Does anyone know of a cheap package for these slow, short range applications. Right now, I'm planning on going with my back-up plan: RJ45 in the grill.
I was thinking of that too, but I was just going to stick the RJ-45 on the back bumper. Little flip-open connector covers specifically designed for vehicle use are readily available for hiding trailer harness wires.
OTOH, your later reply about driving in and having the car pop up onto the home LAN is really cool.
But what about issues of powering it? You're not going to want to leave the computer on all the time because your car battery won't live long (days, probably, and car batteries aren't meant for deep discharge cycles); wake-on-LAN features might work. But, at least if it's wired, you can make your own little custom plug including network connection and a separate power circuit to run the computer.
Is it truly that dangerous, or just unjustified panic?
Well, let's put it this way. I work in the marine radar and electronics field, and I have some experience with radar microwaves (which are high-power, very short bursts) and with TV broadcasting microwave relays.
I don't like using cellphones, because I really don't want anything transmitting with a few milliwatts or more of power too close to my brain. I wouldn't point a speed radar gun at my balls, either. And, while I've got a 12GHz transmitter here that puts out 50kW peak power (7 watts RMS, you figure out how long the duty cycle must be, and no Richard Stallman jokes, either...), I have no fear of being around the transmitter, but I *would* avoid standing within about 20 feet of the radiating antenna.
This is non-ionizing radiation. It's not like nuclear energy, in that it won't cause chemical changes within cells. However, all radio waves, just like light, can heat up materials through which they pass. The heating efficiency depends on the frequency and the material being heated; water likes 2.45GHz, which is why most microwave ovens work at that frequency.
So while there are no great long-term risks yet proven, I'd strongly avoid placing myself in harm's way of at least a nasty RF burn... ouch! But I wouldn't worry about the energy from cellphone towers and stuff nearby. It's probably in the picowatts per cm^2 range, nothing to worry about. Mostly, the uninformed are looking for things about which to become paranoid.
Anyone know how hard it would be to extend this to, say, 6 miles?
Another reply to this suggested increading power, indicating that the limit for amateur use was 1,500 watts.
I'm really not up on the licensing issues, so I can't comment on the legality of using the amateur bands for commercial use, etc. but since it's line of sight as opposed to propagated in all directions, the FCC would have to intercept that line of sight to find you and bust you. Not likely, IMHO, but laws are around for a reason. Well, some of them...
More importantly, you're going to have a very hard time getting Gunn diodes and other stuff above a few watts - like, 1 or 2. And even then, they'll be very expensive, because the more energy you want to dissipate, the more heat you're going to produce, which means more surface area for cooling. Everything that operates at these frequencies *has* to be as small as possible or else it simply won't work. Therefore, high-power microwave equipment is generally quite expensive.
If you can get a license to run in the 2.45GHz range, I do have a cheap 500-700W solution - microwave oven magnetrons. But, realistically, they're such cheap crap and put out such a noisy signal that you wouldn't be allowed to use it for transmission.
The real trick is to increase your ERP - "Effective Radiated Power". That's done primarily by giving yourself better antennas. More directional means more gain, which means longer distances. But, as the transceivers are operated further apart, it means the more precise your antenna aim will have to be.
We're talking about things like 1/2 degree of aim left-right or up-down making the difference between getting a connection and not getting a connection. Where, conceivably, the wind sway of a building that you're mounting an antenna on could actually affect your reliability.
So, the factors are power versus cost, antenna gain versus off-axis sensitivity. If you need to go really long distances, you're probably better off building a repeater system somewhere in the middle.
How would this be even as secure as wireless phones? (And we've all got some idea of how secure those can be.) At least with fiber or wire you need proximity...
Sure. But you really won't need to get into things like IP encryption or scrambling the signal at an analog level.
The limitation of using microwaves turns into a terrific advantage: line of sight is required.
I mean, this thing is almost as much of a line-of-sight system as pointing a laser pointer at the side of a building. The path has to be clear, and the two transceivers will have to be pointed at each other.
It depends on the antennas, but to get any range with the power levels discussed, you're going to need something with a fairly good reflector, preferably parabolic. (Hacking a DirecTV antenna comes immediately to mind.) These are incredibly directional; being off by a degree could lose 3dB of signal strength (half your signal) or more.
This means that someone who wishes to intercept your communications has to be directly in line of sight with your existing equipment. If he's behind one antenna or the other, he'll only be able to receive packets from the more distant antenna, since the closer antenna will be transmitting away from him.
Placing anything in the line of sight - let's say a reflector going to a receive-only rig - will attentuate the signal available for communications to a point where your users will notice it.
In fact, I used to work, on a freelance basis, for a TV station in Ottawa. CJOH-TV is located at Clyde and Merivale, and has a microwave uplink to their transmitter at Camp Fortune, Quebec.
One year, the technicians went out on strike, and it was starting to get pretty nasty.
You know those little plastic-foil balloons? Someone from the NABET union went out and bought thousands of these, along with enough helium to fill them. Somehow, the station management found out and immediately gave in to the demands of the union.
It is speculated, and is the subject of great water cooler and craft services table lore in Ottawa's TV community, that the plan was to inflate the balloons and tether them with strings from some location where they'd be blocking the microwave link. Foil balloons would very nicely have scattered CJOH's uplink and taken the station off the air.
That's to illustrate how much line-of-sight issues will be relevant. Line-of-sight usually implies height (to get above trees and buildings and things), which usually makes things pretty difficult to intercept. In CJOH's case, their uplink was only about 30-50 feet above ground level, and would have been fairly easy to stop with balloons but not practical to eavesdrop (not that you'd want to eavesdrop the microwave when you could just have tuned your TV set to channel 13). Eavesdropping this would have required being in the line of sight and actually placing a receiver high enough to be in the beam - which would have to be a fairly permanent installation, you couldn't do it with a balloon or a kite because it would sway too much to keep the antenna aimed.
Now, that's not to say that there isn't some risk of reflection from buildings and things that will be scattering the beam a bit. But the scattered signal reflected off objects will be very tough to receive with any degree of reliability.
I think the point is, if someone really wants to intercept your communications, they will. Take reasonable precautions to prevent it. How reasonable the precautions are will therefore be dictated by how sensitive the information is. I'd suggest that the difficulty in piecing together such a system, as well as the line-of-sight issues involved, will probably be sufficient security for even fairly sensitive data.
Could this be used to communicate with a boat cruising around a lake with the base from home? A two mile radius isn't the world, but it would be fine for an afternoon cruise.
Only if the water was very calm, the ship wasn't vibrating much, and the antennas were being kept in line with each other by tracking systems.
It's really amazing just how directional radio waves become as you get into the microwave range. The best analogy would be light: imagine, x miles apart, trying to point two searchlights at each other and keep them properly aimed.
Now, if you mount one of them on a moving target, both of them have to be able to track each other. Very expensive to buy, very time-consuming to build or troubleshoot.
If you want comms to a boat, use lower-frequency RF. The problems you'll have there - ie. availability of frequencies to use, lower bandwidth, etc. will be easier to overcome than the directional properties of microwaves.
There is a reason he didn't put up his email address.
Of course. I wouldn't put my main e-mail address on a webpage like that, much the same way I don't put my main e-mail address up on Slashdot. Web-based e-mail is wonderfully anonymous (when you kill all browser cookies), and since you only end up downloading the message from the server if you click to open it, you don't waste an hour waiting for a day's worth of spam to be fed down the pipe from your POP3/SMTP mail server. That was probably the easiest option available to him.
Given that the subject matter was illegal and it's not impossible for Hotmail or Yahoo or others to trace IP addresses, my next tactic would be to use an cyber cafe or some other similar place to create the e-mail address. Probably, I'd upload the webpage to the server from another cyber cafe to assure greater anonymity, just in case they're logging IP addresses, too.
Further, it's easy enough to write a Javascript that breaks your e-mail address into two pieces so that webspiders don't find it and spam it, and yet when a user clicks on the link, it gives you the correct and complete address. I'd pass you the script you can add to your own websites to do this but I don't have it handy right now. It's common enough knowledge, I didn't write it.
Subj: Your an idiot. (Score:0)
Hmmm. Generally, if you wish to insult someone effectively, it's better to have a thorough and proper command of the language you are using.
Pursuant to the above paragraph, you will note this convention, used every day in common English:
"your" = possessive. ie. "It's your brain that doesn't work."
"you're" = contraction of "you are". ie. "You are about as intelligent as a tsetse fly."
To combine the two into an impressive demonstration of your new-found (though, ironically, remedial) English skills, you could use a sentence like the following:
"It's not your fault that you're not very intelligent."
Along those same lines, you should be aware of tricky words like "there", "they're" and "their". And "its" vs. "it's" never ceases to confound.
Since I suspect English is your first language, I would expect you to demonstrate a more thorough command of the language than was demonstrated in your post. One's second and third languages are generally expected to display grammatical and contextual errors; but I would doubt you have either the tenacity or the requisite breeding required to learn a second language. I have nothing but respect for those who learn several languages, since it's not an easy process. (I know, I speak several fluently.)
I hope that you get to use this tidbit of information to avoid being marked down on your high school freshman English tests.
Now, isn't there a nice and warm Sony Playstation waiting somewhere for you? Or maybe you prefer a little Jerry Springer?
Yup, 'round about now, Sola, APC and all the others must be having a massive run on Nasdaq.
Better make sure the the batteries in your own UPSes are good...
[BigBlockMopar decides to actually turn off his computers tonight, for the first time in a while.]
Thanks for the best laugh I've had in a long time.
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Taking On A Spammer
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· Score: 1
Yeah, these losers have been filling my mailbox up with crud, too.
I was looking forward to e-mailing the creator of this website to congratulate him for his wonderful efforts, but when I pointed the mouse over the e-mail link, I noticed I'd be e-mailing myself. D'Oh!
Oh man, I don't think I've ever laughed so hard while being so angry. It's the weirdest combination of emotions.
I can't get over what illiterate schlump she is, especially from her screen shots. (I guess Windows' poor security is a good thing after all...)
Dude, I know you're out there, and I'm sure you probably read Slashdot at least occasionally. Thank you for taking the risk to stand up for what is right... even if it's technically illegal.
I suggest that we set up a legal defence fund for this guy, just in case he ever gets caught. How's a little Slashdot charity sound? If we combine our resources, I'm sure he could hire OJ's lawyers - and if they could get OJ off, they can get anyone off.
"-f Flood ping. Outputs packets as fast as they come back or one hundred times per second, whichever is more.
Wow. That's lovely! I can't wait to try it across my home LAN.
This is cool to run on a local LAN. It's interesting to see how many packets can be dropped! Just kindly refrain from running it outside your local net!
Yeah, I value my freedom and the lack of court orders telling me not to use computers. It'll be tempting to try it on the Internet, just like it's tempting to drive as fast as my vehicle will go (6.6L (400CID) V8-powered 1976 Dodge Ram). But for the simpler joys of being able to pursue life and liberty, I'll avoid doing it except under controlled and legal conditions.
[BigBlockMopar is sitting beside his Linux box at the moment and starts reading the MAN pages with a renewed interest.]
I have a friend who read the book and recommended it to me. Both he and I are physics majors; I don't think he minded the math!
Good. So maybe I can ask you a question, and while it's fully probable that you won't know the answers, you'll at least know where to find them and how to distill the technical aspects to a level that we Slashdorks can understand.:)
Gravity -jump and find out; currently scientists are looking for gravity waves, using a VERY large (2+ mile) interferometer with lasers to measure the wave) However, Gravity remains elusive. General Reletivity is gravity, so the combination of the two (possible with string theory) is what excites physicists who are looking for GUT.
I think I share the same fascination with the fundamental forces of nature as the rest of us here; in fact, I had done an internship at a nuclear research facility during my younger days. But, while I have a good instinctive and practical knowledge, I have no hope whatsoever of understanding the theoretical math, so I ask that you go gently with me. I also understand, like I indicated above, that this is not your physics specialty.
In a nutshell, Cole's Notes edition, how does gravity work, according to science's current understanding?
I mean, so far as I can tell, we have a pretty reasonable understanding, at least of how to harness, the other three of the fundamental forces.
We are capable of creating and breaking nuclear bonds, both in (un)controlled fission and uncontrolled fusion. We're pretty capable of transmuting elements from one to another; U-238 into Am-241 for smoke detectors, etc., even if these transmuted elements are just by-products of other processes. Is it gravity or is it gluons that hold together the protons in a nucleus despite their repellant similar charges? (Especially fascinating in some isotopes of helium and lithium that lack neutrons.) Even if we don't know, we have some control over the makeup of an atom.
We're pretty capable of controlling electricity and magnetism; this forum wouldn't be available for me to ask this question if it weren't.
Weak Nuclear -primarily responcible for radiation. I am not to sure what else Weak Nuclear does -(someone wish to elaborate?)
I'm not sure what this means, either. Fission and fusion relate to changes to the makeup of the nucleus; the net number of protons in the nucleus will change the number of electrons required to achieve equilibrium and therefore will affect the chemical properties of the element. Is it possible that weak nuclear refers to chemical properties brought on by the number of electrons required for equilibrium and therefore determines which other elements will chemically react with this element? Or is weak nuclear referring to things like photon emissions as electrons drop shells?
The emissions of radiation I see as being caused by the stronger nuclear forces. As the nucleus gets larger (and gets seeded with neutrons in the right ratios), it becomes more unstable, more likely to break the ?gravity? or ?gluonic? bonds that attach the similarily-charged protons which indirectly control the chemical properties. Net effect: fission occurs, energy is released. Alpha particles are just positive helium ions, beta particles are just electrons (that get shot from the positive nucleus, go figure) and gamma rays are photons of energy released as an infinitesimally small quantity of matter in the nucleus is converted to energy. So, since nuclear radiation is occuring very much as a factor of the strong bonds that hold a nucleus together, is radiation really a part of the weaker nuclear bonds? I must be missing something; I fail to understand.
So, finally, we come to gravity. And, even so, to what I must imagine to be a fairly close relative, magnetism.
We can view magnetic lines of force, it's safe to say that with the right technology, we'll probably be able to do it with gravity, too. But I have a problem conceptualizing the way this can overcome inertia.
It's all well and good to say that we can see the lines of force, but what are the lines of force? What are these invisible strings that pass, without sensation, through my hand and down to the center of the earth as they hold the quarter that is resting in my palm?
Obviously, they're a form of energy, since the application of these forces can overcome inertia.
If I place a screw on my desk and suspend a magnet above it, the screw will remain planted on the desk by gravity until the force of the magnetic field is increased to the point of overcoming gravity.
As the magnet approaches the screw, if I measure the weight of the magnet, it will appear to increase as more of the screw's weight is shifted from the desk to the suspended magnet. Note, of course, that the magnet's mass has not changed.
Once the threshold has been exceeded, the mass of the screw will be entirely supported by the magnetic field and it will overcome inertia to jump free of gravity and stick to the magnet.
Now, that's kinetic energy, caused by the magnetic field. Where is that energy coming from? Is it there because of the energy required to place the screw near the magnet? Or is it coming from inside the magnet, suggesting that magnetic force - and probably gravity, since they're quite probably very closely related - is actually coming from within the atoms of magnetized ferrous metals?
Now, magnetism is a lot more clear in this respect than gravity. If I hold the screw and drop it to the ground, I'm just releasing the potential energy that I incurred as I picked it up off the ground. But I would suggest that the same thing holds true as NASA used gravity to slingshot Voyageur out to past Jupiter - Voyageur has never accumulated potential energy by being removed from the surface of Mars or Jupiter, and yet it's still able to acquire kinetic energy from them.
If this were the case, since you don't get something for nothing, isn't it possible that there's some decay of matter occuring, which might be quantified by Einstein's famous E=mc^2? This would suggest that magnets, and possibly all matter, since all matter is a source of gravity, is "decaying" constantly and spontaneously into energy. Granted, given the numbers involved and the quantities of kinetic energy released, very slowly. But does this mean that all matter (magnetized ferrous products in particular, since they're affected by both forces) is gradually losing mass?
Or am I way off?
Finally, if the magnetic energy, as I suggested, exists and can be turned on and off (aligning domains within ferrous materials by rubbing them with a magnet - or by countering that in a number of ways), is it not somehow possible that one day, we can control gravity, turning it on and off with the same relative ease?
(That's a little hope for the future. I mean, I think we'd *all* like to be able to levitate. It'd be a great party trick.)
What's next, are people going to rant because a company advertises more than another company because it has more money? You people are ridiculous, go ahead, moderate it into oblivion, I HAVE PLENTY OF KARMA,
This in a posting that has a been moderated up to three points. You must love the irony.
One of the great perils of brilliance, my friend, is that often we're so wrapped up in our own future innovations that we miss the value of our current innovations.
The world is our oyster. Let's focus our attention on neutralizing Microsoft. (Let's start by neutering Bill Gates.)
[BigBlockMopar raises a toast to a fellow genius]
:) Yeah, it's off-topic. I, too, have plenty of karma.
Okay. Get these or build them yourself, the knowledge of how to do them is public domain:
Small gasoline engine.
Spur gear to fit crankshaft of small gasoline engine.
Handles. Mount as convenient.
Steel sheet, maybe 1/4" thick, cut into outline of chainsaw blade. Mount engine to steel sheet using small machine screws and bolts. (Don't forget lockwashers!)
Chainsaw chain. Basically, bicycle chain with an attitude. Mount it around the outline of the steel sheet; cut and splice the chain so that there is less than a 1/8" slack for every foot of chain in the loop as you pass it around the spur gear on the engine. Double-check to make sure that the chain isn't loose (which could result in nasty bugs, including possible interruption of other system processes (like eating, breathing, beating of heart, etc.)).
Congratulations! Open-source chainsaw. Modify basic design as you will. Feel free to improve on this design.
(This open source chainsaw covered under the terms and provisions of the GNU Public License.)
Natural Capitalism is a very dangerous idea.
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Natural Capitalism
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· Score: 1
This morning, on my way into the office, I spotted an inchworm walking on the front fender of my truck. Ya know, inchworms are so cute, the way they arch their backs up as they walk. While my truck only gets 7 miles per gallon and I drive it 40 miles every day where a boring car like a Honda would suffice, I consider myself to be an environmentalist for saving that poor little inchworm.
I placed him onto a leaf on a really annoying tree that I've been meaning to cut down for some time now. He's happy, and I get to give myself a pat on the back, because I'm a good person.
[sigh]
Anyone else see the many problems with the above?
The summary of this book, as I read it, had a lot of good ideas, as well as a lot of dangerous ones. For example, the carpet service (as opposed to carpet ownership) would represent, truly enough, a great way to ensure the quality and recyclability of a product.
But it's also pretty short-sighted. Commerce and human nature being what they are, dictates that the carpet service won't want to clean my frequent coffee spills. They won't want to vacuum up the toner that Ester has now spilled for the fourth time. The cost of upkeep to even the best carpet that money can buy - and that we'll be able to make in the foreseeable future - is just way too prohibitive. Scotchguard is a good first step, but it's not everything.
And you know that, as you come to get used to the carpet service and begin to recognize that the carpet isn't yours, aren't you less likely to take care of it?
Which means that the carpet will age faster and have to be replaced sooner. For the carpet service to continue to be profitable, no matter how wonderfully environmentally friendly the carpet may be, it will have to be replaced more frequently - incurring at least the environmental cost of the energy required to make the raw materials into a carpet, let alone transportation and installation energy.
Nope, this tactic is short-sighed and, in my opinion, somewhat more dangerous than the existing (imperfect) system.
I wish all products were built to last forever. I wish they were all easy to upgrade. I wish that they were all built of things that were easily recyclable. But that's not going to happen. I drive my 7 MPG Dodge Ram because it's a 1976 model, it's in great shape, it's built like a tank and it would take a lot to kill it. Even though it's a gas pig, it consumes a lot less energy than crushing it into a little cube and melting it down to make new Toyotas would cost. And, while the Dodge is almost entirely iron and steel so it would be easy to efficiently recycle, continuing to use it as an elderly Dodge pickup truck is infinitely less wasteful than the by-products you'd create if you went to make a couple of Echos with it. Instead, I'm doing my part by building - using re-used parts - a smaller, more efficient engine that will push my truck into the 25 MPG range. I do this because I like doing it; unfortunately, economics dictate that it would be cheaper and easier for me to purchase a new vehicle. And this is the route most people will take.
Do I think we should legislate changes? Nope. I mean, do you really want the government more involved in your life? Aren't governments - all of them - the reigning kings of waste and inefficiency? They're a necessary evil, but let's not give them more to do.
Do I feel bad about being so benign in driving a vehicle that gets 7 MPG? Nope. The petroleum and other natural resources we have are there and would be used by some natural process or another. Sooner or later all petroleum on earth would be burned somehow or another. Tree-huggers should be grateful that it's being burned in such near stoichiometric mecca as it is in a modern car engine.
Plain-old short-sighted capitalism has pushed gas-mileage ratings of today's vehicles up. And that was the work of OPEC oil shortages and other market forces, not the impact of Corporate Average Fuel Economy (CAFE) laws imposed on automakers.
In other words, the system is imperfect, but it works. Natural Capitalism, while very different from Socialism and Communism, relies on a fundamental miscalculation that has been the undoing of Marxist Utopia. Human nature is lazy. Human nature is greedy. Human nature wants something for nothing, and a quick fix at that.
Which is why I feel compelled to lump Natural Capitalism into the same boat as Communism and Socialism: they're great ideas, but don't have a hope in hell of ever working.
Finally, a quote from John Lennon:
Imagine no possessions I wonder if you can...
Re:Gnutella security not related to closed source.
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Gnutella VBS Worm
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· Score: 1
Until gnutella opens its source, it will never be secure. They might be able to fake it, and claim security, but backdoors like this will always exist until there is a large team of dedicated users who can fix bugs and patch code.
Nah, you're missing the point.
First off, forgive my ignorance here, but I had thought that Gnutella was open source?
Regardless, the true power of Gnutella is based on two factors. First and most important being the lack of a centralized server system for the RIAA/MPAA/etc to shutdown.
But secondly, since it's not restricted to any file type, security of the executeables downloaded is a user issue. Do you want Gnutella to ban VBS files? That would just hurt people wanting to transfer legitimate VBS scripts.
In fact, Napster could be used to transfer this stuff. Just Wrapsterize it, give it an interesting title, and away it goes.
How about banning executeables?
Again, that just hobbles the usefulness of the system and limits the user base.
Unlike the constant Outlook fiascos, the only way to transfer this worm is to actually decide to download it from another user and then execute it, versus the Outlook model where it just appears in a user's mailbox. If you practise safe surfing, it's not an issue.
umm... putting it into the background (so you can ping almost instantaneously again). since your average ping takes 5 seconds, a loop that pings every 5 seconds isn't exactly very useful.
Oops. Yeah. Don't flame me, I've been playing with Linux in a concerted way for only a couple of weeks now (and the entire last week has been spent trying to get DHCPCD to work).
When you explained it to me, I remembered reading about the ampersand, but since I haven't used it yet, it's still not firmly in my mind.:)
Now, a question, entirely for academic reasons, because I don't plan on doing this. Won't pinging using the ampersand eventually crash the computer?
My thought process is this: You ping, and put the process into the background. You then loop back and ping again, putting that into the background. Since you're going to be looping faster than the ping completes, the number of processes will grow very quickly.
I assume memory will be the limiting factor in the number of allowable processes, or CPU cycles will become so scarce that timing-dependant hardware support will start to fail? And how will the computer stop as it approaches that limit?
(I'd fire it up and try it out against a Windows box on my home LAN, but my Linux box is at the office at the moment.)
or heck, do this: loop: ping -f slashdot.org & goto loop. this'll screw everything up. heh.
For the same reason that I can't try the above on my home LAN, I'm also unable to see the man page for ping... what's the f switch for?
Jeez. Learning Linux is being great for reminding me why I shouldn't take my computer skills for granted.
Re:Trolls 'n Flames, Flamers and Ho's
on
Iridium Saved?
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· Score: 1
Also, you really should do a little S'mores research. Yummy!
Hey man, I've got a bag of marshmallows, a Hershey bar and a Zippo lighter beside my computer at all times.
(Must stop using alligator clip on anti-stat mat to hold marshmallows. Must stop...)
Re: Roll Your Own Geosyncronous Comms Satellites
on
Iridium Saved?
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· Score: 1
Who said we were planning on launching this commercially?
Nothing. But while it'd be really cool to have a satellite orbiting the earth just for your amusement and ego-trip, it's not gonna happen unless you're Bill Gates. (I doubt Trump could afford to pull it off, for sake of cost analogy.)
I'm sure The Donald would love to have a big orbiting "T".
The great thing about this launch cost is that it makes organizations think more before they put something into orbit. And this cuts down on space debris, which is a growing hazard.
To maintain something in orbit, it has to be travelling at several thousand miles per hour. I forget what the exact bottom-end figure was, but it's very amazingly high. Since this is in (effectively) a vacuum, there's no friction to slow the orbiting object down, and therefore they can remain aloft for years before slowing to the point of impact. Consider the moon: it's a satellite, it orbits earth. If it weren't moving so damned fast (we see it as lunar cycles from earth), it wouldn't have the centrifugal force required to balance the pull of earth's gravity, and it would crash into us.
As a satellite encounters trace gases in space, the friction from contact with those trace gases will eventually slow it down to the point of getting pulled into the atmosphere and burning up. (Although SkyLab didn't completely burn up...)
Now, why is debris such a risk? Even worse than the small chances of the thing coming back and big chunks of hot metal raining down on a city, you have to consider what happens when one object impacts another one.
When you hit a telephone pole with a car, the force of impact is a function of the mass of the vehicle and its speed. A 4,000lb car at 100MPH will do a lot of damage to the telephone pole. (*What* telephone pole? All I see is a pile of toothpicks!)
Now, when a 40lb chunk of metal that fell off your homebrew satellite is orbiting at 10,000MPH and happens to hit the side of the newly-comleted International Space Station sometime in the future, you tell me what happens.
Putting protective shielding into everything up there would be nice, but it's really very expensive to do because of the costs in fuel and rocket size per pound of launch weight. And the bigger the rocket, the bigger the booster tanks, which means the bigger the explosion and the more scattered the orbiting debris will be when an O-ring pops a la Challenger.
So, to conclude this thesis, ain't no way you're gonna do it, and for the safety of space exploration and research, it's a damned good thing that every yahoo out there can't launch one off the back of his pickup truck.
Or for that matter, using commercial parts?
Well, you could start collecting your fertilizer and ammonia now, but I think the FBI will get concerned about another Oklahoma City incident and will stop you before you could accumulate enough to get the Zippo that you're planning on using to ignite your engine into orbit.
"But, Your Honor, I didn't know that drinking those bottles of Colt 45 would cause me to lose control of my station wagon and run over all those preschoolers..."
Outlook users: you have been warned.
Re: Roll Your Own Geosyncronous Comms Satellites
on
Iridium Saved?
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· Score: 1
You should really do a little research before posting here and find out an alternative to your money-grubbing One Microsoft Way capitalistic swine-generated trash-talking hypocritical ways.
Oy vey. Life is short, let's try to have a little fun. Sure, it's off-topic. But isn't a good percentage of the joy of Slashdot just the comradery of intelligent conversation, different points of view and a little friendly hazing from time to time?
In a geological sort of time frame, we'll all be rotting corpses lying in little subterranian boxes. Until then, let's play nicely.
The company 'Infinity' makes those speakers. I've got a full set of Infinity speakers for my surround sound setup at home and in my car (replaced my factory speakers with them).
I'm right now hacking a new set into my 1976 Dodge Ram. It's a little retro, I guess, but it's cool putting new Chysler parts into an old Chrysler truck. Even if Infinity isn't owned by Chrysler, it still has a little Pentastar.
Other good car sound systems: GM's Delco-Bose system, as used in early 1990s Cadillacs. And GM also put a kick-ass little system into every 1984 to 1986 Pontiac Fiero: the speakers were in the headrests. (In '87-'88 Fieros, they were in the pillars.) The Fiero sound system was actually very faithful in reproduction, but if you're the sort of person who thinks that good music is all about lots of bass, they're really not for you. These things produced almost concert-hall stereo imaging and had great, clean, full-range response.
As for home use, I'm some kind of purist. I've got a beautiful set of vintage 1970s Acoustic Research AR-4x speakers hooked up to a nice Sound A-5000 amplifier. It seems like such a travesty to have them hooked up to a $50 sound card for playing MP3s.
What if they make satelite phone modems that attach to your laptop?
With today's technology, it's more likely that you'd have to attach the laptop to the satellite phone since it would be significantly smaller than the phone.
The biggest issue is that sending up to the satellite requires a transmitter, with associated size, power and licensing problems.
I mean, cellular phones don't always work overseas and in planes, where internet access is wanted for not only entertainment on flights,
I think the most entertaining part of trying to use a satellite telephony system on a flight would be trying to figure out a way to power the Sawzall you'd need to use to cut a hole in the fuselage directly over your seat.
I don't know what RF frequency Iridium uses, but if it's in space, for a number of reasons, it has to be pretty high. Much like you can put your subwoofer anywhere but you want to be in line of sight with your tweeters, as RF frequency increases, it becomes more directional. At microwave frequencies (about 1GHz and up), it behaves more like light than like an AM or FM radio signal. And I'm sure Iridium is in the microwave bands somewhere.
This means that you're up against the same sort of problems as you have when you try to set up a satellite dish. Ever tried to set up a DirecTV system? It's not as easy as it looks! Portable satellite communications still require a fairly firm place to put the antenna, and then either precise manual adjustability or a full target tracking system that will adjust to the horizon and inclination angles as your base station moves (as in on a ship).
Ever try to aim a satellite dish through a tree or even a thick cloud cover? It's not going to behave too well through aircraft aluminum.
Finally, I can't confirm this for sure, but I had read somewhere that the Iridium system has bandwidth limitations, which makes sense, since it was built for voice. I'm sure their transmit and receive frequencies would support killer broadband, but if the transponders on the satellites would have to be upgraded to get anything more than a 56k internet connection passing between the transmitter and the receiver, there's just no point. I can do that more reliably myself with a cellphone and a PCMCIA Sportster. Upgrading a satellite would be more expensive than putting a new one up (spacewalks don't come cheap). Which means, effectively, that your network is limited to voice and low-bandwidth traffic. And if you can't sell that service and make a profit, it means the network is basically worthless.
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I was thinking of that too, but I was just going to stick the RJ-45 on the back bumper. Little flip-open connector covers specifically designed for vehicle use are readily available for hiding trailer harness wires.
OTOH, your later reply about driving in and having the car pop up onto the home LAN is really cool.
But what about issues of powering it? You're not going to want to leave the computer on all the time because your car battery won't live long (days, probably, and car batteries aren't meant for deep discharge cycles); wake-on-LAN features might work. But, at least if it's wired, you can make your own little custom plug including network connection and a separate power circuit to run the computer.
Well, let's put it this way. I work in the marine radar and electronics field, and I have some experience with radar microwaves (which are high-power, very short bursts) and with TV broadcasting microwave relays.
I don't like using cellphones, because I really don't want anything transmitting with a few milliwatts or more of power too close to my brain. I wouldn't point a speed radar gun at my balls, either. And, while I've got a 12GHz transmitter here that puts out 50kW peak power (7 watts RMS, you figure out how long the duty cycle must be, and no Richard Stallman jokes, either...), I have no fear of being around the transmitter, but I *would* avoid standing within about 20 feet of the radiating antenna.
This is non-ionizing radiation. It's not like nuclear energy, in that it won't cause chemical changes within cells. However, all radio waves, just like light, can heat up materials through which they pass. The heating efficiency depends on the frequency and the material being heated; water likes 2.45GHz, which is why most microwave ovens work at that frequency.
So while there are no great long-term risks yet proven, I'd strongly avoid placing myself in harm's way of at least a nasty RF burn... ouch! But I wouldn't worry about the energy from cellphone towers and stuff nearby. It's probably in the picowatts per cm^2 range, nothing to worry about. Mostly, the uninformed are looking for things about which to become paranoid.
Another reply to this suggested increading power, indicating that the limit for amateur use was 1,500 watts.
I'm really not up on the licensing issues, so I can't comment on the legality of using the amateur bands for commercial use, etc. but since it's line of sight as opposed to propagated in all directions, the FCC would have to intercept that line of sight to find you and bust you. Not likely, IMHO, but laws are around for a reason. Well, some of them...
More importantly, you're going to have a very hard time getting Gunn diodes and other stuff above a few watts - like, 1 or 2. And even then, they'll be very expensive, because the more energy you want to dissipate, the more heat you're going to produce, which means more surface area for cooling. Everything that operates at these frequencies *has* to be as small as possible or else it simply won't work. Therefore, high-power microwave equipment is generally quite expensive.
If you can get a license to run in the 2.45GHz range, I do have a cheap 500-700W solution - microwave oven magnetrons. But, realistically, they're such cheap crap and put out such a noisy signal that you wouldn't be allowed to use it for transmission.
The real trick is to increase your ERP - "Effective Radiated Power". That's done primarily by giving yourself better antennas. More directional means more gain, which means longer distances. But, as the transceivers are operated further apart, it means the more precise your antenna aim will have to be.
We're talking about things like 1/2 degree of aim left-right or up-down making the difference between getting a connection and not getting a connection. Where, conceivably, the wind sway of a building that you're mounting an antenna on could actually affect your reliability.
So, the factors are power versus cost, antenna gain versus off-axis sensitivity. If you need to go really long distances, you're probably better off building a repeater system somewhere in the middle.
Sure. But you really won't need to get into things like IP encryption or scrambling the signal at an analog level.
The limitation of using microwaves turns into a terrific advantage: line of sight is required.
I mean, this thing is almost as much of a line-of-sight system as pointing a laser pointer at the side of a building. The path has to be clear, and the two transceivers will have to be pointed at each other.
It depends on the antennas, but to get any range with the power levels discussed, you're going to need something with a fairly good reflector, preferably parabolic. (Hacking a DirecTV antenna comes immediately to mind.) These are incredibly directional; being off by a degree could lose 3dB of signal strength (half your signal) or more.
This means that someone who wishes to intercept your communications has to be directly in line of sight with your existing equipment. If he's behind one antenna or the other, he'll only be able to receive packets from the more distant antenna, since the closer antenna will be transmitting away from him.
Placing anything in the line of sight - let's say a reflector going to a receive-only rig - will attentuate the signal available for communications to a point where your users will notice it.
In fact, I used to work, on a freelance basis, for a TV station in Ottawa. CJOH-TV is located at Clyde and Merivale, and has a microwave uplink to their transmitter at Camp Fortune, Quebec.
One year, the technicians went out on strike, and it was starting to get pretty nasty.
You know those little plastic-foil balloons? Someone from the NABET union went out and bought thousands of these, along with enough helium to fill them. Somehow, the station management found out and immediately gave in to the demands of the union.
It is speculated, and is the subject of great water cooler and craft services table lore in Ottawa's TV community, that the plan was to inflate the balloons and tether them with strings from some location where they'd be blocking the microwave link. Foil balloons would very nicely have scattered CJOH's uplink and taken the station off the air.
That's to illustrate how much line-of-sight issues will be relevant. Line-of-sight usually implies height (to get above trees and buildings and things), which usually makes things pretty difficult to intercept. In CJOH's case, their uplink was only about 30-50 feet above ground level, and would have been fairly easy to stop with balloons but not practical to eavesdrop (not that you'd want to eavesdrop the microwave when you could just have tuned your TV set to channel 13). Eavesdropping this would have required being in the line of sight and actually placing a receiver high enough to be in the beam - which would have to be a fairly permanent installation, you couldn't do it with a balloon or a kite because it would sway too much to keep the antenna aimed.
Now, that's not to say that there isn't some risk of reflection from buildings and things that will be scattering the beam a bit. But the scattered signal reflected off objects will be very tough to receive with any degree of reliability.
I think the point is, if someone really wants to intercept your communications, they will. Take reasonable precautions to prevent it. How reasonable the precautions are will therefore be dictated by how sensitive the information is. I'd suggest that the difficulty in piecing together such a system, as well as the line-of-sight issues involved, will probably be sufficient security for even fairly sensitive data.
Only if the water was very calm, the ship wasn't vibrating much, and the antennas were being kept in line with each other by tracking systems.
It's really amazing just how directional radio waves become as you get into the microwave range. The best analogy would be light: imagine, x miles apart, trying to point two searchlights at each other and keep them properly aimed.
Now, if you mount one of them on a moving target, both of them have to be able to track each other. Very expensive to buy, very time-consuming to build or troubleshoot.
If you want comms to a boat, use lower-frequency RF. The problems you'll have there - ie. availability of frequencies to use, lower bandwidth, etc. will be easier to overcome than the directional properties of microwaves.
but the lead chips taste soooooooooo good!
That they do. I used to lick roof-flashing, myself. But now, I'm more of a mercury-through-skin kind of guy.
Oops. Time for me to break my midnight thermometer... gotta run. ;)
Of course. I wouldn't put my main e-mail address on a webpage like that, much the same way I don't put my main e-mail address up on Slashdot. Web-based e-mail is wonderfully anonymous (when you kill all browser cookies), and since you only end up downloading the message from the server if you click to open it, you don't waste an hour waiting for a day's worth of spam to be fed down the pipe from your POP3/SMTP mail server. That was probably the easiest option available to him.
Given that the subject matter was illegal and it's not impossible for Hotmail or Yahoo or others to trace IP addresses, my next tactic would be to use an cyber cafe or some other similar place to create the e-mail address. Probably, I'd upload the webpage to the server from another cyber cafe to assure greater anonymity, just in case they're logging IP addresses, too.
Further, it's easy enough to write a Javascript that breaks your e-mail address into two pieces so that webspiders don't find it and spam it, and yet when a user clicks on the link, it gives you the correct and complete address. I'd pass you the script you can add to your own websites to do this but I don't have it handy right now. It's common enough knowledge, I didn't write it.
Subj: Your an idiot. (Score:0)Hmmm. Generally, if you wish to insult someone effectively, it's better to have a thorough and proper command of the language you are using.
Pursuant to the above paragraph, you will note this convention, used every day in common English:
"your" = possessive. ie. "It's your brain that doesn't work."
"you're" = contraction of "you are". ie. "You are about as intelligent as a tsetse fly."
To combine the two into an impressive demonstration of your new-found (though, ironically, remedial) English skills, you could use a sentence like the following:
"It's not your fault that you're not very intelligent."
Along those same lines, you should be aware of tricky words like "there", "they're" and "their". And "its" vs. "it's" never ceases to confound.
Since I suspect English is your first language, I would expect you to demonstrate a more thorough command of the language than was demonstrated in your post. One's second and third languages are generally expected to display grammatical and contextual errors; but I would doubt you have either the tenacity or the requisite breeding required to learn a second language. I have nothing but respect for those who learn several languages, since it's not an easy process. (I know, I speak several fluently.)
I hope that you get to use this tidbit of information to avoid being marked down on your high school freshman English tests.
Now, isn't there a nice and warm Sony Playstation waiting somewhere for you? Or maybe you prefer a little Jerry Springer?
Yup, 'round about now, Sola, APC and all the others must be having a massive run on Nasdaq.
Better make sure the the batteries in your own UPSes are good...
[BigBlockMopar decides to actually turn off his computers tonight, for the first time in a while.]
Yeah, these losers have been filling my mailbox up with crud, too.
I was looking forward to e-mailing the creator of this website to congratulate him for his wonderful efforts, but when I pointed the mouse over the e-mail link, I noticed I'd be e-mailing myself. D'Oh!
Oh man, I don't think I've ever laughed so hard while being so angry. It's the weirdest combination of emotions.
I can't get over what illiterate schlump she is, especially from her screen shots. (I guess Windows' poor security is a good thing after all...)
Dude, I know you're out there, and I'm sure you probably read Slashdot at least occasionally. Thank you for taking the risk to stand up for what is right... even if it's technically illegal.
I suggest that we set up a legal defence fund for this guy, just in case he ever gets caught. How's a little Slashdot charity sound? If we combine our resources, I'm sure he could hire OJ's lawyers - and if they could get OJ off, they can get anyone off.
Wow. That's lovely! I can't wait to try it across my home LAN.
This is cool to run on a local LAN. It's interesting to see how many packets can be dropped! Just kindly refrain from running it outside your local net!Yeah, I value my freedom and the lack of court orders telling me not to use computers. It'll be tempting to try it on the Internet, just like it's tempting to drive as fast as my vehicle will go (6.6L (400CID) V8-powered 1976 Dodge Ram). But for the simpler joys of being able to pursue life and liberty, I'll avoid doing it except under controlled and legal conditions.
[BigBlockMopar is sitting beside his Linux box at the moment and starts reading the MAN pages with a renewed interest.]
Thanks!
Good. So maybe I can ask you a question, and while it's fully probable that you won't know the answers, you'll at least know where to find them and how to distill the technical aspects to a level that we Slashdorks can understand. :)
Gravity -jump and find out; currently scientists are looking for gravity waves, using a VERY large (2+ mile) interferometer with lasers to measure the wave)However, Gravity remains elusive. General Reletivity is gravity, so the combination of the two (possible with string theory) is what excites physicists who are looking for GUT.
I think I share the same fascination with the fundamental forces of nature as the rest of us here; in fact, I had done an internship at a nuclear research facility during my younger days. But, while I have a good instinctive and practical knowledge, I have no hope whatsoever of understanding the theoretical math, so I ask that you go gently with me. I also understand, like I indicated above, that this is not your physics specialty.
In a nutshell, Cole's Notes edition, how does gravity work, according to science's current understanding?
I mean, so far as I can tell, we have a pretty reasonable understanding, at least of how to harness, the other three of the fundamental forces.
We are capable of creating and breaking nuclear bonds, both in (un)controlled fission and uncontrolled fusion. We're pretty capable of transmuting elements from one to another; U-238 into Am-241 for smoke detectors, etc., even if these transmuted elements are just by-products of other processes. Is it gravity or is it gluons that hold together the protons in a nucleus despite their repellant similar charges? (Especially fascinating in some isotopes of helium and lithium that lack neutrons.) Even if we don't know, we have some control over the makeup of an atom.
We're pretty capable of controlling electricity and magnetism; this forum wouldn't be available for me to ask this question if it weren't.
Weak Nuclear -primarily responcible for radiation. I am not to sure what else Weak Nuclear does -(someone wish to elaborate?)I'm not sure what this means, either. Fission and fusion relate to changes to the makeup of the nucleus; the net number of protons in the nucleus will change the number of electrons required to achieve equilibrium and therefore will affect the chemical properties of the element. Is it possible that weak nuclear refers to chemical properties brought on by the number of electrons required for equilibrium and therefore determines which other elements will chemically react with this element? Or is weak nuclear referring to things like photon emissions as electrons drop shells?
The emissions of radiation I see as being caused by the stronger nuclear forces. As the nucleus gets larger (and gets seeded with neutrons in the right ratios), it becomes more unstable, more likely to break the ?gravity? or ?gluonic? bonds that attach the similarily-charged protons which indirectly control the chemical properties. Net effect: fission occurs, energy is released. Alpha particles are just positive helium ions, beta particles are just electrons (that get shot from the positive nucleus, go figure) and gamma rays are photons of energy released as an infinitesimally small quantity of matter in the nucleus is converted to energy. So, since nuclear radiation is occuring very much as a factor of the strong bonds that hold a nucleus together, is radiation really a part of the weaker nuclear bonds? I must be missing something; I fail to understand.
So, finally, we come to gravity. And, even so, to what I must imagine to be a fairly close relative, magnetism.
We can view magnetic lines of force, it's safe to say that with the right technology, we'll probably be able to do it with gravity, too. But I have a problem conceptualizing the way this can overcome inertia.
It's all well and good to say that we can see the lines of force, but what are the lines of force? What are these invisible strings that pass, without sensation, through my hand and down to the center of the earth as they hold the quarter that is resting in my palm?
Obviously, they're a form of energy, since the application of these forces can overcome inertia.
If I place a screw on my desk and suspend a magnet above it, the screw will remain planted on the desk by gravity until the force of the magnetic field is increased to the point of overcoming gravity.
As the magnet approaches the screw, if I measure the weight of the magnet, it will appear to increase as more of the screw's weight is shifted from the desk to the suspended magnet. Note, of course, that the magnet's mass has not changed.
Once the threshold has been exceeded, the mass of the screw will be entirely supported by the magnetic field and it will overcome inertia to jump free of gravity and stick to the magnet.
Now, that's kinetic energy, caused by the magnetic field. Where is that energy coming from? Is it there because of the energy required to place the screw near the magnet? Or is it coming from inside the magnet, suggesting that magnetic force - and probably gravity, since they're quite probably very closely related - is actually coming from within the atoms of magnetized ferrous metals?
Now, magnetism is a lot more clear in this respect than gravity. If I hold the screw and drop it to the ground, I'm just releasing the potential energy that I incurred as I picked it up off the ground. But I would suggest that the same thing holds true as NASA used gravity to slingshot Voyageur out to past Jupiter - Voyageur has never accumulated potential energy by being removed from the surface of Mars or Jupiter, and yet it's still able to acquire kinetic energy from them.
If this were the case, since you don't get something for nothing, isn't it possible that there's some decay of matter occuring, which might be quantified by Einstein's famous E=mc^2? This would suggest that magnets, and possibly all matter, since all matter is a source of gravity, is "decaying" constantly and spontaneously into energy. Granted, given the numbers involved and the quantities of kinetic energy released, very slowly. But does this mean that all matter (magnetized ferrous products in particular, since they're affected by both forces) is gradually losing mass?
Or am I way off?
Finally, if the magnetic energy, as I suggested, exists and can be turned on and off (aligning domains within ferrous materials by rubbing them with a magnet - or by countering that in a number of ways), is it not somehow possible that one day, we can control gravity, turning it on and off with the same relative ease?
(That's a little hope for the future. I mean, I think we'd *all* like to be able to levitate. It'd be a great party trick.)
And, to add a grisly twist, in the time it took me to post the reply from which this is excerpted, a moderator has scored the posting down by one.
Must be an excite@home employee.
You people are ridiculous, go ahead, moderate it into oblivion, I HAVE PLENTY OF KARMA,
This in a posting that has a been moderated up to three points. You must love the irony.
One of the great perils of brilliance, my friend, is that often we're so wrapped up in our own future innovations that we miss the value of our current innovations.
The world is our oyster. Let's focus our attention on neutralizing Microsoft. (Let's start by neutering Bill Gates.)
[BigBlockMopar raises a toast to a fellow genius]
:) Yeah, it's off-topic. I, too, have plenty of karma.
Okay. Get these or build them yourself, the knowledge of how to do them is public domain:
Small gasoline engine.
Spur gear to fit crankshaft of small gasoline engine.
Handles. Mount as convenient.
Steel sheet, maybe 1/4" thick, cut into outline of chainsaw blade. Mount engine to steel sheet using small machine screws and bolts. (Don't forget lockwashers!)
Chainsaw chain. Basically, bicycle chain with an attitude. Mount it around the outline of the steel sheet; cut and splice the chain so that there is less than a 1/8" slack for every foot of chain in the loop as you pass it around the spur gear on the engine. Double-check to make sure that the chain isn't loose (which could result in nasty bugs, including possible interruption of other system processes (like eating, breathing, beating of heart, etc.)).
Congratulations! Open-source chainsaw. Modify basic design as you will. Feel free to improve on this design.
(This open source chainsaw covered under the terms and provisions of the GNU Public License.)
This morning, on my way into the office, I spotted an inchworm walking on the front fender of my truck. Ya know, inchworms are so cute, the way they arch their backs up as they walk. While my truck only gets 7 miles per gallon and I drive it 40 miles every day where a boring car like a Honda would suffice, I consider myself to be an environmentalist for saving that poor little inchworm.
I placed him onto a leaf on a really annoying tree that I've been meaning to cut down for some time now. He's happy, and I get to give myself a pat on the back, because I'm a good person.
[sigh]
Anyone else see the many problems with the above?
The summary of this book, as I read it, had a lot of good ideas, as well as a lot of dangerous ones. For example, the carpet service (as opposed to carpet ownership) would represent, truly enough, a great way to ensure the quality and recyclability of a product.
But it's also pretty short-sighted. Commerce and human nature being what they are, dictates that the carpet service won't want to clean my frequent coffee spills. They won't want to vacuum up the toner that Ester has now spilled for the fourth time. The cost of upkeep to even the best carpet that money can buy - and that we'll be able to make in the foreseeable future - is just way too prohibitive. Scotchguard is a good first step, but it's not everything.
And you know that, as you come to get used to the carpet service and begin to recognize that the carpet isn't yours, aren't you less likely to take care of it?
Which means that the carpet will age faster and have to be replaced sooner. For the carpet service to continue to be profitable, no matter how wonderfully environmentally friendly the carpet may be, it will have to be replaced more frequently - incurring at least the environmental cost of the energy required to make the raw materials into a carpet, let alone transportation and installation energy.
Nope, this tactic is short-sighed and, in my opinion, somewhat more dangerous than the existing (imperfect) system.
I wish all products were built to last forever. I wish they were all easy to upgrade. I wish that they were all built of things that were easily recyclable. But that's not going to happen. I drive my 7 MPG Dodge Ram because it's a 1976 model, it's in great shape, it's built like a tank and it would take a lot to kill it. Even though it's a gas pig, it consumes a lot less energy than crushing it into a little cube and melting it down to make new Toyotas would cost. And, while the Dodge is almost entirely iron and steel so it would be easy to efficiently recycle, continuing to use it as an elderly Dodge pickup truck is infinitely less wasteful than the by-products you'd create if you went to make a couple of Echos with it. Instead, I'm doing my part by building - using re-used parts - a smaller, more efficient engine that will push my truck into the 25 MPG range. I do this because I like doing it; unfortunately, economics dictate that it would be cheaper and easier for me to purchase a new vehicle. And this is the route most people will take.
Do I think we should legislate changes? Nope. I mean, do you really want the government more involved in your life? Aren't governments - all of them - the reigning kings of waste and inefficiency? They're a necessary evil, but let's not give them more to do.
Do I feel bad about being so benign in driving a vehicle that gets 7 MPG? Nope. The petroleum and other natural resources we have are there and would be used by some natural process or another. Sooner or later all petroleum on earth would be burned somehow or another. Tree-huggers should be grateful that it's being burned in such near stoichiometric mecca as it is in a modern car engine.
Plain-old short-sighted capitalism has pushed gas-mileage ratings of today's vehicles up. And that was the work of OPEC oil shortages and other market forces, not the impact of Corporate Average Fuel Economy (CAFE) laws imposed on automakers.
In other words, the system is imperfect, but it works. Natural Capitalism, while very different from Socialism and Communism, relies on a fundamental miscalculation that has been the undoing of Marxist Utopia. Human nature is lazy. Human nature is greedy. Human nature wants something for nothing, and a quick fix at that.
Which is why I feel compelled to lump Natural Capitalism into the same boat as Communism and Socialism: they're great ideas, but don't have a hope in hell of ever working.
Finally, a quote from John Lennon:
Imagine no possessionsI wonder if you can...
Nah, you're missing the point.
First off, forgive my ignorance here, but I had thought that Gnutella was open source?
Regardless, the true power of Gnutella is based on two factors. First and most important being the lack of a centralized server system for the RIAA/MPAA/etc to shutdown.
But secondly, since it's not restricted to any file type, security of the executeables downloaded is a user issue. Do you want Gnutella to ban VBS files? That would just hurt people wanting to transfer legitimate VBS scripts.
In fact, Napster could be used to transfer this stuff. Just Wrapsterize it, give it an interesting title, and away it goes.
How about banning executeables?
Again, that just hobbles the usefulness of the system and limits the user base.
Unlike the constant Outlook fiascos, the only way to transfer this worm is to actually decide to download it from another user and then execute it, versus the Outlook model where it just appears in a user's mailbox. If you practise safe surfing, it's not an issue.
Oops. Yeah. Don't flame me, I've been playing with Linux in a concerted way for only a couple of weeks now (and the entire last week has been spent trying to get DHCPCD to work).
When you explained it to me, I remembered reading about the ampersand, but since I haven't used it yet, it's still not firmly in my mind. :)
Now, a question, entirely for academic reasons, because I don't plan on doing this. Won't pinging using the ampersand eventually crash the computer?
My thought process is this: You ping, and put the process into the background. You then loop back and ping again, putting that into the background. Since you're going to be looping faster than the ping completes, the number of processes will grow very quickly.
I assume memory will be the limiting factor in the number of allowable processes, or CPU cycles will become so scarce that timing-dependant hardware support will start to fail? And how will the computer stop as it approaches that limit?
(I'd fire it up and try it out against a Windows box on my home LAN, but my Linux box is at the office at the moment.)
or heck, do this:loop:
ping -f slashdot.org &
goto loop.
this'll screw everything up. heh.
For the same reason that I can't try the above on my home LAN, I'm also unable to see the man page for ping... what's the f switch for?
Jeez. Learning Linux is being great for reminding me why I shouldn't take my computer skills for granted.
Hey man, I've got a bag of marshmallows, a Hershey bar and a Zippo lighter beside my computer at all times.
(Must stop using alligator clip on anti-stat mat to hold marshmallows. Must stop...)
Nothing. But while it'd be really cool to have a satellite orbiting the earth just for your amusement and ego-trip, it's not gonna happen unless you're Bill Gates. (I doubt Trump could afford to pull it off, for sake of cost analogy.)
I'm sure The Donald would love to have a big orbiting "T".
The great thing about this launch cost is that it makes organizations think more before they put something into orbit. And this cuts down on space debris, which is a growing hazard.
To maintain something in orbit, it has to be travelling at several thousand miles per hour. I forget what the exact bottom-end figure was, but it's very amazingly high. Since this is in (effectively) a vacuum, there's no friction to slow the orbiting object down, and therefore they can remain aloft for years before slowing to the point of impact. Consider the moon: it's a satellite, it orbits earth. If it weren't moving so damned fast (we see it as lunar cycles from earth), it wouldn't have the centrifugal force required to balance the pull of earth's gravity, and it would crash into us.
As a satellite encounters trace gases in space, the friction from contact with those trace gases will eventually slow it down to the point of getting pulled into the atmosphere and burning up. (Although SkyLab didn't completely burn up...)
Now, why is debris such a risk? Even worse than the small chances of the thing coming back and big chunks of hot metal raining down on a city, you have to consider what happens when one object impacts another one.
When you hit a telephone pole with a car, the force of impact is a function of the mass of the vehicle and its speed. A 4,000lb car at 100MPH will do a lot of damage to the telephone pole. (*What* telephone pole? All I see is a pile of toothpicks!)
Now, when a 40lb chunk of metal that fell off your homebrew satellite is orbiting at 10,000MPH and happens to hit the side of the newly-comleted International Space Station sometime in the future, you tell me what happens.
Putting protective shielding into everything up there would be nice, but it's really very expensive to do because of the costs in fuel and rocket size per pound of launch weight. And the bigger the rocket, the bigger the booster tanks, which means the bigger the explosion and the more scattered the orbiting debris will be when an O-ring pops a la Challenger.
So, to conclude this thesis, ain't no way you're gonna do it, and for the safety of space exploration and research, it's a damned good thing that every yahoo out there can't launch one off the back of his pickup truck.
Or for that matter, using commercial parts?Well, you could start collecting your fertilizer and ammonia now, but I think the FBI will get concerned about another Oklahoma City incident and will stop you before you could accumulate enough to get the Zippo that you're planning on using to ignite your engine into orbit.
A parallel:
"But, Your Honor, I didn't know that drinking those bottles of Colt 45 would cause me to lose control of my station wagon and run over all those preschoolers..."
Outlook users: you have been warned.
Oy vey. Life is short, let's try to have a little fun. Sure, it's off-topic. But isn't a good percentage of the joy of Slashdot just the comradery of intelligent conversation, different points of view and a little friendly hazing from time to time?
In a geological sort of time frame, we'll all be rotting corpses lying in little subterranian boxes. Until then, let's play nicely.
I'm right now hacking a new set into my 1976 Dodge Ram. It's a little retro, I guess, but it's cool putting new Chysler parts into an old Chrysler truck. Even if Infinity isn't owned by Chrysler, it still has a little Pentastar.
Other good car sound systems: GM's Delco-Bose system, as used in early 1990s Cadillacs. And GM also put a kick-ass little system into every 1984 to 1986 Pontiac Fiero: the speakers were in the headrests. (In '87-'88 Fieros, they were in the pillars.) The Fiero sound system was actually very faithful in reproduction, but if you're the sort of person who thinks that good music is all about lots of bass, they're really not for you. These things produced almost concert-hall stereo imaging and had great, clean, full-range response.
As for home use, I'm some kind of purist. I've got a beautiful set of vintage 1970s Acoustic Research AR-4x speakers hooked up to a nice Sound A-5000 amplifier. It seems like such a travesty to have them hooked up to a $50 sound card for playing MP3s.
With today's technology, it's more likely that you'd have to attach the laptop to the satellite phone since it would be significantly smaller than the phone.
The biggest issue is that sending up to the satellite requires a transmitter, with associated size, power and licensing problems.
I mean, cellular phones don't always work overseas and in planes, where internet access is wanted for not only entertainment on flights,I think the most entertaining part of trying to use a satellite telephony system on a flight would be trying to figure out a way to power the Sawzall you'd need to use to cut a hole in the fuselage directly over your seat.
I don't know what RF frequency Iridium uses, but if it's in space, for a number of reasons, it has to be pretty high. Much like you can put your subwoofer anywhere but you want to be in line of sight with your tweeters, as RF frequency increases, it becomes more directional. At microwave frequencies (about 1GHz and up), it behaves more like light than like an AM or FM radio signal. And I'm sure Iridium is in the microwave bands somewhere.
This means that you're up against the same sort of problems as you have when you try to set up a satellite dish. Ever tried to set up a DirecTV system? It's not as easy as it looks! Portable satellite communications still require a fairly firm place to put the antenna, and then either precise manual adjustability or a full target tracking system that will adjust to the horizon and inclination angles as your base station moves (as in on a ship).
Ever try to aim a satellite dish through a tree or even a thick cloud cover? It's not going to behave too well through aircraft aluminum.
Finally, I can't confirm this for sure, but I had read somewhere that the Iridium system has bandwidth limitations, which makes sense, since it was built for voice. I'm sure their transmit and receive frequencies would support killer broadband, but if the transponders on the satellites would have to be upgraded to get anything more than a 56k internet connection passing between the transmitter and the receiver, there's just no point. I can do that more reliably myself with a cellphone and a PCMCIA Sportster. Upgrading a satellite would be more expensive than putting a new one up (spacewalks don't come cheap). Which means, effectively, that your network is limited to voice and low-bandwidth traffic. And if you can't sell that service and make a profit, it means the network is basically worthless.
Yay! I can't wait to download 1984 off Gnutella as a form of protest!
ping slashdot.org &
goto loop Okay, I'll bite. What's the ampersand for?
:)