially defined ten power classes, ranging from 0.5 to 50 W (at PD)._

> _Subsequently, PoDL was added to the single-pair variants 10BASE-T1,[14] 2.5GBASE-T1, 5GBASE-T1, and 10GBASE-T1[15] and as of 2021 includes a total of 15 power classes with additional intermediate voltage and power levels.[14]_

*

https://en.wikipedia.org/wiki/Power_over_Ethernet#PoDL

toast0 wrote at 2021-12-04 18:30:07:

Sadly, there's not much in the way of equipment for this. I could really use two small 10BaseT-1 to 10BaseT converters, preferably both powered from one end.

throw0101a wrote at 2021-12-04 18:41:57:

Seems to be mostly in the automative and industrial space, with some embedded stuff.

I could also see it being useful for door security (badge readers, latch control).

toast0 wrote at 2021-12-04 18:51:42:

For me, I've got a gate with a keypad. It's got an ethernet port, but they only ran 3 pair to it, and it works best with 2 pair for voice communications, so I've only got one pair for data, not enough to use.

WaitWaitWha wrote at 2021-12-04 17:23:17:

I remember in the 90s when we were deploying a business campus, we first used ADSL services from the local carrier, but not for long.

We discovered we can get "dry lines", basically just rent copper run from site-to-site, nothing on it from local carrier. Slap ADSL modems on each and we got max throughout, at a fraction of the cost. Then we upgraded to SDSL, and that was like hitting the jackpot.

techdragon wrote at 2021-12-04 20:53:23:

I’ll go one better, ADSL doesn’t even need two continuous wires to work, one is good enough as long as the other is just barely electrically coupled. I had a 12 month epic journey to get a performance fault fixed on my line. In the end it took 6 technician visits, three senior technicians and finally one smart experienced technician to check the “not in the textbook” faults for a performance degradation and he discovered that my line had was actually mis-wired! I had one wire connected to the exchange and another was a barely connected lose joint (actually disconnected but still technically in the plastic joint housing) about half way to the exchange. I was still getting a few megabits with intermittent drop outs for months on what amounted to a single wire!

sdflhasjd wrote at 2021-12-04 14:02:10:

3.5Mbit!? Says a lot about my parents paltry 1Mbit. Perhaps their line was low on sodium.

tyingq wrote at 2021-12-04 15:00:17:

The cable analyzer is showing about 55db of loss across 2 meters. That's about equivalent to the loss across 4km of "good" copper.

sdflhasjd wrote at 2021-12-04 16:22:32:

I kid, the issue was solved some time ago - a telecom engineer pinned it down to a soggy junction box.

SV_BubbleTime wrote at 2021-12-04 16:53:00:

That’s funny because my SO’s parents have 1.5Mbps DSL by contract. For only $100/mo they can jump up to 12Mbps. USA and 1 hour from me where I have gigabit docsis 3.1.

If they had 1Mbps because of a fault that would be more unfortunate than unfair.

iso1631 wrote at 2021-12-04 14:30:58:

3.5mbit over 2 metres

cunthorpe wrote at 2021-12-04 16:31:36:

Your parents’ ADSL noodle soup is a little bland.

derefr wrote at 2021-12-04 15:55:01:

Can ADSL survive an acoustic coupler?

To give it a fair shot, assume the driver and microphone are studio quality rather than the kind you’d find on a 1970s telephone handset. I bet it’d work pretty well.

But the real question would then be: how much of an air gap could you create and still get a connection?

Could you post to HN on an ADSL signal that’s being screamed across the length of the room you’re sitting in?

detaro wrote at 2021-12-04 15:58:21:

ADSL upstream _starts_ at 25kHz, downstream at >120kHz. So probably not. Purpose-designed ultrasonic hardware might be able to.

codeflo wrote at 2021-12-04 17:01:14:

Not sure if this is within the spirit of the question, but: The individual ADSL bands are only 4 kHz wide, so you could modulate 4 or 5 of them down into the audible range (20Hz - 20kHz) and back up again after the transmission through the acoustic coupler. In theory, ADSL should then pick those bands to transmit the data.

londons_explore wrote at 2021-12-04 16:25:29:

Or an acoustic coupler which also acts a little like an electrical coupler at higher frequencies because it has no electrical shielding...

qeternity wrote at 2021-12-04 16:56:49:

This thread is a good reminder to be very thankful for my ÂŁ20/month unmetered 1gbit central London FTTH.

dang wrote at 2021-12-04 17:12:17:

Discussed at the time:

_ADSL over wet string_ -

https://news.ycombinator.com/item?id=15908107

- Dec 2017 (88 comments)

Eduard wrote at 2021-12-04 14:55:23:

Our homes' water supplies are untapped options for data connectivity.

joncrocks wrote at 2021-12-04 15:28:09:

joking aside, I remember a while back that there has at least been cursory investigation into running high-speed internet cables through water pipes.

Presuming you have water pipes to your property, could be easier than digging up roads etc.

Only issue might be if you have a leak and need to shut off your water!!

https://www.theguardian.com/technology/2021/aug/09/uk-launch...

ixfo wrote at 2021-12-04 16:50:49:

The linked article (and government push to do this) completely ignores the fact that this is done frequently now.

It's used to get the last few metres into the home, e.g. from the boundary to the inside of the house. You put a swept tee in at each end, _after the stopcock_. Water off, dig down adjacent to stopcock, cut pipe, shove a drinking water rated duct down the pipe through the small port on a swept tee. Shove some chlorine tablets in the pipe and couple up to the new swept tee. Repeat interception at other end outside or indoors, and then use standard fibre cable blowing through the inner microduct, and away you go.

There's a huge amount of disused water pipes in most developed nations which are frequently used, similarly using sub-ducting, and you can run cable through mains - but have to come out every time there's a valve, so practically it's usually cheaper to dig. Where it comes in handy is where there's areas you can't practically dig up, e.g. major roads with old pipes underneath.

Source: Have done a bunch of this for a major UK telco.

https://www.craley.com/craley-in-pipe-fibre

DaiPlusPlus wrote at 2021-12-04 16:33:57:

> I remember a while back that there has at least been cursory investigation into running high-speed internet cables through water pipes.

Oblig:

https://archive.google.com/tisp/index.html

https://archive.google.com/tisp/install.html

Suchos wrote at 2021-12-04 16:26:24:

There is company in Czechia which provides optics via sewage. I guess it is cheaper to use existing infrastructure than to place new pipes under roads.

martyvis wrote at 2021-12-04 21:31:10:

Sounds a bit like this "How TiSP Works"

https://archive.google.com/tisp/install.html

hereforphone wrote at 2021-12-04 21:00:21:

I think this relies on the particular string being a linear time-invariant channel. There is some limit where the string won't react accordingly (at a certain low or high frequency). What is that later phenomenon called, anyone know?

NavinF wrote at 2021-12-04 21:04:18:

Hmm the author had to use salt water to get it working. Maybe resistance is the limiting factor rather than dispersion. In which case a higher power modem or some sort of amplifier would get this working over >2m distances.

agumonkey wrote at 2021-12-04 14:00:40:

Since seeing this article I've been curious about organic conductors .. apparently most carbohydrates / celluloses are really not good basis for conduction but maybe there are tricks to change that.

-

https://www.quora.com/Is-cellulose-fibre-conductive?share=1

-

https://duckduckgo.com/?t=ffab&q=conducting+polymers+example...

sdflhasjd wrote at 2021-12-04 14:51:32:

Paper and cotton were both used in cable insulation in ye olden days, impregnated with oils and tars

hammock wrote at 2021-12-04 17:25:16:

What do they use now?

rahimiali wrote at 2021-12-04 18:18:30:

Conductive polymers are commonly used these days. Pedot:pss can be engineered expressly this way, but less exotic ones like polyamides can do this too.

hashimotonomora wrote at 2021-12-04 14:33:09:

Essentially you need loose electrons to conduct.

VHRanger wrote at 2021-12-04 14:45:52:

That's not exactly correct. Electrons don't flow through wires - there's a one-way flow of the ambient electrons around the wire from the field created.

See here:

https://www.youtube.com/watch?v=bHIhgxav9LY

hashimotonomora wrote at 2021-12-04 15:13:39:

That video is misleading. Electrons must be relatively loose in their orbitals in order for the electromagnetic field to be established with reasonable strength. This does not mean that electricity is the literal flow of electrons. However, electrons actually do flow at a speed of about 1 mm/min due to the electrostatic field in DC circuits. This is not what’s called electricity but they do flow.

NovemberWhiskey wrote at 2021-12-04 16:02:09:

You're confusing the electrons and the electromagnetic fields. The electrons absolutely do migrate through the wires; the electric field does not. P.S. that video appears to have been written to confuse/generate controversy and does a terrible job of actually explaining.

SV_BubbleTime wrote at 2021-12-04 18:41:07:

> The electrons absolutely do migrate through the wires;

That’s true. But very slowly in electrical terms. If I remember right the actual electronics in a reasonable circuit I read about was something like 1” per second. The vast majority of work done is an electron shuffle of bouncing into the next one in space.

NovemberWhiskey wrote at 2021-12-04 18:51:09:

When you say "work", what do you mean? I get the impression you're talking about a model like there's a long tube full of ball-bearings and when you push one in, one drops out the other end?

That model isn't right; think about a transformer - energy is transferred between conductors that are not physically connected at all.

pjc50 wrote at 2021-12-04 15:18:56:

Well .. they do flow _in_ the conductor, and in particular they flow through silicon junctions or none of the semiconductor physics would make sense, but the energy is carried in the field which is indeed outside the conductor.

agumonkey wrote at 2021-12-04 14:51:16:

But maybe you could have different organic crystalline structures allowing AC currents to flow. Wildly speculating of course.. I was just hoping to tape in forest materials to manufacture low power electric devices :)

pjc50 wrote at 2021-12-04 15:20:16:

Graphite counts; if you want to manufacture it from forest materials, compressed bonded charcoal might work.

https://www.sciencedirect.com/science/article/abs/pii/S01675...

agumonkey wrote at 2021-12-04 15:25:15:

True but its resistance might be too high maybe ? also it's not easy to make graphite.

Thanks a lot for the link though. Are you into green electronics by any means ?

stefan_ wrote at 2021-12-04 17:41:06:

If you want to try this at home, keep in mind that powerline is essentially the same thing - you don't necessarily need some DSLAM. Also these things spew so much RF they can frequently pair through thin air, just from radiated emissions.

ksec wrote at 2021-12-04 15:21:05:

There used to be a debate about going All-in on GPON or doing FTTX with G.Fast. Now G.Fast is pretty much dead or niche at this point. The end of DSL era. While DOCSIS is still doing well in many places.

The next step would be to mandate fibre cables in all new housing. Along with ONT and Router in one solution.

Nextgrid wrote at 2021-12-04 16:39:04:

Better regulation around marketing would go a long ways to begin with. In the UK "fiber" is used as a catch-all term for any kind of internet connection even though in the majority of cases it's just fiber up to a certain point and then either DSL or coax, making it hard for consumers to tell exactly what they're signing up for. Same for bullshit terms such a "superfast" or "ultrafast" instead of actual up/down/latency numbers.

nabla9 wrote at 2021-12-04 15:40:32:

Most HDMI and Coaxial cables are little more than wet string

https://ec.europa.eu/docsroom/documents/46433

only 10% of the HDMI RMCD met an acceptable EMC quality of at least 50 dB coupling attenuation

Dylan16807 wrote at 2021-12-04 19:21:09:

RMCD sure is an awkward way of spelling "cable". Especially when nobody else seems to use this acronym?

mmastrac wrote at 2021-12-04 16:22:41:

The miracle of modern signal processing!

shireboy wrote at 2021-12-04 17:15:43:

I'm pretty sure this is exactly how my ATT DSL comes in.

account-5 wrote at 2021-12-04 16:11:06:

This is the article I'm sending to Sky next time my broadband goes down.

Nextgrid wrote at 2021-12-04 16:40:25:

Given the state of some telephone cabinets and junction boxes that I've seen, your broadband most likely already has some wet string in the path.

stkdump wrote at 2021-12-04 15:33:51:

I guess my home internet connection as a kid used wet string then.

Shikadi wrote at 2021-12-04 16:38:06:

That's impressive af!

rob_c wrote at 2021-12-04 18:16:38:

Have seen this one a few times, still impressive

traceroute66 wrote at 2021-12-04 14:00:25:

Why is this 2017 blog suddenly appearing here in 2021 ? Not surprisingly, it has already been covered many times:

- https://news.ycombinator.com/item?id=15908107
     - https://news.ycombinator.com/item?id=15922239
     - https://news.ycombinator.com/item?id=26868780

The world has also moved on since 2017. Most people's question now is "how soon can I get fibre" not "how can I tweak my ADSL line to scrape some extra performance".