This defilement of the English language only underscores my advice to all: Do not use a word, either spoken or written, until you've seen it used properly in a sentence.
Because people with nukes don't do stupid things...
Have you forgotten the little Indian/Pakistani pissing match involving nukes? I'd hardly consider that responsible; it sounds more like stupid to me. They may not have been used against one another, but we sure as hell didn't need that sort of "mine's bigger than yours" posturing with live nukes around. For that matter, I'm sure the world could've done without the nuclear fallout from those tests as well.
Have they determined if falcarinol inhibits all preneoplastic lesions, or just those induced with azoxymethane?
Also, there's a greek mu missing in the text of the parent post. It sould read "35 ug" instead of "35 g". They're pretty good if they can find carrots with "... a natural content of 35 g falcarinol/g"!
Ok, I'll give it a go. Lasers are not point sources - the formula you used is for an isotropic radiator, not a beam source. You'd need to know the divergence of the laser to calculate the power/m2 at the satellite. Also, your peak pulse power is off by about a factor of 10-20 (or more...)
Say the beam half-angle divergence of your 250 kW laser is 1 milliradian (mrad) (pretty crappy). At 35,000 km, the beam will be at least 35*tan(0.001)*2 = 70 km wide. That's only 65 uW/m2. Not even bright, much less cripplin'.
Increase the intensity of the beam to 5 MW and reduce the divergence to.25 mrad, and you get a beam 8750*2 = 17.5 km across and a power density of only 20 mW/m2. That's less than a class II supermarket scanner laser.
Damaging a geostationary sat is hard with a laser!
... sounds huge but could be as "little" as 1.52x in the +X, -X, +Y, -Y and +Z directions. With antennas that don't radiate appreciably outside the horizontal plane it could be as much as 1.68x. ("Coverage" probably infers either the area or volume of signal).
A nit, I know, but an important one. Length is not a factor in the characteristic impedance of a cable. The impedance of a cable (by which you mean its total impedance) is related to length. The original article was confusing characteristic impedance, impedance/ft, capacitance/ft, resistance, and loss per foot.
That's 'speelchekur', you dummy! Where'd you learn to speel?
Re:I had one of these!!!
on
A USB Typewriter?
·
· Score: 2, Informative
Not to reply to myself 8-), but check out this article. An excerpt:
The more clever (IMHO) mod was to attach seven solenoids to the Selectric between the keyboard encoding mechanism and the print mechanism, to directly control the tilt and rotate. And two more for the carriage return and paper advance. This has the advantage that you can still use it as a typewriter without having to attach and remove the solenoid box, and it's potentially less expensive since it takes nowhere near as many solenoids. I seem to recall that Don Lancaster wrote a do-it-yourself article about this approach.
I scrounged a reservation system from Holiday Inn back in the 80's. It was in part an IBM Selectric typewriter with little solenoids that pushed on (five or six, I don't remember) little bars in different combinations that controlled what characters were printed. This would be pretty easy to (re-)implement. Try All Electronics or some other surplus store for solenoids, etc.
The emitted signal doesn't have to be very strong at all - since it appears on all channels, it's probably on the IF freq - 45 MHz.
Historically VCRs have been very suseptible to RF interference from Amateur Radio Operators using 2-30MHz signals. The head is quite good at receiving such freqs. Remember that there are two sides to this issue - the emitted signal strength and the TV's suseptibility to undesired signals. It takes both to prevent interference. Most electronics these days are poorly shielded at best.
I doubt seriously this will happen. Here's a link to the DS's FCC Certification Report. Just because a part 15 device impacts a non-part 15 device doesn't mean it is not operating within spec. All it means is that the part 15 device must be moved, turned off, etc to eliminate the objectionable interference. Read that little FCC label on the DS (or in the manual). Note that the DS user and TV owner are the same person in this case. They can choose to play and accept the interference or turn off either the DS or TV. My guess is that the DS can't interfere far enough away to cause a neighbor's TV to show interference, so the product probably won't cause harmful interference to anyone but its owner, and only right next to a TV.
Let me get this straight: the military has a general that is in charge "doe snot screening"? Or do they have a general in charge of something called a "doe snot screen?" What in the world would they use a screen like that for, and why must they put a general in charge of it? It must be a new secret weapon.
Agreed. I didn't say you conclusions were wrong, just the insolation level. In fact, after doing the math, your conclusion still stands.
Remember that the level I quoted was for absolutely clear, sun directly overhead conditions. Over the course of 24 hours you've got 50% dark, and the insolation level during daylight would vary sinusoidally from 0 -> 100 -> 0 percent. The actual useful daily power available before conversion losses would probably be 12 hours *.707 (rms sunlight) * 1 kW/m2 = 8.5 kW*hr/m2. Even with 20% efficient solar panels (or furnaces), your're looking at around 1.7 kW*hr/m2.
The total US energy use in 1998 was 94.27 Quad, which equals 27.6 x10^12 kW*hr. A day's worth of that is 44.5x10^9 kW*hr. That would require 26.2x10^9 m2 of land - 6.5 million acres or a little over 10,000 square miles of collectors. Assuming land and water area, that as big as Massachusetts. If you consider land only, that's 10% larger than Maryland. Oddly, it would be about 10% of either Arizona, Nevada, or New Mexico.
The choice of 2450 MHz has more to do with it being in an ISM (Industrial, Scientific, Medical) band where powerful magnetrons were plentiful and leakage regs are way more relaxed. The article you quote points this out down in the blue text labeled "Dan Writes..."
Water's absorption of approx.001 dB/km at 2450 MHz is not particularly high compared to a local maximum of.1 dB/km at 22 GHz or a whopping 25 dB/km at 180 and 300 GHz. The numerical ratio of A(300GHz):A(2.45GHz) is something like 316:1. See this chart for a graph of water vapor and oxygen attenuation vs frequency.
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Thanks for the freak-fest, B3ryllium!
give in to the power of the tea.
See you at the d-a-i-y-e spa!
This defilement of the English language only underscores my advice to all: Do not use a word, either spoken or written, until you've seen it used properly in a sentence.
One of my favorites: "walla" instead of "voila".
Send her a handheld microfiche reader that runs off of 120VAV, 12VDC, or ambient light. Fiche-ify the books, voila!!
Because people with nukes don't do stupid things...
Have you forgotten the little Indian/Pakistani pissing match involving nukes? I'd hardly consider that responsible; it sounds more like stupid to me. They may not have been used against one another, but we sure as hell didn't need that sort of "mine's bigger than yours" posturing with live nukes around. For that matter, I'm sure the world could've done without the nuclear fallout from those tests as well.
Have they determined if falcarinol inhibits all preneoplastic lesions, or just those induced with azoxymethane?
Also, there's a greek mu missing in the text of the parent post. It sould read "35 ug" instead of "35 g". They're pretty good if they can find carrots with "... a natural content of 35 g falcarinol/g"!
There are some pretty funny new movie titles in there:
That's similar to how calico cats happen, like mine, named Opal. Her brother is named Onyx, appropriately enough.
I couldn't agree more - this isn't cold fusion, it's hot 'nano-fusion'. Let's start using the new name and see if it catches on.
Correct my physics!
Ok, I'll give it a go. Lasers are not point sources - the formula you used is for an isotropic radiator, not a beam source. You'd need to know the divergence of the laser to calculate the power/m2 at the satellite. Also, your peak pulse power is off by about a factor of 10-20 (or more...)
Say the beam half-angle divergence of your 250 kW laser is 1 milliradian (mrad) (pretty crappy). At 35,000 km, the beam will be at least 35*tan(0.001)*2 = 70 km wide. That's only 65 uW/m2. Not even bright, much less cripplin'.
Increase the intensity of the beam to 5 MW and reduce the divergence to .25 mrad, and you get a beam 8750*2 = 17.5 km across and a power density of only 20 mW/m2. That's less than a class II supermarket scanner laser.
Damaging a geostationary sat is hard with a laser!
My goodness, what a mess! 'Nuff said.
You mean like this one in rural Bath County, Virginia?
I've visited it - it's quite impressive.
... sounds huge but could be as "little" as 1.52x in the +X, -X, +Y, -Y and +Z directions. With antennas that don't radiate appreciably outside the horizontal plane it could be as much as 1.68x. ("Coverage" probably infers either the area or volume of signal).
Length is not a factor in impedance of a cable.
A nit, I know, but an important one. Length is not a factor in the characteristic impedance of a cable. The impedance of a cable (by which you mean its total impedance) is related to length. The original article was confusing characteristic impedance, impedance/ft, capacitance/ft, resistance, and loss per foot.
Historically VCRs have been very suseptible to RF interference from Amateur Radio Operators using 2-30MHz signals. The head is quite good at receiving such freqs. Remember that there are two sides to this issue - the emitted signal strength and the TV's suseptibility to undesired signals. It takes both to prevent interference. Most electronics these days are poorly shielded at best.
I doubt seriously this will happen. Here's a link to the DS's FCC Certification Report. Just because a part 15 device impacts a non-part 15 device doesn't mean it is not operating within spec. All it means is that the part 15 device must be moved, turned off, etc to eliminate the objectionable interference. Read that little FCC label on the DS (or in the manual). Note that the DS user and TV owner are the same person in this case. They can choose to play and accept the interference or turn off either the DS or TV. My guess is that the DS can't interfere far enough away to cause a neighbor's TV to show interference, so the product probably won't cause harmful interference to anyone but its owner, and only right next to a TV.
And Bob Fosse was a choreographer.
And a Chorale is "a hymn or psalm sung to a traditional or composed melody in church."
Gotta love those homophones!
The military doe snot screen general...
Let me get this straight: the military has a general that is in charge "doe snot screening"? Or do they have a general in charge of something called a "doe snot screen?" What in the world would they use a screen like that for, and why must they put a general in charge of it? It must be a new secret weapon.
Agreed. I didn't say you conclusions were wrong, just the insolation level. In fact, after doing the math, your conclusion still stands.
Remember that the level I quoted was for absolutely clear, sun directly overhead conditions. Over the course of 24 hours you've got 50% dark, and the insolation level during daylight would vary sinusoidally from 0 -> 100 -> 0 percent. The actual useful daily power available before conversion losses would probably be 12 hours * .707 (rms sunlight) * 1 kW/m2 = 8.5 kW*hr/m2. Even with 20% efficient solar panels (or furnaces), your're looking at around 1.7 kW*hr/m2.
The total US energy use in 1998 was 94.27 Quad, which equals 27.6 x10^12 kW*hr. A day's worth of that is 44.5x10^9 kW*hr. That would require 26.2x10^9 m2 of land - 6.5 million acres or a little over 10,000 square miles of collectors. Assuming land and water area, that as big as Massachusetts. If you consider land only, that's 10% larger than Maryland. Oddly, it would be about 10% of either Arizona, Nevada, or New Mexico.
The choice of 2450 MHz has more to do with it being in an ISM (Industrial, Scientific, Medical) band where powerful magnetrons were plentiful and leakage regs are way more relaxed. The article you quote points this out down in the blue text labeled "Dan Writes..."
Water's absorption of approx .001 dB/km at 2450 MHz is not particularly high compared to a local maximum of .1 dB/km at 22 GHz or a whopping 25 dB/km at 180 and 300 GHz. The numerical ratio of A(300GHz):A(2.45GHz) is something like 316:1. See this chart for a graph of water vapor and oxygen attenuation vs frequency.
... when it stands up and says, "Feed me, Seymour!"