Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Old TV caused village broadband outages for 18 months

bbc.com

Post reply on HN
Print view View original

261–270 of 304 posts

Re: Old TV caused village broadband outages for 18 months

#261

Post by lima »

bayindirh wrote: post #176
lima wrote: post #60

Earlier quoted context omitted.

> Ah, no. SNR problems in the shared medium is not something wathced or logged. A good ISP definitely does monitor SNR. It's a basic metric available from each individual customer device.

> It's a basic metric available from each individual customer device. Not mine. Good luck accessing to the modem you provided which I reconfigured to be a dumb bridge and terminated the ADSL connection on my router. Oh, the router neither see the POTS line (it only gets Ethernet) nor have remove management capabilities. Where endpoints are heterogeneous, there's guaranteed, real fun (Even more so if you make assumpti…

They still have SNR metrics on their end of the connection.

And this is why providers hate heterogeneous networks :-) Mine politely asks you to plug in the original modem before they'll help you debug a connectivity issue. But even then, there are sometimes standards like TR-069 that apply across vendors.

Re: Old TV caused village broadband outages for 18 months

#262

Post by lima »

formerly_proven wrote: post #126
heraclius wrote: post #73

Earlier quoted context omitted.

I should be rather surprised if the FCC were the relevant body in Wales.

Law concerning radio is very close to universal law.

Amazingly so! Even HAM radio regulations are remarkably harmonized internationally thanks to the IARU[1].

[1]: https://www.iaru.org

Re: Old TV caused village broadband outages for 18 months

#263

Post by ricardo81 »

sgt101 wrote: post #209
ricardo81 wrote: post #91

Earlier quoted context omitted.

Had an issue with line noise when I moved house. Took a while to figure out but apparently when it rained, I'd lose Internet connection. Took a bit of back and forth with British Telecom to convince them there's an issue after their continual "our tests indicate the line is OK"- if only they tested it when it was raining here! Line got replaced, apparently it was 60 years old. Worked a charm since.

The magic words are "the line is crackly when I try to hear someone" which will be recorded as "interference" and cause and engineer to be sent out. Then get them to open up any junction boxes that you can see. Normally the problem is that one of these has leaked causing poor coupling.

I wouldn't know about the finer details of physical telecommunications but in this case it would seem the physical (overhead) line that was about 30 metres from my property was allowing rainwater to interfere with the signal. That was what was replaced. Voice communication was never a problem (in the assumption I never spoke to people when it rained, I didn't often use the line for voice)

Re: Old TV caused village broadband outages for 18 months

#264

Post by _trampeltier »

saltspork wrote: post #116
ethanwillis wrote: post #93

I recently had my own host of cable internet issues. So about 3 months ago the RJ45 cable in my cable modem melted . I thought it was a freak accident. I checked all of my networking equipment, checked my outlets, etc. No problems. So I installed a new cable and then everything was fine. Cue 2 weeks ago. Connectivity became intermittent and then finally I had no internet for almost a week. Comcast wouldn't be able to…

Open neutrals are no joke, here’s a good analysis of a similar situation that caused a house fire: https://www.electrical-forensics.com/Open-Neutral/Open-Neutr... Here in Australia the coax connection from the street typically goes through a galvanic isolator to avoid this situation, rather than being bonded to the earth.

Open neutrals are no joke but each case does give a good story every time again. I know a guy who cut a 70mm2 neutral in a factory. They had a lot of single phase drive inverters. I think somethink like 25 inverters had to be replaced (and a lot of other stuff too).

Re: Old TV caused village broadband outages for 18 months

#265

Post by mturmon »

nucleardog wrote: post #240
throwanem wrote: post #157

Earlier quoted context omitted.

You can see water. It's a lot less potentially lethal, too. I understand how electricity works well enough to handle it safely - and, at least as important, to know when I can't handle it safely and it's time to call in a professional - but that's not the same as trusting it. Honestly, it's a lot more the same as not trusting it. I can and do prototype line-voltage filament LED lamp designs on my bench without a prob…

> All anyone has to do is screw up wiring an appliance with exposed metal parts, and the whole thing can be live at potentially lethal mains voltage Or for extra fun, the wiring in the house. Lots of people think things like changing a plug are "easy" (they are), but they're also really easy to screw up. Now you don't need some DIY'd appliance. Your Ikea stuff is now potentially deadly. The number of DIY jobs I've ru…

> But that nice shiny metal lamp you've got? It's got the neutral bonded to the body...

Another commenter pointed this out, but I have to chime in as well: no. Not true. The neutral is NOT bonded to the exterior body of a metal lamp. Not even on old fixtures built in the 1960s.

The old fixtures, if they were metal, were often not grounded, i.e. the lamp might not be connected by a 3-prong plug (hot, neutral, ground). But the neutral was definitely not bonded to the metal body.

If you inspect a new fixture, typically this means: it is either constructed with no accessible conductive parts, OR its metal case is bonded to the ground (not neutral!) and it has a 3-prong plug, OR it has a step-down transformer that converts to lower voltage before it enters the conductive lamp.

*

The thing that does happen when switching the neutral wire on a lamp is that doing so will energize the more-accessible "outer ring" of the Edison female receptacle rather than the less-accessible "center pin". This means that if you change the bulb with the switch on, you'd be more likely to contact the hot "outer ring".

Re: Old TV caused village broadband outages for 18 months

#266

Post by robocat »

saltspork wrote: post #116
ethanwillis wrote: post #93

I recently had my own host of cable internet issues. So about 3 months ago the RJ45 cable in my cable modem melted . I thought it was a freak accident. I checked all of my networking equipment, checked my outlets, etc. No problems. So I installed a new cable and then everything was fine. Cue 2 weeks ago. Connectivity became intermittent and then finally I had no internet for almost a week. Comcast wouldn't be able to…

Open neutrals are no joke, here’s a good analysis of a similar situation that caused a house fire: https://www.electrical-forensics.com/Open-Neutral/Open-Neutr... Here in Australia the coax connection from the street typically goes through a galvanic isolator to avoid this situation, rather than being bonded to the earth.

What do you mean by “galvanic isolator”? Link to coax example device? I’ve never heard the term before and a quick google is showing something irrelevant. NZer, so the language barrier exists!

Re: Old TV caused village broadband outages for 18 months

#267

Post by robocat »

Scoundreller wrote: post #184
gpuhacker wrote: post #48

I love these kind of stories. At Astron, the institute that builds and operates radio telescopes in the Netherlands, there's a story that they once gave a new TV to someone who lived a couple of villages from one of the telescopes, because the old set was causing too much radio interference. They could figure out the exact location of the old TV based on the data from the radio telescope

Then there’s a group of observant Jews that’ll sometimes drop by and kindly come by and fix your fence for free if it’s a part of their eruv, possibly before you know it’s broken https://nationalpost.com/news/canada/the-invisible-and-often...

> The Toronto eruv alone is estimated to cost $100,000 per year > But being difficult to maintain is kind of the point.

Why not implement it as an optical fibre?

Non-conducting and easy to continuously check that there are no breaks.

Re: Old TV caused village broadband outages for 18 months

#269

Post by JonathonW »

mturmon wrote: post #265
nucleardog wrote: post #240

Earlier quoted context omitted.

> All anyone has to do is screw up wiring an appliance with exposed metal parts, and the whole thing can be live at potentially lethal mains voltage Or for extra fun, the wiring in the house. Lots of people think things like changing a plug are "easy" (they are), but they're also really easy to screw up. Now you don't need some DIY'd appliance. Your Ikea stuff is now potentially deadly. The number of DIY jobs I've ru…

> But that nice shiny metal lamp you've got? It's got the neutral bonded to the body... Another commenter pointed this out, but I have to chime in as well: no. Not true. The neutral is NOT bonded to the exterior body of a metal lamp. Not even on old fixtures built in the 1960s. The old fixtures, if they were metal, were often not grounded, i.e. the lamp might not be connected by a 3-prong plug (hot, neutral, ground).…

> The thing that does happen when switching the neutral wire on a lamp is that doing so will energize the more-accessible "outer ring" of the Edison female receptacle rather than the less-accessible "center pin". This means that if you change the bulb with the switch on, you'd be more likely to contact the hot "outer ring".

Also, in most cases, the switch is only across (the wire that is supposed to be) the hot lead-- with neutral and hot swapped at the plug, you're not only energizing the outer ring of the light bulb socket, but also leaving it energized when the switch is off.

This leaves a shock hazard exposed even when the switch is off-- the lamp still won't light under normal circumstances because there's no path to ground with the switch off on the neutral line, but if you provide it one (your body) by touching it, you'll still get a shock regardless of the state of the switch.

Re: Old TV caused village broadband outages for 18 months

#270

Post by jhiesey »

robocat wrote: post #266
saltspork wrote: post #116

Earlier quoted context omitted.

Open neutrals are no joke, here’s a good analysis of a similar situation that caused a house fire: https://www.electrical-forensics.com/Open-Neutral/Open-Neutr... Here in Australia the coax connection from the street typically goes through a galvanic isolator to avoid this situation, rather than being bonded to the earth.

What do you mean by “galvanic isolator”? Link to coax example device? I’ve never heard the term before and a quick google is showing something irrelevant. NZer, so the language barrier exists!

Probably an isolation transformer. A search for “cable tv isolation transformer” gives lots of results.
Post reply on HN