Maybe you should read up on fast reactors - a fast reactor is not necessarily also a breeder; a light water reactor breeds plutonium whether you want it to or not.
Also, the plutonium IFRs make is _less_ useful for weapons: "... plutonium-bearing material taken from anywhere in the IFR cycle was so ornery, because of inherent heat, radioactivity and spontaneous neutrons, that making a bomb with it without chemical separation of the plutonium would be essentially impossible - far, far harder than using today's reactor-grade plutonium."
Don't try to scare people away by bringing up terms which you don't understand. A microwatt is a lot of power at these frequencies.
I definitely understand the terms and agree that -42dBm is a useful amount of power at 60GHz. Thanks for the ad hominem.
My point is that if you've got all that power and all that real estate to run such a large and terribly inefficient signal source, what does using it actually give you?
In any real-world comms application I can think of (outside the laboratory), spatial and temporal coherence are not needed and introduce more problems that they solve. The beamwidth is narrow but is still diffraction-limited; the same limit can easily be achieved with normal high gain antennas (at 30-70GHz, high gain antennas are tiny).
If for some reason you need temporal coherence, your only choices of modulation are by direct modulation of the pump laser; that is, mixing (heterodyning) the output of the maser with a modulating signal by conventional means (semiconductor mixer, for instance) would destroy the coherence. I suppose you could do the mixing in a non-linear waveguide setup, but that would be a lot of microwave plumbing. Similar results can be achieved using regular old polarized antennas without limiting your modulation choices.
In other words, using a maser for comms is a solution looking for a problem.
In your example, a 1 watt optical laser would be at best 45% efficient. So you're looking at about 2.2 Watts input for 63 uW out. A 20 GHz DRO followed by a doubler or tripler would give you significantly more output power per unit of input power, as well as be tunable and tiny. The DRO in the link consumes a maximum of 31.7 dBm of power and emits 13 dBm of RF. an IMPATT diode would be another good choice.
I agree completely (that's why I said "Good start"), but the wild, rabid enthusiasm of other commenters need to take that into account. They obviously didn't RFTA, so they hear 'maser' and thought it meant 'death ray'.
PS - I think you may have made it onto the DEA's watch list with your phrase "crystal he cooked up in a hurry".:-)
I should have quoted this part of the article: "When configured as an oscillator, the solid-state maser’s measured output power of around 10 decibel milliwatts is approximately 100 million times greater than that of an atomic hydrogen maser, which oscillates at a similar frequency (about 1.42 gigahertz)." [emphasis mine].
I was not referring to it's gain as an amplifier; rather it's rather meager output as a 1.42 GHz oscillator. For 1.5 kW in, I'd expect at least half that much power out to be considered useful at all (that's for a solid-state or tube oscillator).
Here's a tunable VCO that uses 50mW to generate 2.5 mW from 1.277 to 1.691 GHz. That's 20:1.
The only use this thing has as an oscillator over other means are possibly frequency stability and coherence, neither of which are major concerns with regard to microwave transmission applications.
We see this in the length of antennas. To receive a signal, the antenna has to be at least a quarter wavelength. If you look at old cars that are made to receive conventional AM signals, they are longer.
Untrue. "conventional AM signals", at least in the US, are from 540kHz to 1610kHz. Wavelengths corresponding to those frequencies are 555.5m to 186m, respectively. Taking the shorter of the two, a quarter wavelength of 186m is 46.5m. I've never seen an antenna on a car that's 10x the length of the car! Any antenna, regardless of its length, can receive and frequency, it's just very inefficient to have antennas much, much shorter than the wavelength.
I think what you might mean is that for a monopole antenna to be resonant at a particular frequency, it must be an odd multiple of a quarter wavelength. Similarly, each of a dipoles's two arms must be an odd multiple of a quarter wavelength. You can add loading coils to physically-short antennas to make them resonant.
The deer population explosion is so out of hand in Virginia they should issue machine guns for deer hunting.
Take a look at the deer hunting bag limits in Virginia. When I was a kid, the big question was "will it be one buck or two for the [two week] season?" The idea of shooting a doe was out of the question. Now it's more like "how many antlerless deer MUST I shoot before I can shoot a buck?" From the URL:
The bag limit for deer shall be two a day, six a license year. Of the six deer limit, no more than three may be antlered deer and at least three must be antlerless deer.
The season in Hanover is 100% antlered or antlerless, November 17 through January 5. In some localities you can 'Earn A Buck' by whacking does. In addition, you can get crop damage and other sorts of Bonus Deer Permits that permit you to exceed the season bag limit.
If my math is correct, there are 181 hunting days between all of the special seasons statewide. If I were infinitely wealthy and took advantage of every single day of legal hunting and bonus deer tags, I could take 2 deer a day for a total of 362 deer a season!
You clearly have no clue what you're talking about.
This rifle is but one example of the hundreds that have been manufactured in.308 Winchester for 60 years now. If you read the article, you'll see that the.308 cartridge was designed in 1952 AND IS THE BASIS FOR THE MILITARY CARTRIDGE. It is wildly popular in short-action rifles for hunting large game. It is typically loaded to slightly lower muzzle energies than the longer.30-06, but is usually cheaper, and as 'short' cartridge it allows for faster follow-up shots if needed. (It also is supposedly slightly more accurate because of its length).
Sorry, you have no no clue what you're talking about. First, get educated on the subject; read up on muzzle energy vs muzzle velocity. There are many sites about reloading that have that sort of data. Then go to a range and fire a few hundred rounds each in firearms chambered for many different rounds of varying calibers and muzzle energy, and get back to us that know what we're talking about from experience.
That is legal for deer hunting in all 50 states...
But not in Hanover County, Virginia. We must use shotguns (slugs ok) or muzzle-loaders. Strangely, Hanover is a mostly-rural county; surrounding heavily-populated counties like Henrico and the City of Richmond do not have similar restrictions. [I see that Chesterfield County has joined in on the rifle ban; too bad!]
If you're profoundly bored, Virginia hunting rules can be found here and a synopsis of local regulations can be found here.
Reminds me of one of my first network hub installations (yes, hubs). The only place to mount a stack of hubs was in the furnace room - an ancient oil-fired furnace that belched soot on every startup. To say the least the innards of those hubs were _disgusting_ in a very short while.
Social Security and Medicare must be massively reformed to be means based and not handouts to everyone over 65 (who are far far richer as a group than everyone under 30).
I once did the math, and found that it would be cheaper to cut a check for $30,000 to every single US family than continue spending all that money on the various 'entitlement' programs.
I agree with your comment, although it has nothing to do with my point - I disagreed with the OP's statement that "16 bit stereo at 44.1KHz can accurately reproduce frequencies up to 22.05KHz". I was not making any assertions with regard to the need to have content at those frequencies. In addition to the points I made earlier, if your so-called 'brick wall' filter isn't particularly good at eliminating (possibly spurious) content above the Nyquist limit, that content will fold back into the audible spectrum, adding to audible noise.
So you do mean Legion. Wikipedia says "Legio in Latin means Legion." I've always heard that Biblical quote in English, and it does use the word 'legion'.
16 bit stereo at 44.1KHz can accurately reproduce frequencies up to 22.05KHz...
I disagree somewhat with the 'accurately' part for frequencies very close to or at the Nyquist limit. With about two samples per cycle, you can get anywhere from silence to somewhat accurate depending on the phase relationship between the ADC clock and the tone at 22.05kHz.
Also, there has to be enough room for the output filter to roll off from acceptably-close-to-zero attenuation at the highest audible frequency to acceptably-close-to-infinity attenuation at the Nyquist frequency. That's a no-man's land for audio content.
This is more like "Make" magazine savvy. Decoding the Mode-S transponder data sent on 1090 MHz would be a hell of a lot cooler, and would get all aircraft within range, not just the ones talking on a particular freq.
Slashdot Mirror
Wonder no more.
Maybe you should read up on fast reactors - a fast reactor is not necessarily also a breeder; a light water reactor breeds plutonium whether you want it to or not.
Also, the plutonium IFRs make is _less_ useful for weapons:
"... plutonium-bearing material taken from anywhere in the IFR cycle was so ornery, because of inherent heat, radioactivity and spontaneous neutrons, that making a bomb with it without chemical separation of the plutonium would be essentially impossible - far, far harder than using today's reactor-grade plutonium."
Don't try to scare people away by bringing up terms which you don't understand. A microwatt is a lot of power at these frequencies.
I definitely understand the terms and agree that -42dBm is a useful amount of power at 60GHz. Thanks for the ad hominem.
My point is that if you've got all that power and all that real estate to run such a large and terribly inefficient signal source, what does using it actually give you?
In any real-world comms application I can think of (outside the laboratory), spatial and temporal coherence are not needed and introduce more problems that they solve. The beamwidth is narrow but is still diffraction-limited; the same limit can easily be achieved with normal high gain antennas (at 30-70GHz, high gain antennas are tiny).
If for some reason you need temporal coherence, your only choices of modulation are by direct modulation of the pump laser; that is, mixing (heterodyning) the output of the maser with a modulating signal by conventional means (semiconductor mixer, for instance) would destroy the coherence. I suppose you could do the mixing in a non-linear waveguide setup, but that would be a lot of microwave plumbing. Similar results can be achieved using regular old polarized antennas without limiting your modulation choices.
In other words, using a maser for comms is a solution looking for a problem.
In your example, a 1 watt optical laser would be at best 45% efficient. So you're looking at about 2.2 Watts input for 63 uW out. A 20 GHz DRO followed by a doubler or tripler would give you significantly more output power per unit of input power, as well as be tunable and tiny. The DRO in the link consumes a maximum of 31.7 dBm of power and emits 13 dBm of RF. an IMPATT diode would be another good choice.
I agree completely (that's why I said "Good start"), but the wild, rabid enthusiasm of other commenters need to take that into account. They obviously didn't RFTA, so they hear 'maser' and thought it meant 'death ray'.
PS - I think you may have made it onto the DEA's watch list with your phrase "crystal he cooked up in a hurry". :-)
The new Mini? Made by BMW. In England.
That's funny - during the opening ceremony, while your country was extolling the virtues of your NHS to the world, the US broadcaster aired a commercial (advert) that described how some hospital in the UK desperately needed a bunch of hi-tech baby incubators and how GE donated them.
Why would that be, pray tell?
How about Mini Coopers? Mine was made in England.
I should have quoted this part of the article: "When configured as an oscillator, the solid-state maser’s measured output power of around 10 decibel milliwatts is approximately 100 million times greater than that of an atomic hydrogen maser, which oscillates at a similar frequency (about 1.42 gigahertz)." [emphasis mine].
I was not referring to it's gain as an amplifier; rather it's rather meager output as a 1.42 GHz oscillator. For 1.5 kW in, I'd expect at least half that much power out to be considered useful at all (that's for a solid-state or tube oscillator).
Here's a tunable VCO that uses 50mW to generate 2.5 mW from 1.277 to 1.691 GHz. That's 20:1.
The only use this thing has as an oscillator over other means are possibly frequency stability and coherence, neither of which are major concerns with regard to microwave transmission applications.
It may be 100 Million times as strong as its predecessor, but in absolute terms it required 1.5 KILOWATTS of input power to generate 100 MICROWATTS of output power. Not the most efficient thing in the world - that's an input:output power ratio of 15 million:1 (nearly 72 dB).
We see this in the length of antennas. To receive a signal, the antenna has to be at least a quarter wavelength. If you look at old cars that are made to receive conventional AM signals, they are longer.
Untrue. "conventional AM signals", at least in the US, are from 540kHz to 1610kHz. Wavelengths corresponding to those frequencies are 555.5m to 186m, respectively. Taking the shorter of the two, a quarter wavelength of 186m is 46.5m. I've never seen an antenna on a car that's 10x the length of the car! Any antenna, regardless of its length, can receive and frequency, it's just very inefficient to have antennas much, much shorter than the wavelength.
I think what you might mean is that for a monopole antenna to be resonant at a particular frequency, it must be an odd multiple of a quarter wavelength. Similarly, each of a dipoles's two arms must be an odd multiple of a quarter wavelength. You can add loading coils to physically-short antennas to make them resonant.
The "users" are the local population and their cattle who the army will eat and rape.
So the army will eat the local population and rape the cattle, or rape and eat them both?
The deer population explosion is so out of hand in Virginia they should issue machine guns for deer hunting.
Take a look at the deer hunting bag limits in Virginia. When I was a kid, the big question was "will it be one buck or two for the [two week] season?" The idea of shooting a doe was out of the question. Now it's more like "how many antlerless deer MUST I shoot before I can shoot a buck?" From the URL:
The bag limit for deer shall be two a day, six a license year. Of the six deer limit, no more than three may be antlered deer and at least three must be antlerless deer.
The season in Hanover is 100% antlered or antlerless, November 17 through January 5. In some localities you can 'Earn A Buck' by whacking does. In addition, you can get crop damage and other sorts of Bonus Deer Permits that permit you to exceed the season bag limit.
If my math is correct, there are 181 hunting days between all of the special seasons statewide. If I were infinitely wealthy and took advantage of every single day of legal hunting and bonus deer tags, I could take 2 deer a day for a total of 362 deer a season!
You clearly have no clue what you're talking about.
This rifle is but one example of the hundreds that have been manufactured in .308 Winchester for 60 years now. If you read the article, you'll see that the .308 cartridge was designed in 1952 AND IS THE BASIS FOR THE MILITARY CARTRIDGE. It is wildly popular in short-action rifles for hunting large game. It is typically loaded to slightly lower muzzle energies than the longer .30-06, but is usually cheaper, and as 'short' cartridge it allows for faster follow-up shots if needed. (It also is supposedly slightly more accurate because of its length).
Don't spout rhetoric; learn the facts.
Sorry, you have no no clue what you're talking about. First, get educated on the subject; read up on muzzle energy vs muzzle velocity. There are many sites about reloading that have that sort of data. Then go to a range and fire a few hundred rounds each in firearms chambered for many different rounds of varying calibers and muzzle energy, and get back to us that know what we're talking about from experience.
That is legal for deer hunting in all 50 states...
But not in Hanover County, Virginia. We must use shotguns (slugs ok) or muzzle-loaders. Strangely, Hanover is a mostly-rural county; surrounding heavily-populated counties like Henrico and the City of Richmond do not have similar restrictions. [I see that Chesterfield County has joined in on the rifle ban; too bad!]
If you're profoundly bored, Virginia hunting rules can be found here and a synopsis of local regulations can be found here.
You realize that:
1) Agent Orange was a 50:50 mixture of 2,4,5-T and 2,4-D
2) 2,4-D is still in widespread use today
3) It was the impurities in the 2,4,5,-T that caused the vast majority of the problems, not the 2,4,5-T, which, when properly manufactured, has relatively low toxicity.
Reminds me of one of my first network hub installations (yes, hubs). The only place to mount a stack of hubs was in the furnace room - an ancient oil-fired furnace that belched soot on every startup. To say the least the innards of those hubs were _disgusting_ in a very short while.
Social Security and Medicare must be massively reformed to be means based and not handouts to everyone over 65 (who are far far richer as a group than everyone under 30).
I once did the math, and found that it would be cheaper to cut a check for $30,000 to every single US family than continue spending all that money on the various 'entitlement' programs.
I'm not sure if it's available in all programming packages, but Dish Network currently carries NASA TV on channel 212. It will move on Aug 8th.
I agree with your comment, although it has nothing to do with my point - I disagreed with the OP's statement that "16 bit stereo at 44.1KHz can accurately reproduce frequencies up to 22.05KHz". I was not making any assertions with regard to the need to have content at those frequencies. In addition to the points I made earlier, if your so-called 'brick wall' filter isn't particularly good at eliminating (possibly spurious) content above the Nyquist limit, that content will fold back into the audible spectrum, adding to audible noise.
So you do mean Legion. Wikipedia says "Legio in Latin means Legion." I've always heard that Biblical quote in English, and it does use the word 'legion'.
The number of applications in everyday life are legio.
Is that LEGO or LEGION? Given a choice, I choose Lego(tm).
16 bit stereo at 44.1KHz can accurately reproduce frequencies up to 22.05KHz ...
I disagree somewhat with the 'accurately' part for frequencies very close to or at the Nyquist limit. With about two samples per cycle, you can get anywhere from silence to somewhat accurate depending on the phase relationship between the ADC clock and the tone at 22.05kHz.
Also, there has to be enough room for the output filter to roll off from acceptably-close-to-zero attenuation at the highest audible frequency to acceptably-close-to-infinity attenuation at the Nyquist frequency. That's a no-man's land for audio content.
This is more like "Make" magazine savvy. Decoding the Mode-S transponder data sent on 1090 MHz would be a hell of a lot cooler, and would get all aircraft within range, not just the ones talking on a particular freq.
Amateurs.
Wilford Brimley, is that you???