This technique was used by MI5 and GCHQ as long ago as 1956. It was developed by Peter Wright, a former assistant director-general of MI5, and used to get the rotor wheel settings for a Hagelin crypto machine in the Egyptian embassy in London. The microphone was in a bugged telephone 2 feet away. He described the operation in his 1987 book, 'Spycatcher'.
The idea of giving students in a classroom buttons to push is hardly new. It has been around for at least 40 years. I first encountered it in 1974 at the BBC Engineering Training Centre. The British Post Office used the same idea for technical training as far back as the 1960s.
The idea is that a lecture can be broken into modules, and the lecturer can then ask multiple choice questions using the buttons to find out whether the students have understood the module. If he gets a sea of green lights on his console, he knows that most or all of the students understood it. If he gets lots of red lights, he knows he didn't get the module across very well and tries again. If a particular student does badly, he can be given extra assistance.
All of this was implemented in very simple electrical hardware - just switches and lamps.
There are a couple of good reasons for having anti-virus software on a unix/linux mail server, even though they don't get viruses. First, it can protect Windows email clients. Second, anti-virus software can also pick up things like phishing emails, which are platform-agnostic.
Fortunately, good quality free (speech and beer) anti-virus software is available from http://www.clamav.net/ - and it's packaged in many linux distros.
For all sorts of reasons, a PA mix often makes for a poorly balanced recording. It's a very hit and miss process.
To do it well needs a recording truck where someone can listen on speakers with a flat response, in an known acoustic similar to a living room, at a moderate sound level and without the HF attenuation of 100ft of humid air.
Even then, mixing a concert direct to stereo is a formidable craft skill. Normally it would be recorded to multitrack tape or disc and mixed down later.
American readers may be interested to learn that they - or at least their grandparents - paid for the construction of the Guardian telephone exchange under Manchester, and several others. It was a cold war NATO project to protect comms against atom bombs on the city centres. There were similar exchanges under London (Kingsway) and Birmingham (Anchor). They were built in the early 1950s, but are now obsolete. Although the underground exchanges have gone, the cable tunnels that run from these city centre locations to the ourskirts are still very much in use. Details of all of these and many other 'secret' underground structures in the UK can be found on the Subterranea Britannica web site.
The solution is to offer tiered services at different prices. My ISP (Andrews & Arnold) offers a choice of 'lite', 'standard' and 'all you can eat' DSL services at a choice of 512, 1024 or 2048 kb/s down (all 256 up) at prices ranging from GBP 27.95 to 235.00 per month. They can be found at http://sod.ms/ !
The American spelling of 'color' is true to the
original. The 'u' was introduced into the British
spelling relatively recently as a silly, pretentious affectation in the Victorian era.
I'm as offended by crass American arrogance and
presumption as almost everyone else in the rest of the world, but you've picked a duff example here.
Wrong. Specify "Arial,Helvetica,Geneva,sans-serif". The list should always end with one of the five generic font families.
Sorry, but at 244 grams your phone is a toaster
on
New All-In-One Nokia
·
· Score: 2
Two weeks ago I got rid of my 3-year old Nokia phone. It was a ludicrously clunky old thing by European standards, weighing in at 232 grams. I replaced it with a new Nokia 3210 phone (dual-band 900/1800 MHz GSM) which weighs 155 grams. (I just put them both on the kitchen scales.)
There were many other lighter models available in the shop, but they were too small for comfort IMHO - I would be frightened of losing them. I guess these weigh around 100 grams.
Konqueror 2.0, part of KDE 2.0, seems to be more
stable than Netscape/Mozilla, IMHO. As well as
all the (useful) features of Navigator/IE, it has
per-site configuration of cookies, Java and
JavaScript.
I have a 32-inch 100 Hz widescreen set and a Digital (Terrestrial) box, using the 625-line system (768 x 576 pixels). Digital gives better picture quality for widescreen broadcasts on widecreen displays, but for anything 4:3 it is no better than analogue, all things considered. In some ways digital is better (less noise, no chrom/lum crosstalk, higher chroma resolution) and in some ways worse (visible compression artefacts and naff mpeg-type audio).
In the US, which AFAIK doesn't have much if any widescreen TV yet, the only `benefit' of DTV that I can see is the extra channels.
The article talks of ``minute turbulences'' in ``commercial wavelengths''. It's difficult to divine the precise meaning of this, but I suspect it is talking about the effect of radio reflections rather than some subtle atmospheric thing. All aircraft reflect broadcast signals - this is what causes the rapid `flutter fading' on distant FM stations, or makes the TV picture go wobbly when a military jet flies over your house at 250 ft. (Yes, they do that here in the UK!) Radar exploits these echoes. Most aircraft have curved surfaces which scatter reflected RF in all directions, so they can be detected easily. The planar surfaces of stealth aircraft are designed to produce specular (ray-like) reflections, which will probably point somewhere other than the radar site. It may be that the Chinese are hoping that if a stealth plane is illuminated by a very large number of broadcast transmitter sites, the probability of getting a specular reflection to point at a given receiver site is increased in proportion to the number of such transmitters.
Because of the low transmitter powers, and the inherent vulnerability of any `quart-into-a-pint-pot' modulation scheme to impulsive noise ('cos of Shannon's Law), I get a lot of two-second freezes of the picture during thunderstorms, even though the signal strength is a good 12dB above threshold in normal conditions. Electrical interference can be a problem for the same reason, so you need a good outdoor antenna and double-screened (e.g. RG6 or CT100) co-ax cable. Having done that, it works very well most of the time.
Here in the UK, all TV is on UHF. In countries which use VHF, multipath is likely to be a bigger problem: COFDM is really neat at tackling it.
It may help if you just rearrange the cables, in order to minimise the area enclosed by the loop. This will minimise the amount of magnetic flux that can pass through it, which in turn minimises the current induced in the loop by stray 60 Hz magnetic fields. (A ground loop acts like a shorted secondary turn on a transformer.)
People have been electrocuted after lifting mains grounds to reduce audio hum loops. Please don't do it.
Slashdot Mirror
It's been done.
http://sod.ms/
An 1/8th inch stereo jack? Er ... that's 3.175 mm. There's no such thing. Did the poster mean a 3.5mm stereo jack?
This technique was used by MI5 and GCHQ as long ago as 1956. It was developed by Peter Wright, a former assistant director-general of MI5, and used to get the rotor wheel settings for a Hagelin crypto machine in the Egyptian embassy in London. The microphone was in a bugged telephone 2 feet away. He described the operation in his 1987 book, 'Spycatcher'.
The idea of giving students in a classroom buttons to push is hardly new. It has been around for at least 40 years. I first encountered it in 1974 at the BBC Engineering Training Centre. The British Post Office used the same idea for technical training as far back as the 1960s.
The idea is that a lecture can be broken into modules, and the lecturer can then ask multiple choice questions using the buttons to find out whether the students have understood the module. If he gets a sea of green lights on his console, he knows that most or all of the students understood it. If he gets lots of red lights, he knows he didn't get the module across very well and tries again. If a particular student does badly, he can be given extra assistance.
All of this was implemented in very simple electrical hardware - just switches and lamps.
There are a couple of good reasons for having anti-virus software on a unix/linux mail server, even though they don't get viruses. First, it can protect Windows email clients. Second, anti-virus software can also pick up things like phishing emails, which are platform-agnostic.
Fortunately, good quality free (speech and beer) anti-virus software is available from http://www.clamav.net/ - and it's packaged in many linux distros.
For all sorts of reasons, a PA mix often makes for a poorly balanced recording. It's a very hit and miss process.
To do it well needs a recording truck where someone can listen on speakers with a flat response, in an known acoustic similar to a living room, at a moderate sound level and without the HF attenuation of 100ft of humid air.
Even then, mixing a concert direct to stereo is a formidable craft skill. Normally it would be recorded to multitrack tape or disc and mixed down later.
Lindos Electronics make high-end pro-audio test equipment. They have done for over 25 years.
American readers may be interested to learn that they - or at least their grandparents - paid for the construction of the Guardian telephone exchange under Manchester, and several others. It was a cold war NATO project to protect comms against atom bombs on the city centres. There were similar exchanges under London (Kingsway) and Birmingham (Anchor). They were built in the early 1950s, but are now obsolete. Although the underground exchanges have gone, the cable tunnels that run from these city centre locations to the ourskirts are still very much in use. Details of all of these and many other 'secret' underground structures in the UK can be found on the Subterranea Britannica web site.
The solution is to offer tiered services at different prices. My ISP (Andrews & Arnold) offers a choice of 'lite', 'standard' and 'all you can eat' DSL services at a choice of 512, 1024 or 2048 kb/s down (all 256 up) at prices ranging from GBP 27.95 to 235.00 per month. They can be found at http://sod.ms/ !
The American spelling of 'color' is true to the original. The 'u' was introduced into the British spelling relatively recently as a silly, pretentious affectation in the Victorian era.
I'm as offended by crass American arrogance and presumption as almost everyone else in the rest of the world, but you've picked a duff example here.
Wrong. Specify "Arial,Helvetica,Geneva,sans-serif". The list should always end with one of the five generic font families.
There were many other lighter models available in the shop, but they were too small for comfort IMHO - I would be frightened of losing them. I guess these weigh around 100 grams.
Copyright is not intrinsically evil. Anyone who uses the GPL to protect their work against carpet-baggers understands that.
Konqueror 2.0, part of KDE 2.0, seems to be more stable than Netscape/Mozilla, IMHO. As well as all the (useful) features of Navigator/IE, it has per-site configuration of cookies, Java and JavaScript.
In the US, which AFAIK doesn't have much if any widescreen TV yet, the only `benefit' of DTV that I can see is the extra channels.
The article talks of ``minute turbulences'' in ``commercial wavelengths''. It's difficult to divine the precise meaning of this, but I suspect it is talking about the effect of radio reflections rather than some subtle atmospheric thing. All aircraft reflect broadcast signals - this is what causes the rapid `flutter fading' on distant FM stations, or makes the TV picture go wobbly when a military jet flies over your house at 250 ft. (Yes, they do that here in the UK!) Radar exploits these echoes. Most aircraft have curved surfaces which scatter reflected RF in all directions, so they can be detected easily. The planar surfaces of stealth aircraft are designed to produce specular (ray-like) reflections, which will probably point somewhere other than the radar site. It may be that the Chinese are hoping that if a stealth plane is illuminated by a very large number of broadcast transmitter sites, the probability of getting a specular reflection to point at a given receiver site is increased in proportion to the number of such transmitters.
Because of the low transmitter powers, and the inherent vulnerability of any `quart-into-a-pint-pot' modulation scheme to impulsive noise ('cos of Shannon's Law), I get a lot of two-second freezes of the picture during thunderstorms, even though the signal strength is a good 12dB above threshold in normal conditions. Electrical interference can be a problem for the same reason, so you need a good outdoor antenna and double-screened (e.g. RG6 or CT100) co-ax cable. Having done that, it works very well most of the time.
Here in the UK, all TV is on UHF. In countries which use VHF, multipath is likely to be a bigger problem: COFDM is really neat at tackling it.
There's some good background material on COFDM on the BBC Research Department web site.
People have been electrocuted after lifting mains grounds to reduce audio hum loops. Please don't do it.