you just don't know, for example, if the dome light circuit is going to happen to be connected to the same bank of circuits that were smushed into the Big Orange Cable in a front-quarter collision that also happened to damage the fail-safe circuit breakers.
That is why you need a high voltage DC-rated fuse, as close to the battery terminal as possible. An electronic breaker is not as safe (it can fail stuck on), and a mechanical circuit breaker for high voltage/high current DC circuits is unbelievably expensive. This fuse is about the size of a beer can, not your ordinary 3AG or ATC fuse for a 12V circuit. There's a case to be made for an external kill switch, too (if they can make it vandal-resistant, but quickly accessible to the rescue squad).
There are political angles to this. To justify the shuttle program, it had to support as many other missions as possible. Other missions were designed with the shuttle in mind, assuming far lower launch costs and more frequent shuttle missions than the shuttle fleet has delivered (as other commenters have pointed out). NASA deliberately steered new missions away from exendable (unmanned) boosters and deemphasized expendable booster programs. Why? Because manned space flight could get congressional support ($$$), but boring science robots don't! Space science never beats space politics; science programs must be allies to the politically powerful. Turning Tom Wolfe's phrase around, no Buck Rogers-no bucks!
The shuttle was a big, expensive, funded hammer, so other programs became its nails as a survival tactic. Hubble could gave been designed differently. But if it had, it likely would have been a budget victim and never flown.
Oh, so they want payola now? There's a bad precedent if there ever was one. Their price list makes the bi-annual software upgrade look cheap by comparison. Even a non-profit has to fork over a $375 application fee. Why should the innocent victims have to pay?
These hopelessly ineffective anti-spam "services" fail to consider the impact of their business methods on the poor users. Every one is different. Every one wants you to do a Special Thing to prove your innocence. Every week someone else decides they have the ultimate solution to spam. They are a collective nuisance, both because of the meta-spam challenges their systems produce and because they needlessly delay mail delivery. And they never worry about what happens when dozens of others are trying to do the same thing in different ways.
If you want to harvest live email addresses, grabbing them from replies to an anti-spam "service" would be a great way to go. If you want to have people foolishly click a link exploiting the latest buffer-overflow vulnerability, an anti-spam "service" message should produce lots of hits.
Attention clueless anti-spam entrepeneurs: I don't know you. I don't trust you. I won't click your handy verify link. And I certainly won't pay you any protection money!
The range wasn't adequate for non-stop trans Pacific routes. On these long distance routes where Mach 2 speed would be most advantageous, they needed to stop and refuel. That quickly negates the time savings. The 747 and other subsonic trasnports had long range versions, which could make the same trips non-stop.
Other than the national airlines of the two sponsoring governments, British Airways (BOAC) and Air France, no commercial airline ever bought a Concorde. If the business case was there, the planes would have sold on their merits.
Both Boeing and Lockheed had SST development programs in the early 60s. Boeing proposed a swing-wing design (like the F111, F15, and B1), while Lockheed had a double-delta (like the XB70, SR71, and Concorde). As soon as Congress pulled the plug on federal subsidies, both these programs ended. The companies involved sold many 747s and L1011 jumbo jets, profitably and with far less taxpayer subsidy than Concorde.
Without massive subsidies from the British and French governments, Concorde would never have been. So kindly spare me the "protectionist" drivel!
Was it an engineering feat Yes! Was it presitigious? Yes! Did any company ever see fit to produce an SST using their own money? NO!
Equipment once came with real manuals. For example, old HP laser jet printers came with a thick manual that told you all about printer control language. Most people never looked at it, some were probably intimidated. But if you were a programmer who needed to write a driver for it, all the necessary information was there.
Now you get a CD with MS Windows binary drivers and a help file. No detailed information, nothing that would help you use it with anything but MS products or (perhaps) a Mac.
Battery storage is rather expensive, because batteries need replacement after 500-1000 typical (50% of charge capacity) use cycles or when they reach the end of standby service life, whichever comes first. The amortized battery costs often exceed the value of the energy (KW-Hrs) they handle through their lifetime. Thus systems requiring less battery capacity per KW output tend to be more economical.
Selling your surplus output to the power company is the way to do this, especially with a relatively constant power source (hydro). But before investing in the equipment, see if that's possible where you live. The rules vary from state to state, and sometimes even depend on what power company you deal with (public, for-profit private, or non-profit REA). You will need an approved "utility-interactive" coupling device before you connect it to the grid, to ensure your power feed doesn't endanger workers repairing a "dead" line. Because of that safety implication, only Listed equipment will be approved for that application.
This channel-hogging system is just as bad as using high-power amplifiers to blow other users off the channel. "My system is the only one that counts. I won't share with anybody else." It takes many times its fair share of a limited resource, ignoring a deliberate design strategy to use limited power (range) and reduced bandwidth. That design strategy exists to enable cooperative sharing of the available spectrum. The parallels to the me-first hooliganism on 27MHz Citizen's Band are frightening. Without cooperation and compliance to established standards and regulations, the range and through-put arms race will make wireless LANs useless to everyone.
Some of the speeders, after they learn about the red-light trick, will assume every red light is fake and blast right on through. I can see this increasing the rate of accidents caused by failing to stop for the red. You must take human nature into account: behavior will adapt in the ways other than those intended.
Consider the Milhous Nixon Memorial Double-Nickel Speed Limit. Traffic speeds didn't stay low for long after it was enacted. Three decades later we have a generation of drivers who assume that every speed limit is 10-20MPH too low. Interstate, mountain road, residential area--they zip through all of them well over the posted limit, bringing us right back to problem these radar-red-lights are trying to solve. Here we go repeating past mistakes...
I may be stopping your right to receive a call, but if your phone is licensed in the US under our FCC laws, your phone must accept any interference, which may cause undesired operation.
Not true in the case of cell phones. These are licensed devices, with the service provider being the FCC licensee. Unlike unlicensed (Part 15) devices, cell phones do have legal protection from interference. Unless the denial-of-service device is owned and operated by the licensee (cell service provider), the FCC probably will issue a Cease & Desist order (at the least) if somebody files a formal complaint about it. The cell phone companies paid huge fees for their licenses, and they aren't about to let somebody else deprive them of their licensed airspace.
IMO, the biggest problem with cell-phones in cars (and elsewhere) is that they ring. If the phone rings while you're driving, you take the eyes off traffic, find the phone, flip it open, and answer. The noise is distracting (we modern folk seem to have Pavlovian conditoning that we must answer the phone NOW!). Then there's the fumbling in the console, purse, etc. to get to the ringing phone. Then you're expected to carry on a conversation in a situation not of your choosing, such as when negotiating a highway interchange in heavy traffic. Stop the ringer, and the cell phone is much safer on the highway. Or let your passenger take the call ("Honey, I'll take the call while you drive. OK?").
(0) Get your employer to agree to cancel the anti-compete clauses, NDA, IP assignments, etc. that you signed the first day on the job. After all, if you're not valuable enough to keep on the payroll, there's no way you're a business threat to them, right? Considering how they're treating you, all I can say is good luck!
"Ten years out, in terms of actual hardware costs you can almost think of hardware as being free -- I'm not saying it will be absolutely free --...." For as long as there have been personal computers, from the Altair, through the Apple ][ , CP/M, IBM PC, and the present crop of 3+GHz WIntel boxes, there has been surprisingly little change in the price tag. For every advance along Moore's Law, there is the corresponding penalty from Parkinson's Law as applied to software (code will expand to consume all available storage, CPU cycles, and IO bandwidth). Instead of doing the same job for less money, we pay the same price for better performing hardware--and waste it by plastering ever-larger piles of form over the same humble substance.
Mr. Gates has given us a roadmap for how the next generation of super-systems will be burdened with ever more complex code, giving the user productivity similar to VisCalc running on a 4.88MHz 8088 with 256K memory. I see no compelling need to empty my bank account of another $1-2K, just to turn my old system into a disposal problem. The biggest fear of Gate's empire is the day customers just say no and step off the "upgrade" treadmill.
The only mass transit method that seems realy viable as an alterative to cars is high speed trains I'm talking about 150mph+ they can reduce the commuting time and arent subject to traffic as they use highly regulated and planed routes.
This moves the traffic and parking problems from downtown to the high-speed train stations. High speed rail lines need widely spaced stops; the train's high peak speed is wasted each time the train must brake, wait for passengers to board and disembark, and re-accelerate back to cruising speed. This is the same phenomenon that makes a 15MPH bicycle competitive with a 35MPH city bus: the bus stops often, spending less time running at "normal" speed.
So more passengers must travel longer average distances to each widely-spaced train station. The time saving is real only if the downtown area is so crowded that travel by automobile is impractical (as in Manhattan or downtown San Francisco). Thus the rail line originally intended to relieve congestion, in the long term, causes congestion to propogate to outlying areas. Just like Long Island, New Jersey, Connecticut, and the East Bay. The only real solution to congestion is to avoid requiring so many people to travel at the same time, to the same destinations, over such long distances. Sadly, that much-touted benefit of the information age remains a mirage for most of the working population.
As any good legislator knows, when you can't stop it, tax it! The government is happy to take money from buyers of booze, tobacco, guns 'n ammo, gasoline, tires, etc. So why not tax the gambling proceeds? They already take 50% up-front vigorish from lottery ticket sales, and then stick you with income tax if you win. Just apply the Alternative Minimum Tax to gambling winnings, and watch the cash roll in to the treasury.
...computers cannot kill or injure people. cars can (and do)
Traffic signal coordination. Industrial robots. CNC machine tools. Chemical plant control. Medical devices. Fly-by-wire aircraft. Cruise control/ABS systems. Airbag deployment. Note well the automotive applications, because there is a large and growing overlap between computers and automobile safety systems.
Such computers most definitely can kill people. Your desktop PC probably doesn't have that ability but millions, perhaps billions of embedded systems are in safety critical applications. That's why they run carefully constructed and thoroughly tested code tailored to the application (and nothing else). That's why they have fail-safe modes and backup safety systems. That's why they don't use a general-purpose OS and "productivity" packages. It's not a question of if computers and software can be made reliable enough for critical systems; it's a matter of the will to do so. Makers of safety-critical embedded systems have taken many precautions to reduce risks of death and serious bodily injury. The question is, when will makers of general-purpose software acknowledge their duty to prevent product defects that can cause serious financial harm?
The common thread: product liability. The best of the imperfect solutions known to date: certification to industry standards by a reputable independent expert. Certification by a third party won't absolve the supplier of liability, but failing to have it may doom you in a lawsuit (see "negligence" and "due diligence").
A more sensible contract would offer, for example, a minimum number of upgrades as well as a term. So the contract could cover, say, two upgrades minimum or all upgrades for two years (whichever comes last). Without the either/or wording, the supplier could either drag out the deliveries beyond the expiration date of fixed-term contracts, or deliver upgrades in smaller pieces to fulfill a fixed-number contract. The existing support agreement follows the same one-sided theme as the EULA: you pay your money, maybe you get something in return, or maybe you don't. Just don't ask for your money back.
Kodak suffered a huge patent loss to Polaroid about 15 years ago. Kodak had to pay a large settlement to Polaroid, had to discontinue sale and production of their "instant camera" film, and gave significant discounts as compensation to the owners of suddenly obsolete Kodak cameras. Perhaps the pain of those events has encouraged Kodak to be more aggressive defending their own patents.
His best work was the Dangerous Visions series. These were anthologies of short stories, edited by Ellison. The TV review columns he wrote for Rolling Stone are amusing in retrospect, though perhaps not so much so to the author. We've all done things we'd like to forget about.
What isn't so special is the sharing. A DSL line is yours alone, so while its data rate isn't as fast it works pretty well in actual use.
BPL has the same sharing problems as a cable modem, but with a lower data rate available for sharing. The overall throughput (in bits/sec) depends on both the transmission bandwidth (in Hz) and the signal-to-noise ratio (in dB). BPL suffers compared to cable both in the frequency response and in the noise level.
Being unshielded, BPL also must run at lower signal levels than cable to comply with FCC interference limits. There also are many noise sources on the power grid (which is why you put a power filter/surge supressor on the computer).
If BPL attracts enough subscribers to pay for the equipment and line upgrades, the performance won't be the "broadband nirvana" alluded to in the press. And unlike cable modems (where they can re-allocate an unpopular video channel for downstream data), there's no easy way to significantly increase BPL speeds. It really looks like a technological dead-end. It's time to quit dilly-dallying with makeshift solutions, and start stringing fiber to the home!
One who applies the material studied to pass the license test probably has more real electronics knowedge than the typical sophomore EE major. He may not ace the midterms, but who do they ask for help when it's time for the lab classes? Somebody who has used the test equipment before. Somebody who knows what a cold solder joint looks like. Not every ham will be a good EE, and not every good EE was a ham--but the correlation is stronger than mere coincidence. Just because you have a degree doesn't mean you're qualified.
Calculate the input impedance and frequency response of a Tschebeychev low-pass filter filter. Now do it again, with real component values for parts you can actually buy. Connect that filter to a frequency-variant complex load through a real transmission line (not the easy ideal one from your textbook). Calculate the new input impedance and frequency response. Now match it to the proper load line for your output transistor. Is that not appreciable math?
Just because you don't have to know the math to pass the test doesn't mean math isn't involved. The license is only the starting point--your chance to get your hands dirty and really learn about the technology--or you can sit on your butt, play with your toys, and vegetate. You can do that with voice, or a keyboard, or Morse code, or a computer; the tools and techniques make no difference. What does matter is the motivation to work at learning something.
If the license is the means to an end, the first waypoint on a journey of learning and discovery, then it's doing something for you. Something that is one of the core reasons Amateur Radio exists.
If it's the end in and of itself, a mere formality to be dealt with with as quickly as possible, then you'll get out of it what you put into it. Diddley-squat.
Like sports, music lessons, computer programming, drama clubs...Ham Radio won't make a star of somebody who lacks the talent and motivation to do so. But it is a way to challenge and nurture those who do have the potential, the curiosity, and the motivation to pursue electronic technology.
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That is why you need a high voltage DC-rated fuse, as close to the battery terminal as possible. An electronic breaker is not as safe (it can fail stuck on), and a mechanical circuit breaker for high voltage/high current DC circuits is unbelievably expensive. This fuse is about the size of a beer can, not your ordinary 3AG or ATC fuse for a 12V circuit. There's a case to be made for an external kill switch, too (if they can make it vandal-resistant, but quickly accessible to the rescue squad).
The shuttle was a big, expensive, funded hammer, so other programs became its nails as a survival tactic. Hubble could gave been designed differently. But if it had, it likely would have been a budget victim and never flown.
These hopelessly ineffective anti-spam "services" fail to consider the impact of their business methods on the poor users. Every one is different. Every one wants you to do a Special Thing to prove your innocence. Every week someone else decides they have the ultimate solution to spam. They are a collective nuisance, both because of the meta-spam challenges their systems produce and because they needlessly delay mail delivery. And they never worry about what happens when dozens of others are trying to do the same thing in different ways.
If you want to harvest live email addresses, grabbing them from replies to an anti-spam "service" would be a great way to go. If you want to have people foolishly click a link exploiting the latest buffer-overflow vulnerability, an anti-spam "service" message should produce lots of hits.
Attention clueless anti-spam entrepeneurs: I don't know you. I don't trust you. I won't click your handy verify link. And I certainly won't pay you any protection money!
The range wasn't adequate for non-stop trans Pacific routes. On these long distance routes where Mach 2 speed would be most advantageous, they needed to stop and refuel. That quickly negates the time savings. The 747 and other subsonic trasnports had long range versions, which could make the same trips non-stop.
Other than the national airlines of the two sponsoring governments, British Airways (BOAC) and Air France, no commercial airline ever bought a Concorde. If the business case was there, the planes would have sold on their merits.
Both Boeing and Lockheed had SST development programs in the early 60s. Boeing proposed a swing-wing design (like the F111, F15, and B1), while Lockheed had a double-delta (like the XB70, SR71, and Concorde). As soon as Congress pulled the plug on federal subsidies, both these programs ended. The companies involved sold many 747s and L1011 jumbo jets, profitably and with far less taxpayer subsidy than Concorde.
Without massive subsidies from the British and French governments, Concorde would never have been. So kindly spare me the "protectionist" drivel! Was it an engineering feat Yes! Was it presitigious? Yes! Did any company ever see fit to produce an SST using their own money? NO!
Now you get a CD with MS Windows binary drivers and a help file. No detailed information, nothing that would help you use it with anything but MS products or (perhaps) a Mac.
Selling your surplus output to the power company is the way to do this, especially with a relatively constant power source (hydro). But before investing in the equipment, see if that's possible where you live. The rules vary from state to state, and sometimes even depend on what power company you deal with (public, for-profit private, or non-profit REA). You will need an approved "utility-interactive" coupling device before you connect it to the grid, to ensure your power feed doesn't endanger workers repairing a "dead" line. Because of that safety implication, only Listed equipment will be approved for that application.
This channel-hogging system is just as bad as using high-power amplifiers to blow other users off the channel. "My system is the only one that counts. I won't share with anybody else." It takes many times its fair share of a limited resource, ignoring a deliberate design strategy to use limited power (range) and reduced bandwidth. That design strategy exists to enable cooperative sharing of the available spectrum. The parallels to the me-first hooliganism on 27MHz Citizen's Band are frightening. Without cooperation and compliance to established standards and regulations, the range and through-put arms race will make wireless LANs useless to everyone.
Consider the Milhous Nixon Memorial Double-Nickel Speed Limit. Traffic speeds didn't stay low for long after it was enacted. Three decades later we have a generation of drivers who assume that every speed limit is 10-20MPH too low. Interstate, mountain road, residential area--they zip through all of them well over the posted limit, bringing us right back to problem these radar-red-lights are trying to solve. Here we go repeating past mistakes...
Not true in the case of cell phones. These are licensed devices, with the service provider being the FCC licensee. Unlike unlicensed (Part 15) devices, cell phones do have legal protection from interference. Unless the denial-of-service device is owned and operated by the licensee (cell service provider), the FCC probably will issue a Cease & Desist order (at the least) if somebody files a formal complaint about it. The cell phone companies paid huge fees for their licenses, and they aren't about to let somebody else deprive them of their licensed airspace.
IMO, the biggest problem with cell-phones in cars (and elsewhere) is that they ring. If the phone rings while you're driving, you take the eyes off traffic, find the phone, flip it open, and answer. The noise is distracting (we modern folk seem to have Pavlovian conditoning that we must answer the phone NOW!). Then there's the fumbling in the console, purse, etc. to get to the ringing phone. Then you're expected to carry on a conversation in a situation not of your choosing, such as when negotiating a highway interchange in heavy traffic. Stop the ringer, and the cell phone is much safer on the highway. Or let your passenger take the call ("Honey, I'll take the call while you drive. OK?").
(0) Get your employer to agree to cancel the anti-compete clauses, NDA, IP assignments, etc. that you signed the first day on the job. After all, if you're not valuable enough to keep on the payroll, there's no way you're a business threat to them, right? Considering how they're treating you, all I can say is good luck!
Mr. Gates has given us a roadmap for how the next generation of super-systems will be burdened with ever more complex code, giving the user productivity similar to VisCalc running on a 4.88MHz 8088 with 256K memory. I see no compelling need to empty my bank account of another $1-2K, just to turn my old system into a disposal problem. The biggest fear of Gate's empire is the day customers just say no and step off the "upgrade" treadmill.
This moves the traffic and parking problems from downtown to the high-speed train stations. High speed rail lines need widely spaced stops; the train's high peak speed is wasted each time the train must brake, wait for passengers to board and disembark, and re-accelerate back to cruising speed. This is the same phenomenon that makes a 15MPH bicycle competitive with a 35MPH city bus: the bus stops often, spending less time running at "normal" speed.
So more passengers must travel longer average distances to each widely-spaced train station. The time saving is real only if the downtown area is so crowded that travel by automobile is impractical (as in Manhattan or downtown San Francisco). Thus the rail line originally intended to relieve congestion, in the long term, causes congestion to propogate to outlying areas. Just like Long Island, New Jersey, Connecticut, and the East Bay. The only real solution to congestion is to avoid requiring so many people to travel at the same time, to the same destinations, over such long distances. Sadly, that much-touted benefit of the information age remains a mirage for most of the working population.
As any good legislator knows, when you can't stop it, tax it! The government is happy to take money from buyers of booze, tobacco, guns 'n ammo, gasoline, tires, etc. So why not tax the gambling proceeds? They already take 50% up-front vigorish from lottery ticket sales, and then stick you with income tax if you win. Just apply the Alternative Minimum Tax to gambling winnings, and watch the cash roll in to the treasury.
Am I the only one who finds it ironic that the linked article requests a cookie good for over 30 years?
Traffic signal coordination. Industrial robots. CNC machine tools. Chemical plant control. Medical devices. Fly-by-wire aircraft. Cruise control/ABS systems. Airbag deployment. Note well the automotive applications, because there is a large and growing overlap between computers and automobile safety systems.
Such computers most definitely can kill people. Your desktop PC probably doesn't have that ability but millions, perhaps billions of embedded systems are in safety critical applications. That's why they run carefully constructed and thoroughly tested code tailored to the application (and nothing else). That's why they have fail-safe modes and backup safety systems. That's why they don't use a general-purpose OS and "productivity" packages. It's not a question of if computers and software can be made reliable enough for critical systems; it's a matter of the will to do so. Makers of safety-critical embedded systems have taken many precautions to reduce risks of death and serious bodily injury. The question is, when will makers of general-purpose software acknowledge their duty to prevent product defects that can cause serious financial harm?
The common thread: product liability. The best of the imperfect solutions known to date: certification to industry standards by a reputable independent expert. Certification by a third party won't absolve the supplier of liability, but failing to have it may doom you in a lawsuit (see "negligence" and "due diligence").
A more sensible contract would offer, for example, a minimum number of upgrades as well as a term. So the contract could cover, say, two upgrades minimum or all upgrades for two years (whichever comes last). Without the either/or wording, the supplier could either drag out the deliveries beyond the expiration date of fixed-term contracts, or deliver upgrades in smaller pieces to fulfill a fixed-number contract. The existing support agreement follows the same one-sided theme as the EULA: you pay your money, maybe you get something in return, or maybe you don't. Just don't ask for your money back.
Kodak suffered a huge patent loss to Polaroid about 15 years ago. Kodak had to pay a large settlement to Polaroid, had to discontinue sale and production of their "instant camera" film, and gave significant discounts as compensation to the owners of suddenly obsolete Kodak cameras. Perhaps the pain of those events has encouraged Kodak to be more aggressive defending their own patents.
His best work was the Dangerous Visions series. These were anthologies of short stories, edited by Ellison. The TV review columns he wrote for Rolling Stone are amusing in retrospect, though perhaps not so much so to the author. We've all done things we'd like to forget about.
BPL has the same sharing problems as a cable modem, but with a lower data rate available for sharing. The overall throughput (in bits/sec) depends on both the transmission bandwidth (in Hz) and the signal-to-noise ratio (in dB). BPL suffers compared to cable both in the frequency response and in the noise level.
Being unshielded, BPL also must run at lower signal levels than cable to comply with FCC interference limits. There also are many noise sources on the power grid (which is why you put a power filter/surge supressor on the computer).
If BPL attracts enough subscribers to pay for the equipment and line upgrades, the performance won't be the "broadband nirvana" alluded to in the press. And unlike cable modems (where they can re-allocate an unpopular video channel for downstream data), there's no easy way to significantly increase BPL speeds. It really looks like a technological dead-end. It's time to quit dilly-dallying with makeshift solutions, and start stringing fiber to the home!
Calculate the input impedance and frequency response of a Tschebeychev low-pass filter filter. Now do it again, with real component values for parts you can actually buy. Connect that filter to a frequency-variant complex load through a real transmission line (not the easy ideal one from your textbook). Calculate the new input impedance and frequency response. Now match it to the proper load line for your output transistor. Is that not appreciable math?
Just because you don't have to know the math to pass the test doesn't mean math isn't involved. The license is only the starting point--your chance to get your hands dirty and really learn about the technology--or you can sit on your butt, play with your toys, and vegetate. You can do that with voice, or a keyboard, or Morse code, or a computer; the tools and techniques make no difference. What does matter is the motivation to work at learning something.
If the license is the means to an end, the first waypoint on a journey of learning and discovery, then it's doing something for you. Something that is one of the core reasons Amateur Radio exists.
If it's the end in and of itself, a mere formality to be dealt with with as quickly as possible, then you'll get out of it what you put into it. Diddley-squat.
Like sports, music lessons, computer programming, drama clubs...Ham Radio won't make a star of somebody who lacks the talent and motivation to do so. But it is a way to challenge and nurture those who do have the potential, the curiosity, and the motivation to pursue electronic technology.