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Groups > linux.debian.user > #211847 > unrolled thread
| Started by | Richard Owlett <rowlett@cloud85.net> |
|---|---|
| First post | 2019-07-29 12:50 +0200 |
| Last post | 2019-08-03 17:40 +0200 |
| Articles | 20 on this page of 97 — 25 participants |
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Wireless home LAN - WiFi vs Bluetooth? Richard Owlett <rowlett@cloud85.net> - 2019-07-29 12:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Reco <recoverym4n@enotuniq.net> - 2019-07-29 13:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Richard Owlett <rowlett@cloud85.net> - 2019-07-29 14:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Reco <recoverym4n@enotuniq.net> - 2019-07-29 14:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Dan Ritter <dsr@randomstring.org> - 2019-07-29 15:40 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? deloptes <deloptes@gmail.com> - 2019-07-30 11:30 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? John Hasler <jhasler@newsguy.com> - 2019-07-29 16:30 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Richard Owlett <rowlett@cloud85.net> - 2019-07-29 17:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? john doe <johndoe65534@mail.com> - 2019-07-29 14:10 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Reco <recoverym4n@enotuniq.net> - 2019-07-29 15:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Dan Ritter <dsr@randomstring.org> - 2019-07-29 15:40 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Joe <joe@jretrading.com> - 2019-07-29 15:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Dan Ritter <dsr@randomstring.org> - 2019-07-29 16:10 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-29 17:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Dan Ritter <dsr@randomstring.org> - 2019-07-29 18:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? John Hasler <jhasler@newsguy.com> - 2019-07-29 16:30 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Erik Christiansen <dvalin@internode.on.net> - 2019-07-29 16:40 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-29 16:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? rhkramer@gmail.com - 2019-07-30 05:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? John Hasler <jhasler@newsguy.com> - 2019-07-29 17:30 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Joe <joe@jretrading.com> - 2019-07-29 21:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-29 22:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Joe <joe@jretrading.com> - 2019-07-29 22:10 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-29 23:10 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? ghe <ghe@slsware.net> - 2019-07-29 23:30 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Gene Heskett <gheskett@shentel.net> - 2019-07-30 00:10 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-30 03:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Joe <joe@jretrading.com> - 2019-07-30 09:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Erik Christiansen <dvalin@internode.on.net> - 2019-07-30 13:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? John Hasler <jhasler@newsguy.com> - 2019-07-30 14:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Matthew Crews <mailinglists@mattcrews.com> - 2019-07-30 14:40 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Michael Stone <mstone@debian.org> - 2019-07-30 15:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-30 21:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Joe <joe@jretrading.com> - 2019-07-30 21:30 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-31 00:30 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Michael Stone <mstone@debian.org> - 2019-07-30 21:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-31 00:30 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? "Martin McCormick" <martin.m@suddenlink.net> - 2019-08-01 14:40 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? John Hasler <jhasler@newsguy.com> - 2019-07-30 15:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Gene Heskett <gheskett@shentel.net> - 2019-07-30 16:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-30 16:30 +0200
3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? rhkramer@gmail.com - 2019-07-30 17:40 +0200
Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? Erik Christiansen <dvalin@internode.on.net> - 2019-07-31 09:50 +0200
Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? Joe <joe@jretrading.com> - 2019-07-31 10:00 +0200
Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-08-01 15:50 +0200
Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? rhkramer@gmail.com - 2019-08-01 19:10 +0200
Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-08-01 21:50 +0200
Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? "James H. H. Lampert" <jamesl@touchtonecorp.com> - 2019-08-01 22:20 +0200
Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? Gene Heskett <gheskett@shentel.net> - 2019-08-01 23:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? mick crane <mick.crane@gmail.com> - 2019-08-03 18:30 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Joe <joe@jretrading.com> - 2019-08-03 20:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? mick crane <mick.crane@gmail.com> - 2019-08-03 21:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-29 23:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Patrick Bartek <nemommxiv@gmail.com> - 2019-07-29 17:30 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Celejar <celejar@gmail.com> - 2019-07-31 01:10 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Joe <joe@jretrading.com> - 2019-07-31 09:10 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Celejar <celejar@gmail.com> - 2019-08-02 16:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Reco <recoverym4n@enotuniq.net> - 2019-07-31 09:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Celejar <celejar@gmail.com> - 2019-07-31 14:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Reco <recoverym4n@enotuniq.net> - 2019-07-31 15:10 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Brian <ad44@cityscape.co.uk> - 2019-07-31 15:40 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Reco <recoverym4n@enotuniq.net> - 2019-07-31 15:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Ben Caradoc-Davies <ben@transient.nz> - 2019-08-01 03:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Celejar <celejar@gmail.com> - 2019-08-01 04:40 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Celejar <celejar@gmail.com> - 2019-08-01 04:40 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Reco <recoverym4n@enotuniq.net> - 2019-08-01 08:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Celejar <celejar@gmail.com> - 2019-08-01 04:40 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Reco <recoverym4n@enotuniq.net> - 2019-08-01 08:40 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Andrei POPESCU <andreimpopescu@gmail.com> - 2019-08-01 08:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Reco <recoverym4n@enotuniq.net> - 2019-08-01 10:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Celejar <celejar@gmail.com> - 2019-08-02 05:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Celejar <celejar@gmail.com> - 2019-08-02 05:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Andrei POPESCU <andreimpopescu@gmail.com> - 2019-07-31 22:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-29 17:00 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Patrick Bartek <nemommxiv@gmail.com> - 2019-07-29 17:20 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Richard Owlett <rowlett@cloud85.net> - 2019-07-29 18:00 +0200
PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} Richard Owlett <rowlett@cloud85.net> - 2019-07-29 19:00 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} David Wright <deblis@lionunicorn.co.uk> - 2019-07-29 23:10 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} Richard Owlett <rowlett@cloud85.net> - 2019-07-30 05:20 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} David Wright <deblis@lionunicorn.co.uk> - 2019-08-03 17:50 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} mick crane <mick.crane@gmail.com> - 2019-08-04 14:00 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} <tomas@tuxteam.de> - 2019-08-04 14:10 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} Richard Hector <richard@walnut.gen.nz> - 2019-08-04 17:20 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} rhkramer@gmail.com - 2019-08-05 18:50 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} David Wright <deblis@lionunicorn.co.uk> - 2019-08-05 22:00 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} Andrei POPESCU <andreimpopescu@gmail.com> - 2019-08-06 07:50 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} David Wright <deblis@lionunicorn.co.uk> - 2019-08-06 15:40 +0200
Re: PROGRESS!! - was {Re: Wireless home LAN - WiFi vs Bluetooth?} Andrei POPESCU <andreimpopescu@gmail.com> - 2019-08-07 08:50 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? Patrick Bartek <nemommxiv@gmail.com> - 2019-07-29 19:10 +0200
Re: Wireless home LAN - WiFi vs Bluetooth? David Wright <deblis@lionunicorn.co.uk> - 2019-07-29 18:40 +0200
Useful links - was {Re: Wireless home LAN - WiFi vs Bluetooth?} Richard Owlett <rowlett@cloud85.net> - 2019-08-03 15:20 +0200
Re: Useful links - was {Re: Wireless home LAN - WiFi vs Bluetooth?} Lee <ler762@gmail.com> - 2019-08-03 17:00 +0200
Re: Useful links - was {Re: Wireless home LAN - WiFi vs Bluetooth?} Richard Owlett <rowlett@cloud85.net> - 2019-08-03 17:30 +0200
Re: Useful links - was {Re: Wireless home LAN - WiFi vs Bluetooth?} David Wright <deblis@lionunicorn.co.uk> - 2019-08-03 17:50 +0200
Re: Useful links - was {Re: Wireless home LAN - WiFi vs Bluetooth?} Brian <ad44@cityscape.co.uk> - 2019-08-03 21:20 +0200
Re: Useful links - was {Re: Wireless home LAN - WiFi vs Bluetooth?} Andrei POPESCU <andreimpopescu@gmail.com> - 2019-08-03 18:20 +0200
Re: Useful links - was {Re: Wireless home LAN - WiFi vs Bluetooth?} David Wright <deblis@lionunicorn.co.uk> - 2019-08-03 17:40 +0200
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| From | David Wright <deblis@lionunicorn.co.uk> |
|---|---|
| Date | 2019-07-30 16:30 +0200 |
| Message-ID | <ypBiy-57X-1@gated-at.bofh.it> |
| In reply to | #211913 |
On Tue 30 Jul 2019 at 14:30:50 (+0200), Matthew Crews wrote: > On 7/29/19 12:57 PM, David Wright wrote: > > On Mon 29 Jul 2019 at 20:43:04 (+0100), Joe wrote: > >> On Mon, 29 Jul 2019 10:26:14 -0500 John Hasler <jhasler@newsguy.com> wrote: > >> > >>> They don't have to be on the same branch circuit: just on the same > >>> "phase"[1]. There is probably a gadget available that bridges the > >>> signal between phases. > >>> > >>> [1] They aren't really phases but everyone calls them that. > >> > >> They are in my country. 3-phase, 240V RMS each phase to neutral, 415V > >> RMS between phases. > > > > Irrelevant in a domestic setting: it's illegal to have more than one > > phase in an ordinary house. Houses will have one phase each, so you'll > > share your phase with various neighbours scattered along the street. > > How do you figure? As I pointed out elsewhere, "my country" is the UK where domestiv voltages are twice those in the US. There are people who run small workshops where they have managed to install 3 phase supplies. If you read up their accounts, most of them are operating very much at the edge of legality with respect to building regs, planning laws (US zoning) and running businesses in domestic premises. I never got the impression that enforcement in this area was thorough. In large residential blocks, you get 3 phase supplied to the block, but they're typically split so that individual floors in a block of flats will all be on one phase. But you're bound to get exceptions: for example, our house was temporarily (over a year) connected to supplies from two different streets so running a vacuum cleaner across the bridge could be mixing phases. However, that was at US voltages, not UK ones. > In the US most 240V outlets are 3 phase, and they are > relatively common. You need them for most ovens, washing machines, and > electric cars. I'm not sure where you get that impression, but I suspect it's from counting pins on the appliance plugs. But look at the plate on the back of the appliance or the installation leaflet and you'll see they're 240v and they just take both 110v hot lines from both sides of the breaker box. That's two pins; the third is neutral and the fourth is earth. Obsolete 3-pin appliances have earth and neutral combined on a single pin. For cars, that makes them charge at level 2 (level 1 is through a normal 110v outlet, so slow). As for washing machines, in my experience, most here are hot and cold fill, whereas the UK has gazillions of cold fill. I would hate to pay for heating up a top-loading cold fill washing machine with electricity. That's not to say there are no 3-phase supplies in the US, but I've never come across them. As they're still 110v, you wouldn't see any difference as a visitor, of course. But you have a problem with 240v items like those above, because the voltage between any two hot lines is only just over 200v. As I say, I've not knowingly encountered it; perhaps the woman in Austin TX has. People who've spent all their lives here might know more. Cheers, David.
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| From | rhkramer@gmail.com |
|---|---|
| Date | 2019-07-30 17:40 +0200 |
| Subject | 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? |
| Message-ID | <ypCoi-5Lb-9@gated-at.bofh.it> |
| In reply to | #211919 |
I was trained as an electrical engineer, and I'd love to be able to clarify the situation, I'm not sure I can without using far too many words. 3 phase power (around the world as far as I know) consists of (usually) 3 wires carrying electrical power at a given frequency (in the US, 60 Hz., in some other countries 50 Hz., and, once upon a time (and maybe still in some places (including at one time parts of the US (or industries therein) at 25 hz. A fourth wire may be a neutral wire (grounded or not), and there may be a 5th wire as a safety ground). The key thing is that those hot wires are carrying power that is 120 degrees out of phase with the other two wires. (One of the key advantages of this arrangement is that it makes it easy to create a rotating magnetic field which is the key thing that makes lots of motors work (there are DC motors and single phase motors that work on somewhat different approaches). Most residential power in the US is created using a single phase transformer (so called because (1) it only takes power from one of the 3 phases mentioned above and (2) darn -- it's a bitch getting old. The secondary of that transformer is center tapped with the center tap almost always grounded, such that the other two taps from the secondary both produce 120 volts (RMS nominal), but out of phase with each other by 180 degrees. From the standpoint of the English language (at least the common American dialects), I see nothing inherently wrong with calling those two hot wires (the non-grounded end taps) as phases, because, they are, indeed, 180 degrees out of phase, but that is not the common terminology. More commonly it is just called (or what I call it) 240/120 volt single phase power. If you need 120 volts, you connect from one hot tap to the center tap. If you need 240 volts, you connect to the two end / hot taps. I have seen diagrams in NEC code books for a different arrangement to get 120 volt 3 phase power, but I don't recall ever actually encountering that in real life. In that case, iirc, 120 volt loads are connected from a hot tap to the neutral wire (the 4th wire of the 3 phase arrangement), and you get (nominally) 208 volts (RMS) connecting phase to phase. I have seen things like motors that were rated like 240 / 208 volts (or something like that). I hope this is at least somewhat helpful. On Tuesday, July 30, 2019 10:26:23 AM David Wright wrote: > On Tue 30 Jul 2019 at 14:30:50 (+0200), Matthew Crews wrote: > > On 7/29/19 12:57 PM, David Wright wrote: > > > On Mon 29 Jul 2019 at 20:43:04 (+0100), Joe wrote: > > >> On Mon, 29 Jul 2019 10:26:14 -0500 John Hasler <jhasler@newsguy.com> wrote: > > >>> They don't have to be on the same branch circuit: just on the same > > >>> "phase"[1]. There is probably a gadget available that bridges the > > >>> signal between phases. > > >>> > > >>> [1] They aren't really phases but everyone calls them that. > > >> > > >> They are in my country. 3-phase, 240V RMS each phase to neutral, 415V > > >> RMS between phases. > > > > > > Irrelevant in a domestic setting: it's illegal to have more than one > > > phase in an ordinary house. Houses will have one phase each, so you'll > > > share your phase with various neighbours scattered along the street. > > > > How do you figure? > > As I pointed out elsewhere, "my country" is the UK where domestiv > voltages are twice those in the US. There are people who run small > workshops where they have managed to install 3 phase supplies. If > you read up their accounts, most of them are operating very much at > the edge of legality with respect to building regs, planning laws > (US zoning) and running businesses in domestic premises. I never > got the impression that enforcement in this area was thorough. > > In large residential blocks, you get 3 phase supplied to the block, > but they're typically split so that individual floors in a block > of flats will all be on one phase. But you're bound to get exceptions: > for example, our house was temporarily (over a year) connected to > supplies from two different streets so running a vacuum cleaner across > the bridge could be mixing phases. However, that was at US voltages, > not UK ones. > > > In the US most 240V outlets are 3 phase, and they are > > relatively common. You need them for most ovens, washing machines, and > > electric cars. > > I'm not sure where you get that impression, but I suspect it's from > counting pins on the appliance plugs. But look at the plate on the > back of the appliance or the installation leaflet and you'll see > they're 240v and they just take both 110v hot lines from both sides > of the breaker box. That's two pins; the third is neutral and the > fourth is earth. Obsolete 3-pin appliances have earth and neutral > combined on a single pin. > > For cars, that makes them charge at level 2 (level 1 is through a > normal 110v outlet, so slow). As for washing machines, in my > experience, most here are hot and cold fill, whereas the UK has > gazillions of cold fill. I would hate to pay for heating up a > top-loading cold fill washing machine with electricity. > > That's not to say there are no 3-phase supplies in the US, but > I've never come across them. As they're still 110v, you wouldn't > see any difference as a visitor, of course. But you have a problem > with 240v items like those above, because the voltage between any > two hot lines is only just over 200v. As I say, I've not knowingly > encountered it; perhaps the woman in Austin TX has. People who've > spent all their lives here might know more. > > Cheers, > David.
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| From | Erik Christiansen <dvalin@internode.on.net> |
|---|---|
| Date | 2019-07-31 09:50 +0200 |
| Subject | Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? |
| Message-ID | <ypRwZ-6KZ-9@gated-at.bofh.it> |
| In reply to | #211920 |
On 30.07.19 11:34, rhkramer@gmail.com wrote: > Most residential power in the US is created using a single phase transformer > (so called because (1) it only takes power from one of the 3 phases mentioned > above and (2) darn -- it's a bitch getting old. Tell me about it. ;-) I'd offer that (2) is simply that there's only one primary and one secondary, not three of each, on multiple arms of the core. > The secondary of that > transformer is center tapped with the center tap almost always grounded, such > that the other two taps from the secondary both produce 120 volts (RMS > nominal), but out of phase with each other by 180 degrees. Those details on this thread have been interesting, because 120v is unknown down under - and, I think, in the UK. Erik
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| From | Joe <joe@jretrading.com> |
|---|---|
| Date | 2019-07-31 10:00 +0200 |
| Subject | Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? |
| Message-ID | <ypRGG-6Pl-19@gated-at.bofh.it> |
| In reply to | #211954 |
On Wed, 31 Jul 2019 17:47:13 +1000 Erik Christiansen <dvalin@internode.on.net> wrote: > On 30.07.19 11:34, rhkramer@gmail.com wrote: > > Most residential power in the US is created using a single phase > > transformer (so called because (1) it only takes power from one of > > the 3 phases mentioned above and (2) darn -- it's a bitch getting > > old. > > Tell me about it. ;-) I'd offer that (2) is simply that there's only > one primary and one secondary, not three of each, on multiple arms of > the core. > > > The secondary of that > > transformer is center tapped with the center tap almost always > > grounded, such that the other two taps from the secondary both > > produce 120 volts (RMS nominal), but out of phase with each other > > by 180 degrees. > > Those details on this thread have been interesting, because 120v is > unknown down under - and, I think, in the UK. > We use it for tools on construction sites, hopefully through isolating transformers. I had some trouble getting permission to use a 240V soldering iron inside a train factory in the UK. -- Joe
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| From | David Wright <deblis@lionunicorn.co.uk> |
|---|---|
| Date | 2019-08-01 15:50 +0200 |
| Subject | Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? |
| Message-ID | <yqjCV-7OE-5@gated-at.bofh.it> |
| In reply to | #211920 |
On Tue 30 Jul 2019 at 11:34:43 (-0400), rhkramer@gmail.com wrote: > […] > The key thing is that those hot wires are carrying power that is 120 degrees > out of phase with the other two wires. (One of the key advantages of this > arrangement is that it makes it easy to create a rotating magnetic field which > is the key thing that makes lots of motors work (there are DC motors and > single phase motors that work on somewhat different approaches). > > Most residential power in the US is created using a single phase transformer > (so called because (1) it only takes power from one of the 3 phases mentioned > above and (2) darn -- it's a bitch getting old. The secondary of that > transformer is center tapped with the center tap almost always grounded, such > that the other two taps from the secondary both produce 120 volts (RMS > nominal), but out of phase with each other by 180 degrees. > > From the standpoint of the English language (at least the common American > dialects), I see nothing inherently wrong with calling those two hot wires > (the non-grounded end taps) as phases, because, they are, indeed, 180 degrees > out of phase, but that is not the common terminology. Your first paragraph answers the implied question: the lack of any rotation. Rather similar to a steam locomotive with the motion on the two sides incorrectly set 180° apart. If the locomotive came to rest in front dead centre on one side (piston at forward extremity), it would also be dead centre (backward extremity) on the other side, and consequently unable to move in either direction. Like a real locomotive, genuine '2-phase' electrical power has one phase leading the other by 90°, and motors powered by it will be self-starting. (Steam locomotives have double-acting pistons, so they can choose the direction of rotation.) Hence it's not useful for electrical engineers to call a split single-phase supply by the term '2-phase' because it doesn't behave in a similar way to all other n-phase supplies, like interconversion. Cheers, David.
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| From | rhkramer@gmail.com |
|---|---|
| Date | 2019-08-01 19:10 +0200 |
| Subject | Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? |
| Message-ID | <yqmKt-1xh-3@gated-at.bofh.it> |
| In reply to | #212053 |
On Thursday, August 01, 2019 09:41:45 AM David Wright wrote: > Like a real locomotive, genuine '2-phase' electrical power has one > phase leading the other by 90°, and motors powered by it will be > self-starting. (Steam locomotives have double-acting pistons, so they > can choose the direction of rotation.) Have you ever encountered genuiine 2 phase electrical power? (Or any multiphase power other than 3 phase?) (Just curious -- I could not instantly think of an example.)
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| From | David Wright <deblis@lionunicorn.co.uk> |
|---|---|
| Date | 2019-08-01 21:50 +0200 |
| Subject | Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? |
| Message-ID | <yqpfj-2Wl-5@gated-at.bofh.it> |
| In reply to | #212086 |
On Thu 01 Aug 2019 at 13:06:41 (-0400), rhkramer@gmail.com wrote: > On Thursday, August 01, 2019 09:41:45 AM David Wright wrote: > > Like a real locomotive, genuine '2-phase' electrical power has one > > phase leading the other by 90°, and motors powered by it will be > > self-starting. (Steam locomotives have double-acting pistons, so they > > can choose the direction of rotation.) > > Have you ever encountered genuiine 2 phase electrical power? (Or any > multiphase power other than 3 phase?) (Just curious -- I could not instantly > think of an example.) No—long before my time. OTOH Direct Current was still being used in a few areas of the UK when I was at college in the late 1960s, about the same time as the UK converted from town gas (H&CO) to natural gas. (Quite an upheaval for those undergoing both.) I went to a field centre in Gloucestershire in late 1971 where some of the equipment was still running on DC, and plugged in with these things: https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#UK_Walsall_Gauge_plug By this time, I believe that all domestic customers had changed over. There used to be plenty of 2-phase about, the best known example being what was the largest installation in its day: Niagara Falls. Nowadays, I see Philadelphia is one of the last places remaining. https://www.peco.com/SiteCollectionDocuments/CurrentElecTariff.pdf shows that their domestic voltages are supplied with both polarities (5-wire) whereas 2400v is just 3-wire. Cheers, David.
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| From | "James H. H. Lampert" <jamesl@touchtonecorp.com> |
|---|---|
| Date | 2019-08-01 22:20 +0200 |
| Subject | Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? |
| Message-ID | <yqpIl-3lQ-7@gated-at.bofh.it> |
| In reply to | #212108 |
Hmm. And as anybody old enough to have grown up on "Emergency!" (and to remember a rescue involving a worker caught in a vinyl record press), if you reverse any two of the three hot wires on a 3-phase motor, you reverse the direction of rotation. Which caused a rather amusing malfunction at the International Printing Museum, where I spend my Saturdays docenting: our Heidelberg cylinder press was not feeding paper, and we eventually realized it was running backwards, because somebody working on the wiring had gotten two wires switched. Thank God it wasn't the Heidelberg Windmill: you run those backwards more than 1 or 2 degrees, and they shred themselves. -- James H. H. Lampert
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| From | Gene Heskett <gheskett@shentel.net> |
|---|---|
| Date | 2019-08-01 23:20 +0200 |
| Subject | Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth? |
| Message-ID | <yqqEq-3X9-7@gated-at.bofh.it> |
| In reply to | #212086 |
On Thursday 01 August 2019 13:06:41 rhkramer@gmail.com wrote: > On Thursday, August 01, 2019 09:41:45 AM David Wright wrote: > > Like a real locomotive, genuine '2-phase' electrical power has one > > phase leading the other by 90°, and motors powered by it will be > > self-starting. (Steam locomotives have double-acting pistons, so > > they can choose the direction of rotation.) > > Have you ever encountered genuiine 2 phase electrical power? (Or any > multiphase power other than 3 phase?) (Just curious -- I could not > instantly think of an example.) I think it has fallen out of use, the last I saw a 2 phase motor was in a garage my in-law uncle built when he got back from WWII and REA came down the road, running a cutoff wheel that was probably older than the uncle. REA was back the next year, stringing the 3rd wire for 3 phase on that mainline. So those poles still stand, carrying the neutral on th tops of the poles and 2 14.4 kv lines on one side of the crossbar, and a third one on the other end of the crossbar. And I've noticed the wires are rotated about 2x a mile. Load balancing perhaps, so when they hang another can, the mechanical hookup is the same but its on a different phase from the neighbor half a mile down the road. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene>
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| From | mick crane <mick.crane@gmail.com> |
|---|---|
| Date | 2019-08-03 18:30 +0200 |
| Message-ID | <yr54S-4i1-7@gated-at.bofh.it> |
| In reply to | #211913 |
On 2019-07-30 13:30, Matthew Crews wrote: > On 7/29/19 12:57 PM, David Wright wrote: >> On Mon 29 Jul 2019 at 20:43:04 (+0100), Joe wrote: >>> On Mon, 29 Jul 2019 10:26:14 -0500 John Hasler <jhasler@newsguy.com> >>> wrote: >>> >>>> They don't have to be on the same branch circuit: just on the same >>>> "phase"[1]. There is probably a gadget available that bridges the >>>> signal between phases. >>>> >>>> [1] They aren't really phases but everyone calls them that. >>> >>> They are in my country. 3-phase, 240V RMS each phase to neutral, 415V >>> RMS between phases. >> >> Irrelevant in a domestic setting: it's illegal to have more than one >> phase in an ordinary house. Houses will have one phase each, so you'll >> share your phase with various neighbours scattered along the street. > > How do you figure? In the US most 240V outlets are 3 phase, and they > are > relatively common. You need them for most ovens, washing machines, and > electric cars. I don't really understand how 3 phase motors work. Is normally wanted if you have some heavy equipment like a car crusher. As I understand each cable has 130 or something volts where the AC is 120 degrees out of sinc so putting a resistance between one of the cables and earth would give you just that ~130 volts. Somehow a 3 phase motor must get the feeds back in sinc so you get the 415 Volts. mick -- Key ID 4BFEBB31
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| From | Joe <joe@jretrading.com> |
|---|---|
| Date | 2019-08-03 20:20 +0200 |
| Message-ID | <yr6Nj-5pi-1@gated-at.bofh.it> |
| In reply to | #212206 |
On Sat, 03 Aug 2019 17:28:24 +0100 mick crane <mick.crane@gmail.com> wrote: > On 2019-07-30 13:30, Matthew Crews wrote: > > On 7/29/19 12:57 PM, David Wright wrote: > >> On Mon 29 Jul 2019 at 20:43:04 (+0100), Joe wrote: > >>> On Mon, 29 Jul 2019 10:26:14 -0500 John Hasler > >>> <jhasler@newsguy.com> wrote: > >>> > >>>> They don't have to be on the same branch circuit: just on the > >>>> same "phase"[1]. There is probably a gadget available that > >>>> bridges the signal between phases. > >>>> > >>>> [1] They aren't really phases but everyone calls them that. > >>> > >>> They are in my country. 3-phase, 240V RMS each phase to neutral, > >>> 415V RMS between phases. > >> > >> Irrelevant in a domestic setting: it's illegal to have more than > >> one phase in an ordinary house. Houses will have one phase each, > >> so you'll share your phase with various neighbours scattered along > >> the street. > > > > How do you figure? In the US most 240V outlets are 3 phase, and > > they are > > relatively common. You need them for most ovens, washing machines, > > and electric cars. > > I don't really understand how 3 phase motors work. Is normally wanted > if you have some heavy equipment like a car crusher. > As I understand each cable has 130 or something volts where the AC is > 120 degrees out of sinc so putting a resistance between one of the > cables and earth would give you just that ~130 volts. > Somehow a 3 phase motor must get the feeds back in sinc so you get > the 415 Volts. A three-phase motor is pretty much three single phase motors with a shared armature. The point about it is that the three magnetic propulsive forces arrive in a definite order, so the motor is always guaranteed to start and turn in the same direction every time. Single-phase motors must use dodges like extra windings linked to capacitors and even a partly short-circuited area of the ironwork (shaded pole) in order to start up and run in a particular direction. The three-phase motor doesn't need anything like this, so is conceptually simpler. Three phases allows lower currents in the cables than a single-phase motor of the same power, and can run on three wires only, without the need for a neutral wire. There's no need for any 'syncing'. In a three-phase power system, the voltage between two phases is always the single phase to neutral voltage multiplied by the square root of three. https://www.raritan.com/landing/three-phase-power-explained -- Joe
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| From | mick crane <mick.crane@gmail.com> |
|---|---|
| Date | 2019-08-03 21:00 +0200 |
| Message-ID | <yr7q1-5Dh-1@gated-at.bofh.it> |
| In reply to | #212211 |
On 2019-08-03 19:10, Joe wrote: <snipped> > Three phases allows lower currents in the cables than a single-phase > motor of the same power, and can run on three wires only, without the > need for a neutral wire. There's no need for any 'syncing'. In a > three-phase power system, the voltage between two phases is always the > single phase to neutral voltage multiplied by the square root of three. > > https://www.raritan.com/landing/three-phase-power-explained cheers mick -- Key ID 4BFEBB31
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| From | David Wright <deblis@lionunicorn.co.uk> |
|---|---|
| Date | 2019-07-29 23:00 +0200 |
| Message-ID | <ypkUp-3eE-11@gated-at.bofh.it> |
| In reply to | #211871 |
On Mon 29 Jul 2019 at 10:26:14 (-0500), John Hasler wrote: > They don't have to be on the same branch circuit: just on the same > "phase"[1]. There is probably a gadget available that bridges the > signal between phases. > > [1] They aren't really phases but everyone calls them that. Yes, the pole transformer is fed with one of the universal three phases. Easy to see on our street as only one phase is strung along the tops of the poles. The transformer output is a centre-tapped 220v supply, so you get supplied with two live feeds 180° out of phase with each other and the earthed centre-tap. The live feeds come into the breaker box and run down two busbars, on the left and the right. The switches are in two vertical rows along the busbars. At the top are the double-pole switches that connect dryers, AC compressors, etc to both busbars because they need 220v. The single switches below them are only connected to the busbar on their side, so anything switched on the left side is on the other busbar from those on the right. Our house is in two parts. The old part had power from a different street, strung across the back garden. The new part has power from the street. The old part's breaker box is now fed from the top switch (a double) in the new house's box. So both boxes have access to the left and right circuits. I just took our "roving" fourth Powerline devices and a laptop (wifi off) round both houses to rooms on each of the busbars. Every socket outlet works, including GFCI ones. (As I mentioned earlier, I always get the devices to exchange keys in the kitchen, where all the outlets are GFCI protected.) So I can find no evidence that the circuit matters. I can only suppose that there are other factors causing problems reported by others. For example, in our previous house there were sockets that had live on the wrong pin. Other people might already have marginal performance caused by mixing manufacturers. Every case is different. Cheers, David.
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| From | Patrick Bartek <nemommxiv@gmail.com> |
|---|---|
| Date | 2019-07-29 17:30 +0200 |
| Message-ID | <ypfL3-8rM-5@gated-at.bofh.it> |
| In reply to | #211853 |
On Mon, 29 Jul 2019 14:05:02 +0200 john doe <johndoe65534@mail.com> wrote: > On 7/29/2019 12:57 PM, Reco wrote: > > Hi. > > > > On Mon, Jul 29, 2019 at 05:40:40AM -0500, Richard Owlett wrote: > >> A concern is security issues. Bluetooth, being short range, may thus > >> have an advantage. Speed is not an issue for my expected usage. (I was > >> one of my ISP's last 6 dial-up clients ;) > > > > Both have their disadvantages in this regard. > > > > WPA2's (that's your conventional WiFi standard) secure configuration is > > fiendishly difficult. > > You have beacon frames that are broadcasted without any encryption. > > You have authentication frames that can be intercepted (so WPA > > passphrase can be bruteforced). > > You have several encryption algorithms, but: > > a) They are not equally good. > > b) You may have a hardware that lack support for a good ones. > > > > They do have WPA3 that promises to fix all this, but ... you and I do > > not have the hardware for it yet. > > > > > > Bluetooth, on the other hand, is a security nightmare. > > First, they got reasonable encryption in 4.0 standard version, and it's > > optional. You have certain "profiles" that willingly elect to forbid > > encryption. > > Second, authentication aka "pairing" (which is optional too). In its > > most common form authentication key is a four-digit number, with most > > devices preset to four zeroes. > > > > > > In short, nothing beats Ethernet in your typical household for > > conventional computing needs. Smartphones and tablets may convince you > > to use WiFi, but these devices are insecure anyway, so there's no loss. > > > > What about Powerline (PLC), any better then Wireless with regard to > security? I checked into this option myself. One caveat: For it to work the router and computers have to be on the same household electrical circuit. That is, if the router is on the "office" circuit and the computer(s) are on the "bedroom" circuit, it won't work. Just look at your breakerbox: each breaker is a separate circuit. Also if you have any electric devices running on the circuit being used to network, you'll get interferance. Plus, you have to buy an adapter for the router and each computer. I considered this a last resort option. B
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| From | Celejar <celejar@gmail.com> |
|---|---|
| Date | 2019-07-31 01:10 +0200 |
| Message-ID | <ypJpL-1Km-3@gated-at.bofh.it> |
| In reply to | #211848 |
On Mon, 29 Jul 2019 13:57:25 +0300 Reco <recoverym4n@enotuniq.net> wrote: ... > WPA2's (that's your conventional WiFi standard) secure configuration is > fiendishly difficult. I take your point, but "fiendishly difficult"? I think you're exaggerating. > You have beacon frames that are broadcasted without any encryption. True, but is there any evidence that this constitutes a security risk? > You have authentication frames that can be intercepted (so WPA > passphrase can be bruteforced). Lots of things (such as TLS, ssh) can theoretically be brute forced - the question is whether such brute forcing is sufficiently practical to be a threat. I have seen nothing to indicate that properly configured WPA2 can be realistically brute forced. > You have several encryption algorithms, but: > a) They are not equally good. Of course not - they never are ;) The trick is to pick a good one, and for wifi, that's WPA2 using AES. > b) You may have a hardware that lack support for a good ones. I suppose, but my impression is that most hardware from the last few years is fine. Celejar
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| From | Joe <joe@jretrading.com> |
|---|---|
| Date | 2019-07-31 09:10 +0200 |
| Message-ID | <ypQUi-6vy-3@gated-at.bofh.it> |
| In reply to | #211943 |
On Tue, 30 Jul 2019 19:06:08 -0400 Celejar <celejar@gmail.com> wrote: > On Mon, 29 Jul 2019 13:57:25 +0300 > Reco <recoverym4n@enotuniq.net> wrote: > > ... > > > WPA2's (that's your conventional WiFi standard) secure > > configuration is fiendishly difficult. > > I take your point, but "fiendishly difficult"? I think you're > exaggerating. > I take it we're talking RADIUS here? There are several different things to get exactly right, otherwise it just sulks and doesn't tell you why. It took me about three days last time I tried it, several years ago. I'm in the process of trying it again, I believe (!) that I have FreeRADIUS and the certificates right, now I'm trying to get both the enthusiasm and the time to finish it. I had a try at installing certificates on a stretch netbook using Network Manager, but the 'save' button stayed greyed out, and no, it wouldn't tell me why. I'll probably try it on a Windows laptop, with more confidence of it working. And I know that my Cisco router has a bug around the RADIUS configuration. I can't recall what it is, but I found a workaround before so I'll probably manage it again. It manifests itself by (silently) not sending anything to the server. Great. But plug and play? No way. 'Fiendishly difficult'? Mmmmm, I'll tell you that after I've got it working. -- Joe
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| From | Celejar <celejar@gmail.com> |
|---|---|
| Date | 2019-08-02 16:20 +0200 |
| Message-ID | <yqGzv-5Gm-3@gated-at.bofh.it> |
| In reply to | #211953 |
On Wed, 31 Jul 2019 08:01:40 +0100 Joe <joe@jretrading.com> wrote: > On Tue, 30 Jul 2019 19:06:08 -0400 > Celejar <celejar@gmail.com> wrote: > > > On Mon, 29 Jul 2019 13:57:25 +0300 > > Reco <recoverym4n@enotuniq.net> wrote: > > > > ... > > > > > WPA2's (that's your conventional WiFi standard) secure > > > configuration is fiendishly difficult. > > > > I take your point, but "fiendishly difficult"? I think you're > > exaggerating. > > > > I take it we're talking RADIUS here? There are several different things No, I meant simple Personal / PSK. Celejar
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| From | Reco <recoverym4n@enotuniq.net> |
|---|---|
| Date | 2019-07-31 09:50 +0200 |
| Message-ID | <ypRwZ-6KZ-13@gated-at.bofh.it> |
| In reply to | #211943 |
Hi. On Tue, Jul 30, 2019 at 07:06:08PM -0400, Celejar wrote: > On Mon, 29 Jul 2019 13:57:25 +0300 > Reco <recoverym4n@enotuniq.net> wrote: > > ... > > > WPA2's (that's your conventional WiFi standard) secure configuration is > > fiendishly difficult. > > I take your point, but "fiendishly difficult"? I think you're > exaggerating. WPA Enterprise. 802.1r. An "interesting" choice between CCMP and TKIP (yep, it's hardware dependent). De-authentication attacks. "Evil twin" attacks. I meant it when I wrote "fiendishly difficult". > > You have beacon frames that are broadcasted without any encryption. > > True, but is there any evidence that this constitutes a security risk? Some people believe that hiding AP name gives them another layer of security. Beacon frames prove otherwise. > > You have authentication frames that can be intercepted (so WPA > > passphrase can be bruteforced). > > Lots of things (such as TLS, ssh) can theoretically be brute forced - > the question is whether such brute forcing is sufficiently practical to > be a threat. I have seen nothing to indicate that properly configured > WPA2 can be realistically brute forced. For WPA2 it's not that hard really, assuming pre-shared key usage. Can be expensive (all those videocards and ASICs have their cost), but definitely doable. > > You have several encryption algorithms, but: > > a) They are not equally good. > > Of course not - they never are ;) The trick is to pick a good one, and > for wifi, that's WPA2 using AES. See above. > > b) You may have a hardware that lack support for a good ones. > > I suppose, but my impression is that most hardware from the last few > years is fine. Cheap smartphones and tablets. Whatever they put instead of a proper WiFi in printers (yep, I'm looking at you, HP). Oh, D-Link and Linksys. There are *always* some exceptions to "newer is the better" rule. Reco
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| From | Celejar <celejar@gmail.com> |
|---|---|
| Date | 2019-07-31 14:00 +0200 |
| Message-ID | <ypVqV-Oo-7@gated-at.bofh.it> |
| In reply to | #211955 |
On Wed, 31 Jul 2019 10:43:48 +0300 Reco <recoverym4n@enotuniq.net> wrote: > Hi. > > On Tue, Jul 30, 2019 at 07:06:08PM -0400, Celejar wrote: > > On Mon, 29 Jul 2019 13:57:25 +0300 > > Reco <recoverym4n@enotuniq.net> wrote: > > > > ... > > > > > WPA2's (that's your conventional WiFi standard) secure configuration is > > > fiendishly difficult. > > > > I take your point, but "fiendishly difficult"? I think you're > > exaggerating. > > WPA Enterprise. 802.1r. An "interesting" choice between CCMP and TKIP > (yep, it's hardware dependent). De-authentication attacks. "Evil twin" > attacks. > > I meant it when I wrote "fiendishly difficult". I'm afraid that I'm missing your point. The context here was a home user choosing between wifi and wired ethernet, and you are arguing that configuring wifi securely is fiendishly difficult. Why are we talking about WPA Enterprise, as opposed to PSK? > > > You have beacon frames that are broadcasted without any encryption. > > > > True, but is there any evidence that this constitutes a security risk? > > Some people believe that hiding AP name gives them another layer of > security. Beacon frames prove otherwise. Certainly, but that has no bearing on the underlying question of whether wifi can be configured to be tolerably secure in a reasonably straightforward fashion by a home user. > > > You have authentication frames that can be intercepted (so WPA > > > passphrase can be bruteforced). > > > > Lots of things (such as TLS, ssh) can theoretically be brute forced - > > the question is whether such brute forcing is sufficiently practical to > > be a threat. I have seen nothing to indicate that properly configured > > WPA2 can be realistically brute forced. > > For WPA2 it's not that hard really, assuming pre-shared key usage. > Can be expensive (all those videocards and ASICs have their cost), but > definitely doable. I'd be interested in seeing some real-world studies, or simply just a mathematical analysis of how much hardware would be necessary to crack a good WPA2 password. I've seen lots of sites explaining how to use hashcat with a GPU, and various real-world tests on lists of hashed passwords (e.g., [1]), but can you provide a serious analysis of the practical cost, in time or hardware, of cracking a real-world WPA setup? > You have several encryption algorithms, but: ... > > > b) You may have a hardware that lack support for a good ones. > > > > I suppose, but my impression is that most hardware from the last few > > years is fine. > > Cheap smartphones and tablets. Whatever they put instead of a proper This misses the point - we're comparing ethernet to wifi. Cheap smartphones and tablets aren't usually going to support ethernet. > WiFi in printers (yep, I'm looking at you, HP). Oh, D-Link and Linksys. > There are *always* some exceptions to "newer is the better" rule. D-Link and Linksys don't support WPA2-PSK with AES? [1] https://arstechnica.com/information-technology/2013/05/how-crackers-make-minced-meat-out-of-your-passwords/ Celejar
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| From | Reco <recoverym4n@enotuniq.net> |
|---|---|
| Date | 2019-07-31 15:10 +0200 |
| Message-ID | <ypWwG-1Hs-13@gated-at.bofh.it> |
| In reply to | #211967 |
Hi. On Wed, Jul 31, 2019 at 07:58:54AM -0400, Celejar wrote: > On Wed, 31 Jul 2019 10:43:48 +0300 > Reco <recoverym4n@enotuniq.net> wrote: > > > Hi. > > > > On Tue, Jul 30, 2019 at 07:06:08PM -0400, Celejar wrote: > > > On Mon, 29 Jul 2019 13:57:25 +0300 > > > Reco <recoverym4n@enotuniq.net> wrote: > > > > > > ... > > > > > > > WPA2's (that's your conventional WiFi standard) secure configuration is > > > > fiendishly difficult. > > > > > > I take your point, but "fiendishly difficult"? I think you're > > > exaggerating. > > > > WPA Enterprise. 802.1r. An "interesting" choice between CCMP and TKIP > > (yep, it's hardware dependent). De-authentication attacks. "Evil twin" > > attacks. > > > > I meant it when I wrote "fiendishly difficult". > > I'm afraid that I'm missing your point. The context here was a home > user choosing between wifi and wired ethernet, and you are arguing that > configuring wifi securely is fiendishly difficult. Why are we talking > about WPA Enterprise, as opposed to PSK? If you need to eavesdrop Ethernet you need to tap wires physically. If you need to eavesdrop WiFi then all you need is 802.1x compliant card and to be in range. Hence WPA encryption is a vital part of WiFi security. Such encryption is as good as the session key, transmission of which is protected either by PSK (bad), EAP (better if you can use these '09 extensions). Therefore one *needs* to use EAP aka WPA Enterprise to get a secure WiFi. > > > > You have authentication frames that can be intercepted (so WPA > > > > passphrase can be bruteforced). > > > > > > Lots of things (such as TLS, ssh) can theoretically be brute forced - > > > the question is whether such brute forcing is sufficiently practical to > > > be a threat. I have seen nothing to indicate that properly configured > > > WPA2 can be realistically brute forced. > > > > For WPA2 it's not that hard really, assuming pre-shared key usage. > > Can be expensive (all those videocards and ASICs have their cost), but > > definitely doable. > > I'd be interested in seeing some real-world studies, or simply just a > mathematical analysis of how much hardware would be necessary to crack > a good WPA2 password. I've seen lots of sites explaining how to use > hashcat with a GPU, and various real-world tests on lists of hashed > passwords (e.g., [1]), but can you provide a serious analysis of the > practical cost, in time or hardware, of cracking a real-world WPA setup? Cost - Amazon will take 11c per hour for that VM that comes with NVIDIA Tesla videocard. Said hour is more than enough to bruteforce 8 character WPA passphrase with hashcat. > > You have several encryption algorithms, but: > > > > b) You may have a hardware that lack support for a good ones. > > > > > > I suppose, but my impression is that most hardware from the last few > > > years is fine. > > > > Cheap smartphones and tablets. Whatever they put instead of a proper > > This misses the point - we're comparing ethernet to wifi. Cheap > smartphones and tablets aren't usually going to support ethernet. You seem to misunderstand me. You have a network that's supposed to be secure. You have that small herd of assorted client devices, some of them are better, some are worse. Excommunicating "bad devices" from the network is usually out of question if said devices are owned by family members or trusted friends or, say, business associates. Due to the way APs work you cannot announce one set of encryption algorithms to one client, and different one to another, hence you bring down announced algorithms to the lowest common denominator. You can announce several, but it's bad for obvious reasons. You *could* get away with it with mutliple virtual APs, but that adds complexity. A classical example of one rotten apple spoiling the whole barrel. > > WiFi in printers (yep, I'm looking at you, HP). Oh, D-Link and Linksys. > > There are *always* some exceptions to "newer is the better" rule. > > D-Link and Linksys don't support WPA2-PSK with AES? If you mean "random hangs and CPU exhaustion" by trying to use CCMP - then yes, they do. But usually you're limited to TKIP if you need a glimpse of stability. Ones that I've seen, anyway. Maybe they hid good ones from me ;) Reco
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