An HDTV signal uses the same amount of space (6 MHz) as an NTSC (analog) signal. The advantage of HDTV is that the active channels can be more closely packed together, saving a great deal of spectrum. With the current system, each active TV transmitter makes several additional channels unusable for TV broadcasting due to interference concerns. That is why there are such wide gaps in the channel assignments of television stations.
There are several problems with adding an escape rocket system, like that used on early manned missions.
One, it adds complexity and risk. There are more things that can break and you are adding more pyrotechnic systems to the launch vehicle. There are structural problems. On most launch vehicles, the spacecraft is covered by a fiberglass fairing. This is strong enough to protect the spacecraft from the air flowing over the launch vehicle. It would need a lot of reinforcement, which adds weight, to support the load of an escape tower and the forces it would have to deal with if the escape rockets were fired.
Two, due to aerodynamics, there is a limited time that the system can be used. Once you exceed a certain speed, the escape system will not work.
Three, assuming the escape system works, where is the spacecraft going to land? If it is over water, you need a flotation system and enough ships and aircraft to recover the spacecraft in a reasonable amount of time. How much damage to the spacecraft is going to be incurred by the escape, landing and salt water?
History says that you should never put your satellite on the first launch of a new launch vehicle, or the first launch of a substantially modified launch vehicle. The odds are that your satellite will need an underwater tracking beacon.
There was nothing wrong with the software, as long as it was being used on an Ariane-4. The problem was that the software was not properly modified and tested before being used on Ariane-5. The flight profile of the Ariane-5 was significantly different than the Ariane-4, which caused the software to fail. Think of it as reusing the engine controller from a 2.0 liter engine on a supercharged 3.0 liter engine, without revisiting the assumptions made about engine characteristics in the original software.
NASA does not manage the ELV (expendable launch vehicle) programs, such as Atlas, Delta and Pegasus. These are run and funded by private companies. NASA's involvement is limited to contracting for launch services, just like any other customer, and providing limited launch support from its ground and space network of tracking stations/satellites.
Beware of statistics on children killed by guns. Usually they don't differentiate between the 10-year old who accidentally shoots his sister with daddy's pistol and the 17-year old gang banger who gets shot by the owner of a liquor store while attempting an armed robbery.
There used to be a large sheet music industry, back when many middle-class people had pianos in their homes. Then there were rolls for player pianos and early forms of audio recordings.
Musicians were paid for performing.
In earlier days, composers taught students, had patrons, or had jobs as music directors or choir masters in a church.
U.S. government employees, and contractors, can obtain patents for inventions that are the result of government funded research. You may be thinking of copyrights. The work of a U.S. government employee can not be copyrighted, it is in the public domain.
Some of their computers were clones of popular U.S. computers such as the IBM 360, PDP-11 and VAX.
Many years ago, I heard a rumor about a VAX-11/780 (first model of the VAX) disappearing while being shipped on a train in West Germany. Supposedly it was taken to East Germany for reverse engineering.
NT ran in a crippled 32-bit mode on the Alpha. It did not support 64-bit applications.
Diesel Cars
on
239 MPG Car
·
· Score: 3, Interesting
I knew several people who bought diesel cars during the last fuel crunch. They liked the mileage but were unhappy with the high incidence of mechanical problems and the difficulty with finding diesel pumps at gas stations. They switched back to gasoline for their subsequent cars.
It may be ATI's policy that the OEMs are responsible for modifying (if needed), testing, and distributing the drivers for their cards. The presence of an ATI video chip does not mean that the board is compatible with an ATI video board. Many OEMs make minor or major tweaks to the reference designs that their cards are based on. They may even design their card from scratch. It is the OEM's responsibility to provide drivers for the cards that they sell. Unfortunately, many OEMs are unwilling or unable to properly support their products, that costs money, which could help pay for the CEO's new airplane.
While the INS may not be implementing this in the best way, the U.S. government has a legitimate interest in getting information from visa applicants and keeping track of foreign nationals who are residing in the United States. There are a lot of people who misuse or overstay their visa. In the past, the INS has been extremely lax about the enforcement of immigration law.
It is common for the unshielded speaker wires on audio systems to behave as antennas. The received signals are coupled into the final amplifier stage of the device that is driving the speakers, where they are detected and converted into audio frequency signals that you can hear, sort of like an old crystal radio.
The ARRL has a web page with some information on the subject.
You might ask the engineer at the local radio station for suggestions. Even though it is not the radio station's fault, he may be willing to offer some assistance. Local amateur radio clubs can also be sources of people who are willing to help.
Ask the support department of the manufacturer of your audio device for assistance. They may have technical bulletins on how to solve the problem.
If you are asking people for help, be nice, not confrontational. Remember that it is your audio equipment, not the radio station, that is at fault. Consumer electronic equipment manufacturers could avoid most of these problems by adding less than a dollars worth of parts to their equipment. Most do not, reasoning that it is cheaper to deal with some complaints of susceptibility to RF interference than to prevent the problem.
Avoiding the "bomb down your shorts" is one of the reasons that the military has been developing and using spread spectrum communications for many years. With DSSS (direct sequence spread spectrum) and a high chip rate, the carrier is spread over a wide swath of spectrum. It can actually be below the noise floor. If you look for the signal with a spectrum analyzer, the most that you will see is a small elevation in the noise level. The tricky part of this is synchronizing the sequence generators in the transmitter and receiver.
I've noticed this problem with many local retail stores. If their server or network connection goes down, they have no backup manual system. It's rather frustrating to have the cash and product in your hand, only to be told that you can't buy the product because the system is down.
If you look at network diagrams of the Bell System, when AT&T still ran everything, you will see a system that was designed to cope with disasters and excessive loads. It provided a great deal of flexibility in how calls were routed through the network. Each central office had multiple links to peer central offices and parent central offices. A call could be routed in many different ways. If a link to a peer central office was out, the call could be "kicked upstairs" to a parent central office, which would route it over a different link to the destination central office. The only single points of failure were the local central office and the wires in between the local central office and the subscriber.
The U.S. Government has been "dabbling" in long-distance voice networks for decades. The government has a strong interest in having a secure and survivable long-distance voice network. AT&T worked closely with the federal government in hardening the long-distance network against natural disasters and military attack.
The WTC attack caused major damage to several Verizon central offices and a bunch of cell sites. This resulted in extensive disruption to voice and data services in lower Manhattan. According to Verizon, 3.6 million data circuits were damaged or disrupted.
You could buy a Beetle for less than $2000 back then. A Rolls Royce started at about $20,000, about the same price as a new single-family house in what was to become Silicon Valley. Isn't inflation wonderful?
I used to use a multi-user BBS (Bernard Klatt's 8BBS) that ran on OS/8. I thought it was multi-user but that may have just been the BBS software, not the operating system.
6-bit character codes were popular before the introduction of ASCII (7-bit) and EBCDIC (8-bit). The PDP-10 had a 36-bit word, which could hold 6 6-bit characters. It also supported other character codes, such as ASCII.
If you look at old assemblers and compilers, the limit on the length of a symbol/variable name is often the number of characters that could be squeezed into a single machine word.
Slashdot Mirror
An HDTV signal uses the same amount of space (6 MHz) as an NTSC (analog) signal. The advantage of HDTV is that the active channels can be more closely packed together, saving a great deal of spectrum. With the current system, each active TV transmitter makes several additional channels unusable for TV broadcasting due to interference concerns. That is why there are such wide gaps in the channel assignments of television stations.
One, it adds complexity and risk. There are more things that can break and you are adding more pyrotechnic systems to the launch vehicle. There are structural problems. On most launch vehicles, the spacecraft is covered by a fiberglass fairing. This is strong enough to protect the spacecraft from the air flowing over the launch vehicle. It would need a lot of reinforcement, which adds weight, to support the load of an escape tower and the forces it would have to deal with if the escape rockets were fired.
Two, due to aerodynamics, there is a limited time that the system can be used. Once you exceed a certain speed, the escape system will not work.
Three, assuming the escape system works, where is the spacecraft going to land? If it is over water, you need a flotation system and enough ships and aircraft to recover the spacecraft in a reasonable amount of time. How much damage to the spacecraft is going to be incurred by the escape, landing and salt water?
History says that you should never put your satellite on the first launch of a new launch vehicle, or the first launch of a substantially modified launch vehicle. The odds are that your satellite will need an underwater tracking beacon.
There was nothing wrong with the software, as long as it was being used on an Ariane-4. The problem was that the software was not properly modified and tested before being used on Ariane-5. The flight profile of the Ariane-5 was significantly different than the Ariane-4, which caused the software to fail. Think of it as reusing the engine controller from a 2.0 liter engine on a supercharged 3.0 liter engine, without revisiting the assumptions made about engine characteristics in the original software.
NASA does not manage the ELV (expendable launch vehicle) programs, such as Atlas, Delta and Pegasus. These are run and funded by private companies. NASA's involvement is limited to contracting for launch services, just like any other customer, and providing limited launch support from its ground and space network of tracking stations/satellites.
Sperry Rand Univac (now UniSys) has already released an operating system called OS/3.
Beware of statistics on children killed by guns. Usually they don't differentiate between the 10-year old who accidentally shoots his sister with daddy's pistol and the 17-year old gang banger who gets shot by the owner of a liquor store while attempting an armed robbery.
355/113 is much better, plus it has a nice structure.
Musicians were paid for performing.
In earlier days, composers taught students, had patrons, or had jobs as music directors or choir masters in a church.
U.S. government employees, and contractors, can obtain patents for inventions that are the result of government funded research. You may be thinking of copyrights. The work of a U.S. government employee can not be copyrighted, it is in the public domain.
Many years ago, I heard a rumor about a VAX-11/780 (first model of the VAX) disappearing while being shipped on a train in West Germany. Supposedly it was taken to East Germany for reverse engineering.
NT ran in a crippled 32-bit mode on the Alpha. It did not support 64-bit applications.
I knew several people who bought diesel cars during the last fuel crunch. They liked the mileage but were unhappy with the high incidence of mechanical problems and the difficulty with finding diesel pumps at gas stations. They switched back to gasoline for their subsequent cars.
It may be ATI's policy that the OEMs are responsible for modifying (if needed), testing, and distributing the drivers for their cards. The presence of an ATI video chip does not mean that the board is compatible with an ATI video board. Many OEMs make minor or major tweaks to the reference designs that their cards are based on. They may even design their card from scratch. It is the OEM's responsibility to provide drivers for the cards that they sell. Unfortunately, many OEMs are unwilling or unable to properly support their products, that costs money, which could help pay for the CEO's new airplane.
While the INS may not be implementing this in the best way, the U.S. government has a legitimate interest in getting information from visa applicants and keeping track of foreign nationals who are residing in the United States. There are a lot of people who misuse or overstay their visa. In the past, the INS has been extremely lax about the enforcement of immigration law.
The ARRL has a web page with some information on the subject.
You might ask the engineer at the local radio station for suggestions. Even though it is not the radio station's fault, he may be willing to offer some assistance. Local amateur radio clubs can also be sources of people who are willing to help.
Ask the support department of the manufacturer of your audio device for assistance. They may have technical bulletins on how to solve the problem.
If you are asking people for help, be nice, not confrontational. Remember that it is your audio equipment, not the radio station, that is at fault. Consumer electronic equipment manufacturers could avoid most of these problems by adding less than a dollars worth of parts to their equipment. Most do not, reasoning that it is cheaper to deal with some complaints of susceptibility to RF interference than to prevent the problem.
"I reach for the stars, but sometimes I hit London."
-- attributed to Wernher von Braun
Avoiding the "bomb down your shorts" is one of the reasons that the military has been developing and using spread spectrum communications for many years. With DSSS (direct sequence spread spectrum) and a high chip rate, the carrier is spread over a wide swath of spectrum. It can actually be below the noise floor. If you look for the signal with a spectrum analyzer, the most that you will see is a small elevation in the noise level. The tricky part of this is synchronizing the sequence generators in the transmitter and receiver.
I've noticed this problem with many local retail stores. If their server or network connection goes down, they have no backup manual system. It's rather frustrating to have the cash and product in your hand, only to be told that you can't buy the product because the system is down.
If you look at network diagrams of the Bell System, when AT&T still ran everything, you will see a system that was designed to cope with disasters and excessive loads. It provided a great deal of flexibility in how calls were routed through the network. Each central office had multiple links to peer central offices and parent central offices. A call could be routed in many different ways. If a link to a peer central office was out, the call could be "kicked upstairs" to a parent central office, which would route it over a different link to the destination central office. The only single points of failure were the local central office and the wires in between the local central office and the subscriber.
The U.S. Government has been "dabbling" in long-distance voice networks for decades. The government has a strong interest in having a secure and survivable long-distance voice network. AT&T worked closely with the federal government in hardening the long-distance network against natural disasters and military attack.
The WTC attack caused major damage to several Verizon central offices and a bunch of cell sites. This resulted in extensive disruption to voice and data services in lower Manhattan. According to Verizon, 3.6 million data circuits were damaged or disrupted.
You could buy a Beetle for less than $2000 back then. A Rolls Royce started at about $20,000, about the same price as a new single-family house in what was to become Silicon Valley. Isn't inflation wonderful?
I used to use a multi-user BBS (Bernard Klatt's 8BBS) that ran on OS/8. I thought it was multi-user but that may have just been the BBS software, not the operating system.
If you look at old assemblers and compilers, the limit on the length of a symbol/variable name is often the number of characters that could be squeezed into a single machine word.