The sparks that fly off metal objects like pop tart bags and CD's are caused by poor insulation in the microwave cavity.
Kinda, but not quite.
Sparks on metal objects is caused by uneven voltage developed on the surface of the object because of an uneven surface, uneven radiation pattern, or both.
Because microwaves are such high frequency and the wattages of most ovens is high (most are around 1 kilowatt), high voltages are easily developed and can leap short distances.
Once the spark leaps once, it ionizes the air along the path making subsequent arcs occur at lower voltage.
Once current flows, as in an arc of this type, the metal will heat up very rapidly and could easily burn paper. I suspect uneven radiation (or even minute flaws) of the metal strips in the bills caused arcing between them, which burned through the paper.
There's normally no insulation in the microwave cavity of the oven because the goal is to reflect the microwaves off ground (the metal surfaces surrounding the cavity) until they can be absorbed by water molecules, causing them to heat up, thus cooking the food.
This is why you are normally advised not to run the microwave oven with nothing in it: the microwaves can bounce around the oven and manage to heat the magnetron instead, causing it to burn out spectacularly.
On the 17th, at 09:14 GMT, winds were from 030 at 21 knots, gusting to 32 knots. Visibility was six statute miles with light rain and mist. The sky was overcast at 1200 feet.
Temporarily, for less than two hours, between 0900 to 1300 GMT, visibility will drop to 3 statue miles with moderate rain and mist and the ceiling will drop to 800 feet overcast.
From 14:00 to 21:00 GMT, winds will shift to be from 020 at 13 knots, gusting to 20 knots. Visibility will rise to 5 statute miles with light rain and mist. Sky will be overcast at 1200 feet.... etc. They're actually easy to read if you do it often enough. I can usually decode METAR faster than I can read an ordinary plain-english forecast.
I saw the tin can at the focus point of the dish. Wouldn't a Low Noise Block (LNB) converter be more efficient for signal transmission?
No, because a LNB facilitates reception, not transmission. The LNB takes a certain frequency range and mixes it with a much lower frequency signal, then boosts it so it can be transmitted over a reasonable distance on cheap coax.
Ok I understand the curvature of the Earth thing. But damnit! HAM Radios don't have to be line of site. Why the hell do I have to be within line of site of my friends house to reach his bandwidth!
I'm not sure if you're kidding or not, but I'll tell you the reason anyway.
It has a little to do with output power, but mostly to do with frequency. The higher in frequency you go the more readily the energy is absorbed by "stuff."
Ham operators use HF frequencies (loosely defined as about 7MHz - 30MHz). Those frequencies tend to be reflected and/or refracted by the atmosphere and they can "skip" over great distances. Once the signals reach the ground, they can bounce off the ground and skip again, leading to VERY great distances. If the atmosphere didn't help in this way, ham operators would too be limited to line-of-sight.
I thought having your charges read to you was one of the things they are supposed to do, much like your getting your one phone call.
Well, in a word, no.
The only thing required is that you be read your Miranda rights. Everything else is optional.
You can be detained for any reason at any time by anyone (yes, even private citizens can detain via citizen's arrest rights).
Police officers are held to a legal standard called "probable cause." This is not because they need it to perform an arrest, but because the arrest would not pass basic legal requirements to be a basis for a criminal charge.
There is absolutely no requirement that you be told why you are being arrested, but you do have to be told what the charges against you are when you are formally charged.
Don't confuse an arrest warrant and a a formal charged levied against you by a court. An arrest warrant simply means that, in a judge's opinion, a sufficient amount of evidence has been presented in an appropriate way to support the strong possibility, aka, "probable cause," that you have committed a crime.
Once you are arraigned, then you are charged and you will hear the charges levied against you by the court.
Since OpenDarwin is being ported to the platform, I'd be inclined to believe that just plain Darwin (MacOS X) would NOT run on the hardware as-is and therefore you can't run MacOS X on the system.
When the OpenDarwin port is complete, you *may* be able to install MacOS X on a drive then overlay OpenDarwin on top of that and then be able to boot it onto the clone.
Remember that Macs use Open Firmware to boot, so this clone would need either Open Firmware, something compliant to the spec, or hooks to make it work (or some combination of all three).
Considering the cheapest 12" PowerBooks start at around $1200, I'd say the Apple premium isn't too bad. Granted, that's WAY more than these clones, but then you don't have to deal with the fuss of trying to shim MacOS X onto a non-native platform.
Shouldn't packet switching and TDMA like technologies make the walkie-talkie limitations irrelevant?
Wireless providers are not rolling this out to save bandwidth... they are rolling it out to court business users utilizing trunked (or even conventional) radio systems.
The providers see this as a way of being the "killer app" for dispatch-based businesses that rely on rapid easy broadcast communications.
Trunked radio systems are limited by a service area and reception issues. Cellular wireless providers already have blanket networks in urban areas (for the most part) with coverage extending way out into the rural areas.
In short, businesses can dump trunked radio in favor of this for less per month and get more coverage.
On an unrelated note, what the heck is up with Slashdot lately? It's sluggish as all hell!
Being "colorblind," I'm amazed at how misunderstood it is!
The site you give only shows some of the most severe cases... most people who have color perception problems (as they typically are not blind to color) see almost all colors properly. The examples given are a complete *absense* of the indicated cones, not the typical "color shift" problem, where the red or green (and sometimes blue) cones have the wrong pigment in them and respond to slightly different colors.
This is the type of blindness I have... my red cones are just a slightly "wrong" color red.
Because of this, I have trouble decriminating between very light greens and yellow. Orange and green, if close enough on the color wheel, can also be confusing. UPS trucks look forest green to me in certain types of light (especially sunset) and bright brown in others.
HOWEVER, I can identify almost all colors in a controlled environment.
To give a good example most people could relate with... in MacOS X (my OS of choice:) ) the green and yellow interface buttons (for minimize and maximize) look like SIMILIAR colors, but I can distinguish between them.
Say someone flashed me a card that was that color yellow and asked me whether it was yellow or green. I'd probably be right about 75% of the time, whereas someone with normal color vision would get it right every time.
I have somewhat average color blindness, meaning that most people have about as much trouble as I do.
However, a smaller percentage, about 3%, have very severe problems where they almost literally cannot see color at all. Greens appear black, reds are grey or pink, and blue and violet are just purply.
Even as obscure as this seems, it could easily kill you if delivered in just the right way.
It takes just MILLIamps to stop your heart. If you had just gotten out of salt water (or were sweaty...) and grabbed the laptop in one hand and a grounded water pipe with the other and your phone rang, it could potentially kill you just like that.
I'd think people with pacemakers would be even more vulnerable, but I don't know enough about them to comment further.
Sounds like Sony grounded the phone line to the laptop chassis, which is then grounded (probably) to the negative DC end of the power supply which is in turn grounded to common and/or ground on the wall socket. If you disconnect the power and hold the laptop and are then grounded in some way via holding a faucet or something you'd be the return path for the ring voltage.
The fix might be to run it through some sort of heavy resistance to reduce the voltage to something negligible in this situation.
I mean no offense by any of this... hopefully you'll take it constructively.
First, I listened to the ad on the website... I'd assume it was produced by the station itself and frankly, it's horrible. It generates no excitement and it isn't catchy enough to stick out of the crowd of other ads. In short, few people even heard the ad. I did radio work for many years and I think you were screwed by the station production people. That ad could have been formatted in a dozen other ways and had more impact.
Second, you're advertising on the wrong station. "The Link" looks like a hot AC station and your music just doesn't fit into that demographic. Have you tried a college station? Send them a gratis CD and see if they play it.
Find a station that plays something similar... I'd call it easy listening or maybe even jazz if I had to put it in a genre, but maybe you know better where you want to head with it. Once you've found your station, toss out some teaser ads and see what gets caught in the net.
Good luck!
Re:maintaining the shape of the original waveform
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AAC vs. OGG vs. MP3
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· Score: 1
That is the whole point of the graph, the changes in the compressed waveform dictate SOUND changes. If you can't understand that, I suggest you look at the article once again.
*sigh* I guess you can lead a horse to water...
All the graph is showing us is where the highest level of frequency loss is.
If you take a five minute WAV, for example, and run it through a spectrum analyzer, it's going to show you the average sound level, in dB, over five minutes from a lower limit of frequency X to an upper limit of frequency Y.
If you analyze a the same sample, but encoded with a psychoacoustic scheme, that same graph is only going to show you what frequencies the encoder dropped most often as a consequence of its psychoacoustic model.
So, in essence, all your graph is showing is the preference of the model for one frequency over another.
If you notice in your graphs, all three encoding systems drop off above about 15kHz. This is because 10kHz - 20kHz are the most easily "masked" frequencies to the human ear.
But this doesn't tell us the absolutely most important part of a psychoacoustic encoding scheme (and ask anyone who works on them if you don't believe me): does it sound good? does it remove what people won't hear and keep what people will?
Re:maintaining the shape of the original waveform
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AAC vs. OGG vs. MP3
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· Score: 2, Insightful
We compared all the lossy formats to a wav ripped straight from the CD.
It doesn't matter!
Spectrum analysis of a perceptual coding system is useless. The whole idea behind perceptual coding is that certain types of sounds mask others, so therefore you can avoid encoding the masked sounds.
The waveforms will always be different... the better the psycoacoustic model the more the waveform will differ for the same PERCEIVED quality.
But that's not the point... does it SOUND the same to the average listener? Does the perceived quality diminish? Does the audio suffer NOTICABLE artifacts that irritate the listener?
No matter what scheme you use, the answer to all of these questions will be "yes" to some people. But how many people say "yes?"
Each person's interpretation of audio is different... some people are tone deaf, others have a very high sensitivity to artifacts, and yet others are somewhere in the middle.
Spectrum analysis tells you nothing about how well a codec encodes for the human ear because the analyzer is FAR more sensitive.
A passive repeater is two tuned high-gain antennas connected by a length of high-quality coax (or other transmission line).
You put the exterior antenna in an optimum position for transmit/receive to the cellular antenna (perhaps even using a directional design such as a Yagi) and place the interior antenna in a strategic location for maximum internal coverage.
There IS some loss in this design, but the idea is to make up for it in the gain of the antennas (especially the external one).
Best of all, this design requires no power (as it is completely passive) and if you're handy with antenna design, you could whip the whole thing together on a thin budget.
Re:Privacy issue explained
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NYT on RFID Tags
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· Score: 4, Insightful
Although your points are valid, I really don't think this is a hot an issue as people make it out to be.
Your every action can be, or nearly can be, tracked by other means, so what difference does it make if they put an RF inventory tag on your pants? Does some law mandate you can't remove these tags? Granted, it's highly inconvenient to remove them, but possible none-the-less.
These tags are incredibly low power and can only be usefully read at distances typical to inventory: a couple of clear football fields at best. With all of your clothes in your closet, someone would have to be within a city block to even trigger the things and reading them would be even harder.
As for an uber-database... remembering each RFID tag and what it was associated with is trivial, as is associating it with you when you purchase it. But then what? They already gather that information anyway. Even if you pay with cash, there's always a camera and don't think for one second they can't reassociate that register's receipts with the images on tape.
I just don't see the privacy threat here... what's K-Mart going to do, drive around the neighborhood pinging houses to see if you've got some of their pants?
The government could conceivably slap some database together for all this stuff, but the amount of storage required would be massive for a minimal amount of gain. They can already figure out what you bought and where now anyway.
An automobile mechanic is certified and licensed because there are safety issues that can be fatal when a mechanic performs their duties improperly.
Similarly, a hair stylist has sanitation concerns that must be met to provide a germ-free and safe environment.
A computer technician normally troubleshoots and diagnoses systems that do not have concerns of this type.
Granted, there are occasions when a system is critical to the functioning of a system of this type, such as elevators, but most of those functions are licensed anyway, so the technology must be certified, rather than the technician.
It looks like channel 12 WKRC Cincinnati is an analog television station, not a digital one. I was really interested to find out the specifics behind subchannel broadcasting on a DTV signal... oh well.
If it is indeed an analog station, it's likely VRTI internet or Vertical Re-Trace Interval. The VRTI is the period of time when the scan-gun in your telvision dims (or turns off) and jumps from the last line in the picture to the first line in order to begin painting the next interlaced frame. This interval happens sixty times a second and can carry nearly anything if modulated right. I don't know what the resulting bit-rate would be, though.
It could also be a subcarrier within the bandwidth for channel 12, but I can't see them getting those kind of speeds with it (although its possible).
I remember reading about this many years ago and never seeing it put to real use... perhaps this is the first example?
your bandwidth for data is DIRECTLY coupled to the frequency of transmission.
No, it isn't. You could easily modulate a 1MHz carrier with a 10MHz signal. You'd lose your lower sideband because you don't have enough space below, but your upper sideband would happily carry the signal. If your deviation were set low enough, you could even get away with doing this via FM, but your modulator and detector would have to be unbelievably accurate and sensitive.
Granted, the filtering would be a real bitch, the thing would be very unstable, and designing a receiver to figure all of this out would be a pain, but the theory lets you do it.
Think of it as a mixture of signals versus an absolute modulation... I think that's where you're getting stuck. The peaks of the RF signal don't carry information... it's the alteration of that wave that does.
Modulating a 1MHz AM carrier with a 100kHz signal renders three signals:.900MHz, 1MHz, and 1.1MHz. The sidebands are far below the carrier from an intensity standpoint, but they carry the information. The carrier is a convenient reference to decode the sidebands.
Television signals routinely use only the upper sideband plus a carrier to save bandwidth. This is called Vestigal Sideband or VSB.
Yes, actually, high bandwidth things do better at higher frequencies for technical reasons. It includes antenna and circuitry issues. If you put a 25MHz wide signal at 50MHz, you will need to have circuits that deal with everything from 37 to 63 MHz (and an antenna to do the same). That's almost an octave.
I knew there had to be a technician out there somwhere.:)
Yes, I know this... but the original message was discussing how much MORE bandwidth a given signal would require if you pushed it lower in the spectrum. This simply isn't true.
25MHz is a huge bandwidth to deal with at much lower frequencies because of resonance concerns (and filtering, amplification, and everything else).
You're right about it being a bad idea, though... lots of those who dwell way out in the rural areas use extreme measures to receive television broadcasts.
In addition, propogation changes could easily push a channel 2 signal nearly anywhere at the peak of a sunspot cycle. Part 15 devices would easily be drowned out by atmospheric skip. The FCC is already seeing this problem (and I think it was carried by Slashdot) in situations where HDTV signals were interfering with existing fixed mobile wireless services in other parts of the country due to ducting.
and carry LESS information than 2.4Ghz the amount of information you are able to carry in a frequency channel is DIRECTLY coupled with the frequency and width of the channel you use. in the 50MHZ range where channels 2 and 3 reside you CANNOT transmit very much without using alot of the spectrum with a wide channel. I.E. you are using tons of frequencies to transmit the same information that is able to be transmitted on a few in the higher frequencies. and to do this you need Gobs more power.
Huh? The bandwidth required is not dependent on frequency. A television channel takes 6MHz no matter where you put it in the spectrum... 50MHz, 400MHz, 1.2GHz, etc.
The power required for an equivalent coverage area varies, yes, but the bandwidth required does not. If you modulate a 10MHz carrier with a television signal, you'll suck up 6MHz of space.
I think this is a common misconception because of the way the spectrum is currently laid out. The reason that high-bandwidth items are higher in frequency is simply that they were developed later in history than other uses. Therefore, they got higher frequencies because those below it were allocated and didn't provide enough available space for that particular purpose.
If you could find a 25MHz chunk of bandwidth at any frequency you could run 802.11 stuff. Your power requirements would vary, of course, and your antenna would change size (and perhaps shape).
It's not magical. we use 2.4ghz because at low powers and small channel widths we can spew lots of information... as your frequency goes down the wider you need to be and the more powerful you need to be.
That is just wrong. We use 2.4GHz because that's where the available spectrum is, not because there's something magical about 2.4GHz itself.
The only thing special about higher frequencies versus lower ones is propogation concerns (higher frequencies tend to go less distance with an equivalent power output) and antenna design.
This is pure genius folks... it's like using Microsoft's own stuff against them.
I know at least ten Mac users who have said that they keep a Winblows box around to "play games."
VirtualPC is handy, but it just plain sucks when it comes to doing high-end graphics (or, better said, just plain doesn't do high-end graphics).
Everyone is saying its endorsing a Microsoft "standard," but if you think about it it could take people off the Windows desktop, which is really our goal anyway.
So Microsoft gets to license a high-speed graphics library. So it sorta endorses the XBox. Who cares... they don't have monopolies in these areas.
First things first... lots of people are saying that ethernet doesn't require a ground. That's WRONG... a ground is always required, especially on transmission lines like ethernet cables. However, CAT5 is a balanced transmission line and shielding isn't all that important unless you're running the cable through an environment likely to disrupt this balance.
Second, the type of boat you're on makes a big difference. If you're on a metal hulled boat (or a boat with a metal mast or other convenient absolute ground), you're ground doesn't float... the water is ground. Salt water is especially good as a ground reference.
If you're in a fiberglass boat, the whole vessel is floating above ground. See if you can find a metal object (preferably brass or other non-oxidizing metal) always submerged and use it as your ship's ground.
Either way, the easy answer is don't worry about grounding the shield.
If you run into problems with data corruption (or want to prevent such problems), you should ground BOTH sides of the shield. On long cable runs (longer than a half-wave at your operating frequency) you should ground only ONE side. The hub-side is the best to ground as it is already the central network point... so making it the central grounding point makes sense as well.
The BEST solution is to use something called telescoping grounds. In a telescoping ground, both ends are grounded, but to different shields. Both shields are independent and isolated from one another and overlap for the length of the cable. This prevents common-mode currents on both components and avoids ground-loops at the same time. Professional audio cables use this technique often.
Another option you may not have considered is wireless. With a wireless network, the only ground that's important is that of the base station (for efficiency's sake). The client devices have their own ground reference and its relationship to the base station isn't important.
In the PanIP complaint, they demand a trial by jury. I can't imagine any (competent) jury in the United States that would award anything to PanIP for this.
It's almost as if they were awarded a patent for a device that absorbs nasal discharge via a paper wicking system. An ingenious idea, certainly, but an obvious one.
As far as I know, DirecTV doesn't put a lot of error correction into their signals... loss of a block of data just scrambles up your picture.
You're forgetting something, though... a digital signal takes up MUCH less space than an analog one, especially when you're encoding voice or music (MP3 or Vorbis, anyone?). Since the signal is much smaller, you can encode error correction in the remaining bandwidth.
This means that what you're listening to through the speakers isn't a real-time signal... it's delayed slightly because you want an opportunity to not only receive the primary signal but the redundant error-correction stream as well.
If you were to interleave all of this data over a period of 30 seconds, you could conceivably have a drop-out of about that long in the signal and still have full-quality audio playing out the speakers.
Of course, if your signal drop-out exceeds the available correction data, you're right in that you'd get nothing (or something other than static).
Seeing as I'm a "color deficient" individual, I just wanted to point out that the majority of people who suffer from some sort of color vision anomaly have absolutely no difficulty in determining which wire is the red one (or green one, etc).
There has been the rare occasion where I can confuse red and brown or yellow and green wires in my electronics projects, but only when the wires are so tiny magnification is almost a necessity anyway. With magnification, I can pick out the correct color.
I am green-weak, meaning that I see fewer shades of green than the average Joe, but I see saturated colors just fine. It's only undersaturated (too dark or too light... pastel) colors that give me problems.
Oddly, those with green weakness can confuse reds as well... this is because the green sensitive cells in your eye are not so much to see green as to differentiate it from red.
Most Police departments nowadays use the Munsell D-15 test for color vision screening. This is a more "real world" color test and most people with common red/green deficiencies (like me) can pass it. It is only people who simply are completely unable to see a color group (such as red or green) that fail.
The old method, which is to use isochromatic random dot fields (the ones where you must tell the examiner what number or figure you see), is so sensitive some people with completely normal color vision will fail.
Slashdot Mirror
The sparks that fly off metal objects like pop tart bags and CD's are caused by poor insulation in the microwave cavity.
Kinda, but not quite.
Sparks on metal objects is caused by uneven voltage developed on the surface of the object because of an uneven surface, uneven radiation pattern, or both.
Because microwaves are such high frequency and the wattages of most ovens is high (most are around 1 kilowatt), high voltages are easily developed and can leap short distances.
Once the spark leaps once, it ionizes the air along the path making subsequent arcs occur at lower voltage.
Once current flows, as in an arc of this type, the metal will heat up very rapidly and could easily burn paper. I suspect uneven radiation (or even minute flaws) of the metal strips in the bills caused arcing between them, which burned through the paper.
There's normally no insulation in the microwave cavity of the oven because the goal is to reflect the microwaves off ground (the metal surfaces surrounding the cavity) until they can be absorbed by water molecules, causing them to heat up, thus cooking the food.
This is why you are normally advised not to run the microwave oven with nothing in it: the microwaves can bounce around the oven and manage to heat the magnetron instead, causing it to burn out spectacularly.
you can't photocopy coins silly
Well, you can, but only the dumbest person at Taco Bell would take them.
BZZT. Try again.
... etc. They're actually easy to read if you do it often enough. I can usually decode METAR faster than I can read an ordinary plain-english forecast.
On the 17th, at 09:14 GMT, winds were from 030 at 21 knots, gusting to 32 knots. Visibility was six statute miles with light rain and mist. The sky was overcast at 1200 feet.
Temporarily, for less than two hours, between 0900 to 1300 GMT, visibility will drop to 3 statue miles with moderate rain and mist and the ceiling will drop to 800 feet overcast.
From 14:00 to 21:00 GMT, winds will shift to be from 020 at 13 knots, gusting to 20 knots. Visibility will rise to 5 statute miles with light rain and mist. Sky will be overcast at 1200 feet.
I saw the tin can at the focus point of the dish. Wouldn't a Low Noise Block (LNB) converter be more efficient for signal transmission?
No, because a LNB facilitates reception, not transmission. The LNB takes a certain frequency range and mixes it with a much lower frequency signal, then boosts it so it can be transmitted over a reasonable distance on cheap coax.
Ok I understand the curvature of the Earth thing. But damnit! HAM Radios don't have to be line of site. Why the hell do I have to be within line of site of my friends house to reach his bandwidth!
I'm not sure if you're kidding or not, but I'll tell you the reason anyway.
It has a little to do with output power, but mostly to do with frequency. The higher in frequency you go the more readily the energy is absorbed by "stuff."
Ham operators use HF frequencies (loosely defined as about 7MHz - 30MHz). Those frequencies tend to be reflected and/or refracted by the atmosphere and they can "skip" over great distances. Once the signals reach the ground, they can bounce off the ground and skip again, leading to VERY great distances. If the atmosphere didn't help in this way, ham operators would too be limited to line-of-sight.
I thought having your charges read to you was one of the things they are supposed to do, much like your getting your one phone call.
Well, in a word, no.
The only thing required is that you be read your Miranda rights. Everything else is optional.
You can be detained for any reason at any time by anyone (yes, even private citizens can detain via citizen's arrest rights).
Police officers are held to a legal standard called "probable cause." This is not because they need it to perform an arrest, but because the arrest would not pass basic legal requirements to be a basis for a criminal charge.
There is absolutely no requirement that you be told why you are being arrested, but you do have to be told what the charges against you are when you are formally charged.
Don't confuse an arrest warrant and a a formal charged levied against you by a court. An arrest warrant simply means that, in a judge's opinion, a sufficient amount of evidence has been presented in an appropriate way to support the strong possibility, aka, "probable cause," that you have committed a crime.
Once you are arraigned, then you are charged and you will hear the charges levied against you by the court.
Since OpenDarwin is being ported to the platform, I'd be inclined to believe that just plain Darwin (MacOS X) would NOT run on the hardware as-is and therefore you can't run MacOS X on the system.
When the OpenDarwin port is complete, you *may* be able to install MacOS X on a drive then overlay OpenDarwin on top of that and then be able to boot it onto the clone.
Remember that Macs use Open Firmware to boot, so this clone would need either Open Firmware, something compliant to the spec, or hooks to make it work (or some combination of all three).
Considering the cheapest 12" PowerBooks start at around $1200, I'd say the Apple premium isn't too bad. Granted, that's WAY more than these clones, but then you don't have to deal with the fuss of trying to shim MacOS X onto a non-native platform.
Shouldn't packet switching and TDMA like technologies make the walkie-talkie limitations irrelevant?
Wireless providers are not rolling this out to save bandwidth... they are rolling it out to court business users utilizing trunked (or even conventional) radio systems.
The providers see this as a way of being the "killer app" for dispatch-based businesses that rely on rapid easy broadcast communications.
Trunked radio systems are limited by a service area and reception issues. Cellular wireless providers already have blanket networks in urban areas (for the most part) with coverage extending way out into the rural areas.
In short, businesses can dump trunked radio in favor of this for less per month and get more coverage.
On an unrelated note, what the heck is up with Slashdot lately? It's sluggish as all hell!
Being "colorblind," I'm amazed at how misunderstood it is!
:) ) the green and yellow interface buttons (for minimize and maximize) look like SIMILIAR colors, but I can distinguish between them.
The site you give only shows some of the most severe cases... most people who have color perception problems (as they typically are not blind to color) see almost all colors properly. The examples given are a complete *absense* of the indicated cones, not the typical "color shift" problem, where the red or green (and sometimes blue) cones have the wrong pigment in them and respond to slightly different colors.
This is the type of blindness I have... my red cones are just a slightly "wrong" color red.
Because of this, I have trouble decriminating between very light greens and yellow. Orange and green, if close enough on the color wheel, can also be confusing. UPS trucks look forest green to me in certain types of light (especially sunset) and bright brown in others.
HOWEVER, I can identify almost all colors in a controlled environment.
To give a good example most people could relate with... in MacOS X (my OS of choice
Say someone flashed me a card that was that color yellow and asked me whether it was yellow or green. I'd probably be right about 75% of the time, whereas someone with normal color vision would get it right every time.
I have somewhat average color blindness, meaning that most people have about as much trouble as I do.
However, a smaller percentage, about 3%, have very severe problems where they almost literally cannot see color at all. Greens appear black, reds are grey or pink, and blue and violet are just purply.
Even as obscure as this seems, it could easily kill you if delivered in just the right way.
It takes just MILLIamps to stop your heart. If you had just gotten out of salt water (or were sweaty...) and grabbed the laptop in one hand and a grounded water pipe with the other and your phone rang, it could potentially kill you just like that.
I'd think people with pacemakers would be even more vulnerable, but I don't know enough about them to comment further.
Sounds like Sony grounded the phone line to the laptop chassis, which is then grounded (probably) to the negative DC end of the power supply which is in turn grounded to common and/or ground on the wall socket. If you disconnect the power and hold the laptop and are then grounded in some way via holding a faucet or something you'd be the return path for the ring voltage.
The fix might be to run it through some sort of heavy resistance to reduce the voltage to something negligible in this situation.
I mean no offense by any of this... hopefully you'll take it constructively.
First, I listened to the ad on the website... I'd assume it was produced by the station itself and frankly, it's horrible. It generates no excitement and it isn't catchy enough to stick out of the crowd of other ads. In short, few people even heard the ad. I did radio work for many years and I think you were screwed by the station production people. That ad could have been formatted in a dozen other ways and had more impact.
Second, you're advertising on the wrong station. "The Link" looks like a hot AC station and your music just doesn't fit into that demographic. Have you tried a college station? Send them a gratis CD and see if they play it.
Find a station that plays something similar... I'd call it easy listening or maybe even jazz if I had to put it in a genre, but maybe you know better where you want to head with it. Once you've found your station, toss out some teaser ads and see what gets caught in the net.
Good luck!
That is the whole point of the graph, the changes in the compressed waveform dictate SOUND changes. If you can't understand that, I suggest you look at the article once again.
*sigh* I guess you can lead a horse to water...
All the graph is showing us is where the highest level of frequency loss is.
If you take a five minute WAV, for example, and run it through a spectrum analyzer, it's going to show you the average sound level, in dB, over five minutes from a lower limit of frequency X to an upper limit of frequency Y.
If you analyze a the same sample, but encoded with a psychoacoustic scheme, that same graph is only going to show you what frequencies the encoder dropped most often as a consequence of its psychoacoustic model.
So, in essence, all your graph is showing is the preference of the model for one frequency over another.
If you notice in your graphs, all three encoding systems drop off above about 15kHz. This is because 10kHz - 20kHz are the most easily "masked" frequencies to the human ear.
But this doesn't tell us the absolutely most important part of a psychoacoustic encoding scheme (and ask anyone who works on them if you don't believe me): does it sound good? does it remove what people won't hear and keep what people will?
We compared all the lossy formats to a wav ripped straight from the CD.
It doesn't matter!
Spectrum analysis of a perceptual coding system is useless. The whole idea behind perceptual coding is that certain types of sounds mask others, so therefore you can avoid encoding the masked sounds.
The waveforms will always be different... the better the psycoacoustic model the more the waveform will differ for the same PERCEIVED quality.
But that's not the point... does it SOUND the same to the average listener? Does the perceived quality diminish? Does the audio suffer NOTICABLE artifacts that irritate the listener?
No matter what scheme you use, the answer to all of these questions will be "yes" to some people. But how many people say "yes?"
Each person's interpretation of audio is different... some people are tone deaf, others have a very high sensitivity to artifacts, and yet others are somewhere in the middle.
Spectrum analysis tells you nothing about how well a codec encodes for the human ear because the analyzer is FAR more sensitive.
You could use a passive repeater for this...
A passive repeater is two tuned high-gain antennas connected by a length of high-quality coax (or other transmission line).
You put the exterior antenna in an optimum position for transmit/receive to the cellular antenna (perhaps even using a directional design such as a Yagi) and place the interior antenna in a strategic location for maximum internal coverage.
There IS some loss in this design, but the idea is to make up for it in the gain of the antennas (especially the external one).
Best of all, this design requires no power (as it is completely passive) and if you're handy with antenna design, you could whip the whole thing together on a thin budget.
Although your points are valid, I really don't think this is a hot an issue as people make it out to be.
Your every action can be, or nearly can be, tracked by other means, so what difference does it make if they put an RF inventory tag on your pants? Does some law mandate you can't remove these tags? Granted, it's highly inconvenient to remove them, but possible none-the-less.
These tags are incredibly low power and can only be usefully read at distances typical to inventory: a couple of clear football fields at best. With all of your clothes in your closet, someone would have to be within a city block to even trigger the things and reading them would be even harder.
As for an uber-database... remembering each RFID tag and what it was associated with is trivial, as is associating it with you when you purchase it. But then what? They already gather that information anyway. Even if you pay with cash, there's always a camera and don't think for one second they can't reassociate that register's receipts with the images on tape.
I just don't see the privacy threat here... what's K-Mart going to do, drive around the neighborhood pinging houses to see if you've got some of their pants?
The government could conceivably slap some database together for all this stuff, but the amount of storage required would be massive for a minimal amount of gain. They can already figure out what you bought and where now anyway.
An automobile mechanic is certified and licensed because there are safety issues that can be fatal when a mechanic performs their duties improperly.
Similarly, a hair stylist has sanitation concerns that must be met to provide a germ-free and safe environment.
A computer technician normally troubleshoots and diagnoses systems that do not have concerns of this type.
Granted, there are occasions when a system is critical to the functioning of a system of this type, such as elevators, but most of those functions are licensed anyway, so the technology must be certified, rather than the technician.
It looks like channel 12 WKRC Cincinnati is an analog television station, not a digital one. I was really interested to find out the specifics behind subchannel broadcasting on a DTV signal... oh well.
If it is indeed an analog station, it's likely VRTI internet or Vertical Re-Trace Interval. The VRTI is the period of time when the scan-gun in your telvision dims (or turns off) and jumps from the last line in the picture to the first line in order to begin painting the next interlaced frame. This interval happens sixty times a second and can carry nearly anything if modulated right. I don't know what the resulting bit-rate would be, though.
It could also be a subcarrier within the bandwidth for channel 12, but I can't see them getting those kind of speeds with it (although its possible).
I remember reading about this many years ago and never seeing it put to real use... perhaps this is the first example?
your bandwidth for data is DIRECTLY coupled to the frequency of transmission.
.900MHz, 1MHz, and 1.1MHz. The sidebands are far below the carrier from an intensity standpoint, but they carry the information. The carrier is a convenient reference to decode the sidebands.
No, it isn't. You could easily modulate a 1MHz carrier with a 10MHz signal. You'd lose your lower sideband because you don't have enough space below, but your upper sideband would happily carry the signal. If your deviation were set low enough, you could even get away with doing this via FM, but your modulator and detector would have to be unbelievably accurate and sensitive.
Granted, the filtering would be a real bitch, the thing would be very unstable, and designing a receiver to figure all of this out would be a pain, but the theory lets you do it.
Think of it as a mixture of signals versus an absolute modulation... I think that's where you're getting stuck. The peaks of the RF signal don't carry information... it's the alteration of that wave that does.
Modulating a 1MHz AM carrier with a 100kHz signal renders three signals:
Television signals routinely use only the upper sideband plus a carrier to save bandwidth. This is called Vestigal Sideband or VSB.
Yes, actually, high bandwidth things do better at higher frequencies for technical reasons. It includes antenna and circuitry issues. If you put a 25MHz wide signal at 50MHz, you will need to have circuits that deal with everything from 37 to 63 MHz (and an antenna to do the same). That's almost an octave.
:)
I knew there had to be a technician out there somwhere.
Yes, I know this... but the original message was discussing how much MORE bandwidth a given signal would require if you pushed it lower in the spectrum. This simply isn't true.
25MHz is a huge bandwidth to deal with at much lower frequencies because of resonance concerns (and filtering, amplification, and everything else).
You're right about it being a bad idea, though... lots of those who dwell way out in the rural areas use extreme measures to receive television broadcasts.
In addition, propogation changes could easily push a channel 2 signal nearly anywhere at the peak of a sunspot cycle. Part 15 devices would easily be drowned out by atmospheric skip. The FCC is already seeing this problem (and I think it was carried by Slashdot) in situations where HDTV signals were interfering with existing fixed mobile wireless services in other parts of the country due to ducting.
and carry LESS information than 2.4Ghz the amount of information you are able to carry in a frequency channel is DIRECTLY coupled with the frequency and width of the channel you use. in the 50MHZ range where channels 2 and 3 reside you CANNOT transmit very much without using alot of the spectrum with a wide channel. I.E. you are using tons of frequencies to transmit the same information that is able to be transmitted on a few in the higher frequencies. and to do this you need Gobs more power.
Huh? The bandwidth required is not dependent on frequency. A television channel takes 6MHz no matter where you put it in the spectrum... 50MHz, 400MHz, 1.2GHz, etc.
The power required for an equivalent coverage area varies, yes, but the bandwidth required does not. If you modulate a 10MHz carrier with a television signal, you'll suck up 6MHz of space.
I think this is a common misconception because of the way the spectrum is currently laid out. The reason that high-bandwidth items are higher in frequency is simply that they were developed later in history than other uses. Therefore, they got higher frequencies because those below it were allocated and didn't provide enough available space for that particular purpose.
If you could find a 25MHz chunk of bandwidth at any frequency you could run 802.11 stuff. Your power requirements would vary, of course, and your antenna would change size (and perhaps shape).
It's not magical. we use 2.4ghz because at low powers and small channel widths we can spew lots of information... as your frequency goes down the wider you need to be and the more powerful you need to be.
That is just wrong. We use 2.4GHz because that's where the available spectrum is, not because there's something magical about 2.4GHz itself.
The only thing special about higher frequencies versus lower ones is propogation concerns (higher frequencies tend to go less distance with an equivalent power output) and antenna design.
The bandwidth required does not change.
This is pure genius folks... it's like using Microsoft's own stuff against them.
I know at least ten Mac users who have said that they keep a Winblows box around to "play games."
VirtualPC is handy, but it just plain sucks when it comes to doing high-end graphics (or, better said, just plain doesn't do high-end graphics).
Everyone is saying its endorsing a Microsoft "standard," but if you think about it it could take people off the Windows desktop, which is really our goal anyway.
So Microsoft gets to license a high-speed graphics library. So it sorta endorses the XBox. Who cares... they don't have monopolies in these areas.
First things first... lots of people are saying that ethernet doesn't require a ground. That's WRONG... a ground is always required, especially on transmission lines like ethernet cables. However, CAT5 is a balanced transmission line and shielding isn't all that important unless you're running the cable through an environment likely to disrupt this balance.
Second, the type of boat you're on makes a big difference. If you're on a metal hulled boat (or a boat with a metal mast or other convenient absolute ground), you're ground doesn't float... the water is ground. Salt water is especially good as a ground reference.
If you're in a fiberglass boat, the whole vessel is floating above ground. See if you can find a metal object (preferably brass or other non-oxidizing metal) always submerged and use it as your ship's ground.
Either way, the easy answer is don't worry about grounding the shield.
If you run into problems with data corruption (or want to prevent such problems), you should ground BOTH sides of the shield. On long cable runs (longer than a half-wave at your operating frequency) you should ground only ONE side. The hub-side is the best to ground as it is already the central network point... so making it the central grounding point makes sense as well.
The BEST solution is to use something called telescoping grounds. In a telescoping ground, both ends are grounded, but to different shields. Both shields are independent and isolated from one another and overlap for the length of the cable. This prevents common-mode currents on both components and avoids ground-loops at the same time. Professional audio cables use this technique often.
Another option you may not have considered is wireless. With a wireless network, the only ground that's important is that of the base station (for efficiency's sake). The client devices have their own ground reference and its relationship to the base station isn't important.
At any rate, good luck!
This is going to burn out pretty quickly.
In the PanIP complaint, they demand a trial by jury. I can't imagine any (competent) jury in the United States that would award anything to PanIP for this.
It's almost as if they were awarded a patent for a device that absorbs nasal discharge via a paper wicking system. An ingenious idea, certainly, but an obvious one.
As far as I know, DirecTV doesn't put a lot of error correction into their signals... loss of a block of data just scrambles up your picture.
You're forgetting something, though... a digital signal takes up MUCH less space than an analog one, especially when you're encoding voice or music (MP3 or Vorbis, anyone?). Since the signal is much smaller, you can encode error correction in the remaining bandwidth.
This means that what you're listening to through the speakers isn't a real-time signal... it's delayed slightly because you want an opportunity to not only receive the primary signal but the redundant error-correction stream as well.
If you were to interleave all of this data over a period of 30 seconds, you could conceivably have a drop-out of about that long in the signal and still have full-quality audio playing out the speakers.
Of course, if your signal drop-out exceeds the available correction data, you're right in that you'd get nothing (or something other than static).
Seeing as I'm a "color deficient" individual, I just wanted to point out that the majority of people who suffer from some sort of color vision anomaly have absolutely no difficulty in determining which wire is the red one (or green one, etc).
There has been the rare occasion where I can confuse red and brown or yellow and green wires in my electronics projects, but only when the wires are so tiny magnification is almost a necessity anyway. With magnification, I can pick out the correct color.
I am green-weak, meaning that I see fewer shades of green than the average Joe, but I see saturated colors just fine. It's only undersaturated (too dark or too light... pastel) colors that give me problems.
Oddly, those with green weakness can confuse reds as well... this is because the green sensitive cells in your eye are not so much to see green as to differentiate it from red.
Most Police departments nowadays use the Munsell D-15 test for color vision screening. This is a more "real world" color test and most people with common red/green deficiencies (like me) can pass it. It is only people who simply are completely unable to see a color group (such as red or green) that fail.
The old method, which is to use isochromatic random dot fields (the ones where you must tell the examiner what number or figure you see), is so sensitive some people with completely normal color vision will fail.