Cree has this page crowing about one of their their CXA series modules being 108 lm/W at 85c and 119 lm/W at 25c. I haven't found anything higher. Here's the datasheet.
GNU Radio makes the FPGA very dumb and feeds all the data over a long-delay pipe---ethernet/usb, host operating system, userland process---so it can't make swift decisions.
IIRC, the default firmware for the FPGA does a simple transform and pipes the I/Q samples over USB or ethernet. That is not to say that you couldn't put more of the functionality on the FPGA. I disagree that fiddling with FPGAs is "almost designing real radios, if you're implementing on FPGA". If you're processing the signal in the digital domain, it's still SDR, even though the 'S' is burned into an FPGA. 'Real Radios (tm)' require arcane analog/RF knowledge - things like filter design, mixer design, VCO design, etc - all the stuff that is frequency-dependent. SDR requires Hilbert transforms, Hamming windows, that sort of thing.
If I were trying to implement a specific protocol, I might test the algorithm out in GNU Radio, but I'd use a module like the Ettus SBX and put the radio logic in an FPGA or (very) fast CPU.
I'd heard of fractal antennas, of course, but I don't think they're widely available (other than LP's, as you mentioned). Here are some pics of the largest LP I've ever seen. I'll be seeing it again next week.:-)
That was your use case - for many other uses, YIGs are unneeded - a simple NCO/PLL will work just fine. There are plenty of A/D's that can sample more than 10 MHz at 16+ bits. For the 2.4 GHz use case you would not have to sample the RF signal directly - that would be silly. You would first downconvert the desired signal to a more reasonable IF (intermediate frequency) and then sample that. If you don't have image rejection requirements you could shift it to DC and sample that. Read up on superheterodyne receivers to start with, then digital up- and down-converters.
This company makes the Flex-6000 series Amateur transceivers - they are all digital and directly sample the HF and VHF bands from 30 kHz to 77 MHz continuously. This radio has every bell and whistle, and has incredible performance stats. It's expensive, but it is indicative of the amount of spectrum you can simultaneously sample.
From TFA: "Free-space path loss is proportional to the square of the distance between the transmitter and receiver, and also proportional to the square of the frequency of the radio signal." [Emphasis mine]
For the complete picture including antenna gain, etc, see Link Budget.
For the GP: 40 dBm EIRP is only 10W EIRP - That's 1 Watt into a 10 dBi antenna, 63 mW into your 22 dBi antenna, or 10 mW into a 30dBi antenna (or any combo of power levels/antenna gains that add up to 40 dBm). We're not talking "...several tens to several hundred Watts..." given that tens of dB gain antennas at 60 GHz are almost unavoidable.
You're welcome. Amateur radio folk have been on the forefront of DSP and SDR development for many years now. If you want to fool around with digital signal processing but don't want to invest in hardware, you can use the GNURadio package, along with the GNU Radio Companion to create DSP chains using an IDE and signals to/from your soundcard or arbitrary sound files.
For very little cash you can get a USB TV dongle that can be used as a signal source for GNU Radio. Search around a bit and you'll find sources - some are mentioned on the GNU Radio site.
If you're interested in doing DSP/SDR 'for real' over the air, consider getting a Technician-class Amateur radio license. You have all privileges above 30 MHz, and can do really nifty stuff. No Morse code required anymore - all theory and regs.
I wasn't commenting on the chaos that would ensue if these were widely available to every wannabe pirate radio hax0r or anarchist. I agree that would be a CB-esque mess. I was commenting on how hard it would be for 'Big Brother' to embed a hidden serial number in the transmitted waveform to track users for their own governmental nefarious purposes. Anyone with a pair of these could easily see the secret modulation.
most people who are likely to use this will be transmitting their call sign every time they broadcast. If by 'most people' you mean amateur radio operators, then I heartily agree (although we are not allowed to 'broadcast' in the common definition of the word).
If you have SDR equipment that can operate on 2.4GHz and has enough bandwidth, you could operate WiFi, ZigBee, and other protocols at the same time. You could have WiFi on channel 1, ZigBee on 11, etc. As long as the chipping codes don't collide, you can go nuts. As an example of relatively simple SDRs, check out these Web SDRs. These are single radios that digitize large swaths of spectrum. Each web user gets their own software virtual receiver that is tunable across the sampled spectrum. These radios can support hundreds of users at the same time, each listening to different freqs in different modes.
The radio hardware remains the same. The parts that can change are external to the actual 'radio' part - preselector filters, preamps, antennas, etc. Once you get the signal of interest to the radio, the processing is identical. Look around for descriptions of I/Q modulation - by supplying in-phase and quadrature signals, you can generate any modulation you want.
Who says they're not transmitting a serial number with each unit.
That would be very hard to hide from anyone with a even just a little test equipment. SDRs typically operate by taking user-generated in-phase and quadrature (I/Q) signals from the data source. These have the desired data waveform already encoded in them. Additional modulation (to sneak in a serial number) would appear as undesired spurs or noise.
Any that juice is full of sugars. Here in the US it seems that the mommy types think 'juice' is somehow good for their precious babies - they give it to them from morning to night and feel smugly good that they're giving their darlings the best things on Earth. Hardly! Those so-called juices are typically not 100% juice and are heavily sweetened. Even those that are 100% juice are still naturally high in sugars that will help drive type-II diabetes and possibly other conditions that are reaching epidemic proportions - ADHD, etc.
If a Cigarette company is slowly and most certainly killing you, then isnt it the Governments job to stop them? If the Alcohol companies are slowly and most certainly killing you, then isnt it the Governments job to stop them? If the Soda/Fastfood companies are slowly and most certainly killing you, then isnt it the Governments job to stop them?
Im not sure where you got the idea that Democracy dosent extend to telling you how to live your life when your being murdered by companies and driving up healthcare costs for the rest of us........
Perhaps in your authoritarian, liberal world you think it appropriate for the government to meddle in those areas of its victim's lives, but in my conservative world of personal responsibility, I most vehemently do not.
Did the Cigarette company force me to start smoking? No. Personal choice, personal responsibility. Did the Alcohol company force me to start drinking? No. Personal choice, personal responsibility. Did the Soda/Fast food company force me to start consuming their products? No. Personal choice, personal responsibility.
Do I expect you to pay my health care costs? Should my poor decisions make your costs go up? No! I pay for my own insurance, and I make my lifestyle choices.
It could've been that FB simply couldn't hear ground control. As an Amateur Radio operator, I was appalled at the horrible quality of the comms they were using. They couldn't hear each other half the time, and even at the best of times the transmissions were garbled beyond readability.
I think there was a point where he went to an in-suit radio (possibly before step 29), and comms went downhill fast.
The President has always had the right to directly command all agencies in the executive branch.
I didn't realize that ISPs and cell phone carriers were 'agencies of the executive branch', since this executive order, section 5.2 says the government can take over any/all 'privately-owned communications resources' as they see fit.
How about immigration law? This article seems to think the President overstepped his authority with this little gem signed by Napolitano.
The President only has four powers. Veto (which congress can bypass), appointment (which congress can reject), direct authority over the executive (which can be blocked by congressional oversight), and pardon (which has been effectively blocked by mass media).
You forgot executive orders, signing letters, the ability to start wars and not get congressional pre-approval or assent, and a whole host of other quasi-legal 'powers' the executive branch has given itself.
Quick quiz, what percentage of the US's reactors fall into this category?
Survey says...Quite nearly 100%. The only exceptions are test reactors, IIRC. Sadly, the so-called environmentalists have effectively prevented implementation of real Gen IV reactors that actually ARE failsafe.
Every* transformer has a primary fuse right beside it to help prevent overloads from causing the dreaded blown transformer. A fuse blowing is an inconvenience; a transformer actually overheating and 'blowing' is a life-threatening event. Fuses are cheap, lives are not.
*Where 'every' means all the pole-mounted ones I'm familiar with (central VA area). I'm sure there are exceptions pad-mounted transformers.
Generating electricity with existing RTG technology is about 5% efficient. This paper mentions phosphored white LEDs efficiencies at 55 Lm/W. This paper says "The efficiency of the color phosphors was experimentally compared within the range up to 90 Lm/W for green, up to 30 Lm/Watt for blue, and up to 35 Lm/Wt for red color at 14 kV." [In this case kV are keV since they were shooting electrons]. This site says the decay energy of a Gd-148 alpha particle is about 3.271 MeV.
Doing the math, 1 Gd-148 alpha decay is about 5.24E-13 Joules, so 1.9E+12 decays/sec would deliver 1 Watt.
Given an alpha particle power output of 1 Watt , converting it to electricity at 5% efficiency then running LEDs at 55Lm/W would result in 2.75 Lm of light. The same alpha flux directed on the phosphors would result in a minimum of 30 Lm in the blue part of the spectrum, 90 Lm in green, and 35 Lm in red.
This paper is one of my favorites - it states, "A ~0.2 kg block of pure Gd148 (~1 inch3) initially yields ~120 watts, sufficient in theory to meet the complete basal power needs of an entire human body for ~1 century...". That's an awful lot of power packed into a tiny 1 in^3 package!
Big blue flash of light(ning), huge explosion, smoke rising...
I hate to rain on your parade, but unless you were also drenched in burning transformer oil, what you likely experienced was a fuse blowing. They are designed to go off like a stick of dynamite so that the blades separate quickly to prevent arcing. I have seen fully-open fuses arc over 12 inches until it finally quenched.
What I meant to imply was "If all you want is light [and not electricity to run other things as well]...". There are plenty of phosphors out there that run the gamut from IR to UV. In fact it would be good to have a little UV to stimulate vitamin D production in the astronauts' skin.
If all you want is visible light, then an RTG is a horribly inefficient way to get it. As has been previously suggested, a full-blown fission reactor is a bit of a problem due to heat dumping and safety. Why not take the middle ground?
Use a powerful alpha-only emitter such as Gd-148 and a mix of phosphors to give you the spectrum and intensity you need. Alpha particles are stopped by almost anything, and as long as you don't inhale/ingest them, they're relatively harmless. Since you're talking a space environment and can generally trust the astronauts to not make too many errors in judgement, you could even use a beta emitter with a little shielding. We already have the phosphors to generate RGB, unless we've forgotten how to make them (think CRT - the electron gun is nothing more than an electronic beta emitter).
Slashdot Mirror
Cree has this page crowing about one of their their CXA series modules being 108 lm/W at 85c and 119 lm/W at 25c. I haven't found anything higher. Here's the datasheet.
GNU Radio makes the FPGA very dumb and feeds all the data over a long-delay pipe---ethernet/usb, host operating system, userland process---so it can't make swift decisions.
IIRC, the default firmware for the FPGA does a simple transform and pipes the I/Q samples over USB or ethernet. That is not to say that you couldn't put more of the functionality on the FPGA. I disagree that fiddling with FPGAs is "almost designing real radios, if you're implementing on FPGA". If you're processing the signal in the digital domain, it's still SDR, even though the 'S' is burned into an FPGA. 'Real Radios (tm)' require arcane analog/RF knowledge - things like filter design, mixer design, VCO design, etc - all the stuff that is frequency-dependent. SDR requires Hilbert transforms, Hamming windows, that sort of thing.
If I were trying to implement a specific protocol, I might test the algorithm out in GNU Radio, but I'd use a module like the Ettus SBX and put the radio logic in an FPGA or (very) fast CPU.
If the TSA were using radio waves you'd have a valid point of comparison. Sadly, you seem woefully ignorant of the topic...
Perhaps you're ignorant of the non-ionizing millimeter wave machines in use by the TSA?
X-rays are also radio waves (electromagnetic radiation), as are visible light, gamma rays, etc.
I'd heard of fractal antennas, of course, but I don't think they're widely available (other than LP's, as you mentioned). Here are some pics of the largest LP I've ever seen. I'll be seeing it again next week. :-)
That was your use case - for many other uses, YIGs are unneeded - a simple NCO/PLL will work just fine. There are plenty of A/D's that can sample more than 10 MHz at 16+ bits. For the 2.4 GHz use case you would not have to sample the RF signal directly - that would be silly. You would first downconvert the desired signal to a more reasonable IF (intermediate frequency) and then sample that. If you don't have image rejection requirements you could shift it to DC and sample that. Read up on superheterodyne receivers to start with, then digital up- and down-converters.
This company makes the Flex-6000 series Amateur transceivers - they are all digital and directly sample the HF and VHF bands from 30 kHz to 77 MHz continuously. This radio has every bell and whistle, and has incredible performance stats. It's expensive, but it is indicative of the amount of spectrum you can simultaneously sample.
Please study up on free space path loss.
From TFA: "Free-space path loss is proportional to the square of the distance between the transmitter and receiver, and also proportional to the square of the frequency of the radio signal." [Emphasis mine]
For the complete picture including antenna gain, etc, see Link Budget.
For the GP: 40 dBm EIRP is only 10W EIRP - That's 1 Watt into a 10 dBi antenna, 63 mW into your 22 dBi antenna, or 10 mW into a 30dBi antenna (or any combo of power levels/antenna gains that add up to 40 dBm). We're not talking "...several tens to several hundred Watts..." given that tens of dB gain antennas at 60 GHz are almost unavoidable.
You're welcome. Amateur radio folk have been on the forefront of DSP and SDR development for many years now. If you want to fool around with digital signal processing but don't want to invest in hardware, you can use the GNURadio package, along with the GNU Radio Companion to create DSP chains using an IDE and signals to/from your soundcard or arbitrary sound files.
For very little cash you can get a USB TV dongle that can be used as a signal source for GNU Radio. Search around a bit and you'll find sources - some are mentioned on the GNU Radio site.
If you're interested in doing DSP/SDR 'for real' over the air, consider getting a Technician-class Amateur radio license. You have all privileges above 30 MHz, and can do really nifty stuff. No Morse code required anymore - all theory and regs.
I wasn't commenting on the chaos that would ensue if these were widely available to every wannabe pirate radio hax0r or anarchist. I agree that would be a CB-esque mess. I was commenting on how hard it would be for 'Big Brother' to embed a hidden serial number in the transmitted waveform to track users for their own governmental nefarious purposes. Anyone with a pair of these could easily see the secret modulation.
most people who are likely to use this will be transmitting their call sign every time they broadcast.
If by 'most people' you mean amateur radio operators, then I heartily agree (although we are not allowed to 'broadcast' in the common definition of the word).
If you have SDR equipment that can operate on 2.4GHz and has enough bandwidth, you could operate WiFi, ZigBee, and other protocols at the same time. You could have WiFi on channel 1, ZigBee on 11, etc. As long as the chipping codes don't collide, you can go nuts. As an example of relatively simple SDRs, check out these Web SDRs. These are single radios that digitize large swaths of spectrum. Each web user gets their own software virtual receiver that is tunable across the sampled spectrum. These radios can support hundreds of users at the same time, each listening to different freqs in different modes.
The radio hardware remains the same. The parts that can change are external to the actual 'radio' part - preselector filters, preamps, antennas, etc. Once you get the signal of interest to the radio, the processing is identical. Look around for descriptions of I/Q modulation - by supplying in-phase and quadrature signals, you can generate any modulation you want.
Who says they're not transmitting a serial number with each unit.
That would be very hard to hide from anyone with a even just a little test equipment. SDRs typically operate by taking user-generated in-phase and quadrature (I/Q) signals from the data source. These have the desired data waveform already encoded in them. Additional modulation (to sneak in a serial number) would appear as undesired spurs or noise.
Log periodic or discone.
In my world we still drink ... juice ...
Any that juice is full of sugars. Here in the US it seems that the mommy types think 'juice' is somehow good for their precious babies - they give it to them from morning to night and feel smugly good that they're giving their darlings the best things on Earth. Hardly! Those so-called juices are typically not 100% juice and are heavily sweetened. Even those that are 100% juice are still naturally high in sugars that will help drive type-II diabetes and possibly other conditions that are reaching epidemic proportions - ADHD, etc.
If a Cigarette company is slowly and most certainly killing you, then isnt it the Governments job to stop them?
If the Alcohol companies are slowly and most certainly killing you, then isnt it the Governments job to stop them?
If the Soda/Fastfood companies are slowly and most certainly killing you, then isnt it the Governments job to stop them?
Im not sure where you got the idea that Democracy dosent extend to telling you how to live your life when your being murdered by companies and driving up healthcare costs for the rest of us........
Perhaps in your authoritarian, liberal world you think it appropriate for the government to meddle in those areas of its victim's lives, but in my conservative world of personal responsibility, I most vehemently do not.
Did the Cigarette company force me to start smoking? No. Personal choice, personal responsibility.
Did the Alcohol company force me to start drinking? No. Personal choice, personal responsibility.
Did the Soda/Fast food company force me to start consuming their products? No. Personal choice, personal responsibility.
Do I expect you to pay my health care costs? Should my poor decisions make your costs go up? No! I pay for my own insurance, and I make my lifestyle choices.
1024, of course.
The Russian GLONASS system has satellites in inclined orbits at 64.8 degrees...
That inclination reminded me of the strange-but-useful Molniya Orbit. At least three Amateur radio Satellites were launched into this type of orbit.
(The Glonass orbit is very nearly circular and the Molniya is very ellipitical).
It could've been that FB simply couldn't hear ground control. As an Amateur Radio operator, I was appalled at the horrible quality of the comms they were using. They couldn't hear each other half the time, and even at the best of times the transmissions were garbled beyond readability.
I think there was a point where he went to an in-suit radio (possibly before step 29), and comms went downhill fast.
The President has always had the right to directly command all agencies in the executive branch.
I didn't realize that ISPs and cell phone carriers were 'agencies of the executive branch', since this executive order, section 5.2 says the government can take over any/all 'privately-owned communications resources' as they see fit.
How about immigration law? This article seems to think the President overstepped his authority with this little gem signed by Napolitano.
The President only has four powers. Veto (which congress can bypass), appointment (which congress can reject), direct authority over the executive (which can be blocked by congressional oversight), and pardon (which has been effectively blocked by mass media).
You forgot executive orders, signing letters, the ability to start wars and not get congressional pre-approval or assent, and a whole host of other quasi-legal 'powers' the executive branch has given itself.
Quick quiz, what percentage of the US's reactors fall into this category?
Survey says...Quite nearly 100%. The only exceptions are test reactors, IIRC. Sadly, the so-called environmentalists have effectively prevented implementation of real Gen IV reactors that actually ARE failsafe.
Your potassium iodide is radioactive! It emits anti-matter and neutrinos and gamma rays and 'lectrons! Run Away! <sarcasm/>
In case you think I'm kidding, look it up. That 130mg pill undergoes a little more than 1.2 decays/sec.
Every* transformer has a primary fuse right beside it to help prevent overloads from causing the dreaded blown transformer. A fuse blowing is an inconvenience; a transformer actually overheating and 'blowing' is a life-threatening event. Fuses are cheap, lives are not.
*Where 'every' means all the pole-mounted ones I'm familiar with (central VA area). I'm sure there are exceptions pad-mounted transformers.
Generating electricity with existing RTG technology is about 5% efficient. This paper mentions phosphored white LEDs efficiencies at 55 Lm/W. This paper says "The efficiency of the color phosphors was experimentally compared within the range up to 90 Lm/W for green, up to 30 Lm/Watt for blue, and up to 35 Lm/Wt for red color at 14 kV." [In this case kV are keV since they were shooting electrons]. This site says the decay energy of a Gd-148 alpha particle is about 3.271 MeV.
Doing the math, 1 Gd-148 alpha decay is about 5.24E-13 Joules, so 1.9E+12 decays/sec would deliver 1 Watt.
Given an alpha particle power output of 1 Watt , converting it to electricity at 5% efficiency then running LEDs at 55Lm/W would result in 2.75 Lm of light. The same alpha flux directed on the phosphors would result in a minimum of 30 Lm in the blue part of the spectrum, 90 Lm in green, and 35 Lm in red.
This paper is one of my favorites - it states, "A ~0.2 kg block of pure Gd148 (~1 inch3) initially yields ~120 watts, sufficient in theory to meet the complete basal power needs of an entire human body for ~1 century...". That's an awful lot of power packed into a tiny 1 in^3 package!
Fascinating stuff.
Big blue flash of light(ning), huge explosion, smoke rising...
I hate to rain on your parade, but unless you were also drenched in burning transformer oil, what you likely experienced was a fuse blowing. They are designed to go off like a stick of dynamite so that the blades separate quickly to prevent arcing. I have seen fully-open fuses arc over 12 inches until it finally quenched.
Example video
What I meant to imply was "If all you want is light [and not electricity to run other things as well] ...". There are plenty of phosphors out there that run the gamut from IR to UV. In fact it would be good to have a little UV to stimulate vitamin D production in the astronauts' skin.
If all you want is visible light, then an RTG is a horribly inefficient way to get it. As has been previously suggested, a full-blown fission reactor is a bit of a problem due to heat dumping and safety. Why not take the middle ground?
Use a powerful alpha-only emitter such as Gd-148 and a mix of phosphors to give you the spectrum and intensity you need. Alpha particles are stopped by almost anything, and as long as you don't inhale/ingest them, they're relatively harmless. Since you're talking a space environment and can generally trust the astronauts to not make too many errors in judgement, you could even use a beta emitter with a little shielding. We already have the phosphors to generate RGB, unless we've forgotten how to make them (think CRT - the electron gun is nothing more than an electronic beta emitter).