It could well have been 100,000 Watts - there are FM transmitters in the UK up to 250kW but they're not exactly local stations. Megawatt range AM transmitters do exist too, the largest I know of being "Voice of Russia" at 2500kW which be recieved in the UK at night.
On the other hand he may have just been pulling numbers out of his arse.
I stand corrected, AM stereo exists (it just isn't used in the UK for some reason). I'd still expect some interference even at that range though due to the tiny power limits that these transmitters are subject to. No real way of testing that until someone makes an AM version though.
The main reason that these don't normally support AM is probably just that the sound quality is lower and it will only deliver mono audio. AM transmitters are usually simpler (and hence cheaper) to make so there has to be some kind of good reason behind it. It could also be that it's more difficult to construct an effective AM transmitting ariel in such a compact device.
Ah, sorry. It sounded like you weren't sure either way. The noise doesn't bother me that much any more (probably because my hearing is getting worse due to age/gigs) but I still can't sleep with it on or anything like that.
My grandfather worked as a TV engineer for many years so I've inherited a whole load of interesting stories. One example is a guy whose TV could never get a signal first thing in the morning but it was fine later in the afternoon. They had his TV apart looking for problems, after 3 days it was finally solved. The problem was his TV ariel was pointing slightly downwards and the transmitter was about 20 miles away on an island, he was only getting a signal when the tide was right for it to reflect off the surface of the sea.
RF radiation is nothing like nuclear radiation
Except, you know...the nuclear radiation that is RF radiation...which is all of it.
There are 3 forms of nuclear radiation, two of which are particles and have *nothing* in common with RF radiation whatsoever. Then there's gamma which is electromagnetic but have wavelengths about ten orders of magnitude shorter than microwave radiation. The energy per photon is hence around 10**10 times greater. You could argue that the total energy emmitted by a large microwave transmitter can be higher than that from a gamma source but this only effects its ability to heat things. To cause molecular changes many microwave photons would have to strike the same molecule on a small enough time that the energy is not re-radiated. In practise this is so unlikely as to never happen.
The cage certainly isn't perfect, but it's not the mesh at the front that is the problem. Most of the leakage occurs around the back of the oven and around the outside edges of the door. If you want some evidence that no significant radiation passes through the mesh calculate the wavelength of microwaves at 2.4GHz and compare to the mesh size. Now consider the effects of diffraction were any to pass through.
I can hear that too, only for TVs, not for monitors (one LCD I have hums but that's because of the dodgy backlight inverter). What you can hear is the flyback transformer vibrating due to a similar effect that causes power tranformers to give off a 50/60Hz hum. In this case the frequency is much higher and most people can't hear it. The exact value depends on weather you're TV is NTSC or PAL and on the framerate (25/30Hz). For 625 lines 25Hz which is the UK standard this frequency is 15625 Hz. It is purely an audio signal though and nothing to do with electromagnetic radiation.
It will just form the oxide layer anyway and impede current flow.
Aluminium oxide dissolves in sufficiently strong alkali (it's the method used to prepare aluminium parts for anodizing). I don't know if the electrolyte in the battery is sufficient to do this but that might be the explaination.
If you're in the UK you will be able to download it from here tonight. The link is for the lastest program so it will probably point to the scientology one once it has been broadcast.
The main reason the UK emergency number is 999 is because 1's (and to some extent other low numbers like 2's) are too easy to generate from random line noise, etc. Only now we also have the new European number 112 and virtually all of the exchanges here still accept pulse dialling so it wouldn't suprise me if it happened fairly often.
Not sure why, but an incandescent was lasting at most 3 months in my home.
Incandescents don't last much longer in my house either - turns out it's cos the main's voltage is a little on the high side. In the UK it's now supposed to be 230V (was 240V) and I routinely measure up to about 255V. That means resistive loads (such as incandescants) will dissipate about 23% more power* than they're designed for.
* approximating the bulb to have constant resistance, (255/230)^2 = 1.23
This was pretty much my first thought when I read the summery. IIRC the tensile strength of carbon nanotubes is more than sufficient to make the ribbon but up until now they have all been extremely short and thus difficult to make a ribbon from. I don't have the book on me at the moment so I can't check this figure but I think about 4mm was the point that it started to become feasible.
It's all discussed in the context of various real life and sci-fi gubs but if you go to about halfway down this page there's a pretty good analysis of the use of lasers as weapons.
The basic conclusion seems to be that the laser must be pulsed at a fairly specific frequency in order to do damage, and that some rather nice adaptive optics are needed to focus the beam on the target before it would work at all. The reason for the pulses is that each one would cause a small steam explosion tearing a relativly large hole, with sufficient time between each for the steam and debris to disperse
A large part of the problem with making effective man-portable laser weapons seems to be powering them, then again the laser rifle mentioned in the summery is not exactly lightweight
In my univeristy (UK) each student has 10Mbit connections to their rooms and are all behind a NAT. Ports 21 and 80 go through a proxy but there is outbound access on 443, 22 and a few others which can be used for tunnelling. There doesn't seem to be any real attempt to restrict internal network usage other than that if you persistantly saturate the link between buildings (and they notice so it'd probably have to be peak time or something) they can turn off your outlet. No p2p works to outside the campus but their only concern seems to be the bandwidth used.
As a physics student I get an account on one of their unix servers which is very useful for tunnelling through when the web proxy goes down. I could use that for p2p but chances are they'd notice pretty quick.
I like that idea, If it's etched into the glass it should be pretty permanant (well at least until some moron drops it;-)). The only downside I can see is the number needed to store the data. Using only the first stage should keep the cost down a lot though since all they're really doing is using a dvd burner with a much more powerful laser. I can't see any reason a glass master couldn't be read with a laser in a similar way to a DVD, no need for an electron microscope.
Similar story really - I bought a HP Colour Laserjet 5 from a friend about a year ago. It does A3 too but only in B&W (I rarely need A3 printing though) and it cost me £40. It gets fairly regular use but it's not quite photo quality so we still keep an inkjet around. As a bonus I've seen a full set of 4 toners on ebay for £15, for this printer they're not cartriges but bottles you pour in (or so I'm told, not had to do it yet). It's quite bulky but we just shoved it into a cupboard out of the way and hooked it up to the network.
I do that! Not really sure why (partly the recording my life thing) but occasionally it's useful. Sometimes I read through them when I get bored and I am always amazed how much stuff happens I don't remember just a few months later, kinda like re-reading a diary in some ways.
Not needing my most sensitive and important paper based ID easily to hand also means I can store it in a more secure location. The idea is that the card will become your most important form of ID, hence similar problems if you loose it.
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Gentlemen. We cannot allow a Broadband gap!
(Shamlessly ripped from Dr Strangelove)
It could well have been 100,000 Watts - there are FM transmitters in the UK up to 250kW but they're not exactly local stations. Megawatt range AM transmitters do exist too, the largest I know of being "Voice of Russia" at 2500kW which be recieved in the UK at night.
On the other hand he may have just been pulling numbers out of his arse.
I stand corrected, AM stereo exists (it just isn't used in the UK for some reason). I'd still expect some interference even at that range though due to the tiny power limits that these transmitters are subject to. No real way of testing that until someone makes an AM version though.
The main reason that these don't normally support AM is probably just that the sound quality is lower and it will only deliver mono audio. AM transmitters are usually simpler (and hence cheaper) to make so there has to be some kind of good reason behind it. It could also be that it's more difficult to construct an effective AM transmitting ariel in such a compact device.
Ah, sorry. It sounded like you weren't sure either way. The noise doesn't bother me that much any more (probably because my hearing is getting worse due to age/gigs) but I still can't sleep with it on or anything like that.
My grandfather worked as a TV engineer for many years so I've inherited a whole load of interesting stories. One example is a guy whose TV could never get a signal first thing in the morning but it was fine later in the afternoon. They had his TV apart looking for problems, after 3 days it was finally solved. The problem was his TV ariel was pointing slightly downwards and the transmitter was about 20 miles away on an island, he was only getting a signal when the tide was right for it to reflect off the surface of the sea.
There are 3 forms of nuclear radiation, two of which are particles and have *nothing* in common with RF radiation whatsoever. Then there's gamma which is electromagnetic but have wavelengths about ten orders of magnitude shorter than microwave radiation. The energy per photon is hence around 10**10 times greater. You could argue that the total energy emmitted by a large microwave transmitter can be higher than that from a gamma source but this only effects its ability to heat things. To cause molecular changes many microwave photons would have to strike the same molecule on a small enough time that the energy is not re-radiated. In practise this is so unlikely as to never happen.
The cage certainly isn't perfect, but it's not the mesh at the front that is the problem. Most of the leakage occurs around the back of the oven and around the outside edges of the door. If you want some evidence that no significant radiation passes through the mesh calculate the wavelength of microwaves at 2.4GHz and compare to the mesh size. Now consider the effects of diffraction were any to pass through.
I can hear that too, only for TVs, not for monitors (one LCD I have hums but that's because of the dodgy backlight inverter). What you can hear is the flyback transformer vibrating due to a similar effect that causes power tranformers to give off a 50/60Hz hum. In this case the frequency is much higher and most people can't hear it. The exact value depends on weather you're TV is NTSC or PAL and on the framerate (25/30Hz). For 625 lines 25Hz which is the UK standard this frequency is 15625 Hz. It is purely an audio signal though and nothing to do with electromagnetic radiation.
Aluminium oxide dissolves in sufficiently strong alkali (it's the method used to prepare aluminium parts for anodizing). I don't know if the electrolyte in the battery is sufficient to do this but that might be the explaination.
If you're in the UK you will be able to download it from here tonight. The link is for the lastest program so it will probably point to the scientology one once it has been broadcast.
The main reason the UK emergency number is 999 is because 1's (and to some extent other low numbers like 2's) are too easy to generate from random line noise, etc. Only now we also have the new European number 112 and virtually all of the exchanges here still accept pulse dialling so it wouldn't suprise me if it happened fairly often.
Incandescents don't last much longer in my house either - turns out it's cos the main's voltage is a little on the high side. In the UK it's now supposed to be 230V (was 240V) and I routinely measure up to about 255V. That means resistive loads (such as incandescants) will dissipate about 23% more power* than they're designed for.
* approximating the bulb to have constant resistance, (255/230)^2 = 1.23
This was pretty much my first thought when I read the summery. IIRC the tensile strength of carbon nanotubes is more than sufficient to make the ribbon but up until now they have all been extremely short and thus difficult to make a ribbon from. I don't have the book on me at the moment so I can't check this figure but I think about 4mm was the point that it started to become feasible.
It's all discussed in the context of various real life and sci-fi gubs but if you go to about halfway down this page there's a pretty good analysis of the use of lasers as weapons.
The basic conclusion seems to be that the laser must be pulsed at a fairly specific frequency in order to do damage, and that some rather nice adaptive optics are needed to focus the beam on the target before it would work at all. The reason for the pulses is that each one would cause a small steam explosion tearing a relativly large hole, with sufficient time between each for the steam and debris to disperse
A large part of the problem with making effective man-portable laser weapons seems to be powering them, then again the laser rifle mentioned in the summery is not exactly lightweight
In my univeristy (UK) each student has 10Mbit connections to their rooms and are all behind a NAT. Ports 21 and 80 go through a proxy but there is outbound access on 443, 22 and a few others which can be used for tunnelling. There doesn't seem to be any real attempt to restrict internal network usage other than that if you persistantly saturate the link between buildings (and they notice so it'd probably have to be peak time or something) they can turn off your outlet. No p2p works to outside the campus but their only concern seems to be the bandwidth used. As a physics student I get an account on one of their unix servers which is very useful for tunnelling through when the web proxy goes down. I could use that for p2p but chances are they'd notice pretty quick.
I like that idea, If it's etched into the glass it should be pretty permanant (well at least until some moron drops it ;-)). The only downside I can see is the number needed to store the data. Using only the first stage should keep the cost down a lot though since all they're really doing is using a dvd burner with a much more powerful laser. I can't see any reason a glass master couldn't be read with a laser in a similar way to a DVD, no need for an electron microscope.
Similar story really - I bought a HP Colour Laserjet 5 from a friend about a year ago. It does A3 too but only in B&W (I rarely need A3 printing though) and it cost me £40. It gets fairly regular use but it's not quite photo quality so we still keep an inkjet around. As a bonus I've seen a full set of 4 toners on ebay for £15, for this printer they're not cartriges but bottles you pour in (or so I'm told, not had to do it yet). It's quite bulky but we just shoved it into a cupboard out of the way and hooked it up to the network.
I do that! Not really sure why (partly the recording my life thing) but occasionally it's useful. Sometimes I read through them when I get bored and I am always amazed how much stuff happens I don't remember just a few months later, kinda like re-reading a diary in some ways.