Get Ready For Atomic Radio (technologyreview.com) 125
An anonymous reader quotes a report from MIT Technology Review: David Anderson at Rydberg Technologies in Ann Arbor, Michigan, and a couple of colleagues, have reinvented the antenna from scratch. Their new device works in an entirely different way from conventional antennas, using a laser to measure the way radio signals interact with certain types of atoms. The secret sauce in the new device is Rydberg atoms. These are cesium atoms in which the outer electrons are so excited that they orbit the nucleus at great distance. At these distances, the electrons' potential energy levels are extremely closely spaced, and this gives them special properties. Indeed, any small electric field can nudge them from one level to another. Radio waves consist of alternating electric fields that readily interact with any Rydberg atoms they come across. This makes them potential sensors.
But how to detect this interaction? A gas made of Rydberg atoms has another property that turns out to be useful -- it can be made transparent by a laser tuned to a specific frequency. This laser essentially saturates the gas's ability to absorb light, allowing another laser beam to pass through it. However, the critical frequency at which this happens depends crucially on the properties of the Rydberg atoms in the gas. When these atoms interact with radio waves, the critical frequency changes in response. That's the basis of the radio detection. Anderson and co create a gas of cesium atoms excited into Rydberg states. They then use a laser tuned to a specific frequency to make the gas transparent. Finally, they shine a second laser through the gas and measure how much light is absorbed, to see how the transparency varies with ambient radio waves. The signal from a simple light-sensitive photodiode then reveals the way the radio signals are frequency modulated or amplitude modulated. The atomic radio can detect a huge range of signals -- over four octaves from the C band to the Q band, or wavelengths from 2.5 to 15 centimeters. It also should be less insensitive to electromagnetic interference due to its lack of conventional radio circuitry. "The atomic radio wave receiver operates by direct real-time optical detection of the atomic response to AM and FM baseband signals, precluding the need for traditional de-modulation and signal-conditioning electronics," say Anderson and co.
But how to detect this interaction? A gas made of Rydberg atoms has another property that turns out to be useful -- it can be made transparent by a laser tuned to a specific frequency. This laser essentially saturates the gas's ability to absorb light, allowing another laser beam to pass through it. However, the critical frequency at which this happens depends crucially on the properties of the Rydberg atoms in the gas. When these atoms interact with radio waves, the critical frequency changes in response. That's the basis of the radio detection. Anderson and co create a gas of cesium atoms excited into Rydberg states. They then use a laser tuned to a specific frequency to make the gas transparent. Finally, they shine a second laser through the gas and measure how much light is absorbed, to see how the transparency varies with ambient radio waves. The signal from a simple light-sensitive photodiode then reveals the way the radio signals are frequency modulated or amplitude modulated. The atomic radio can detect a huge range of signals -- over four octaves from the C band to the Q band, or wavelengths from 2.5 to 15 centimeters. It also should be less insensitive to electromagnetic interference due to its lack of conventional radio circuitry. "The atomic radio wave receiver operates by direct real-time optical detection of the atomic response to AM and FM baseband signals, precluding the need for traditional de-modulation and signal-conditioning electronics," say Anderson and co.
‘Less Insensitive’ (Score:1)
Huh?
Great moments in summarization... (Score:4, Interesting)
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I came here to point out A Mistake on the Internet, and was pleased to get a double dose! I'm glad /. doesn't allow edits :)
Re:Great moments in summarization... (Score:4, Informative)
I interpreted it as "less sensitive" which would be correct.
There are lots of different kinds of interference. In a good radio system, noise from the radio's electronics should be a minor component, dominated by thermal noise, to say nothing of "interference" which is other legitimate radio waves that just happen to not be of interest to the operator. This system would probably have less electronic noise, but could easily have worse thermal noise.
Re:Only requires (Score:5, Interesting)
highly radioactive
No.
Highly REactive: Add water and it burns. Not an issue when it's a trace of gas in, say, a "gassy vacuum tube" the size of a grain of rice.
The isotope you mine is the (only) stable one. You can get radioactive isotopes from reactor waste - but you can get radioactive isotopes of just about ANY element from reactor waste.
Lasers are often small diodes these days. Shining two through a glass capsule - then into an absorber in one case and a photodetector in the other - is no big deal.
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"Your MOM goestocollege"
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this was something I was curious about: how large is this setup presently, and small do they think they can make it. The article mentions they had the excited cesium in a vapor cell. Vapor cells [google.com] are lab-grade blown glassware, one-to-several cm in diameter and at least several cm long. That isn't going to replace the antennae in my smartphone anytime soon.
On the other hand, this is an experimental setup, probably spanning a large tabletop (an optical ta
Re:Only requires (Score:5, Funny)
What's the benefit? (Score:1)
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basically you use laser 1 to make the gas "sensitive" to a very specific frequency. then you use a second laser with an optical sensor to identify the minute differences which can be demodulated into audio or digital signals, or whatever is useful.
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Why is this better than current radio?
Reading TFA, it isn't better. So we're going to replace a compact radio with a tube of cesium and lasers? This is exceptionally interesting, but trying to see the practicality of it is a non-starter.
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An antenna the size of a grain of rice versus being measured in feet and you don't see the practicality?
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With high bandwidths, such as will be used for 5G, you are into the sweet spot for this technology.
In other words, this has potential.
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But it's receive only, not really useful for a communication device.
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Good point. However, receive and transmit antennae are normally separate anyway. You use a multi-element receive antenna, but a single element transmit antenna. If you can replace all of your multi-element receive antennae with a single, smaller one, that's still a big win in terms of tower real-estate.
Actually... This is not true. The same antenna is used for receive and transmit all the time. You have both full duplex (RX and TX at the same time) and half Duplex applications that do this.
Your local cell tower and cell phone is a perfect example of this. My local Ham radio repeater does full duplex every time it's keyed.
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Good point. However, receive and transmit antennae are normally separate anyway. You use a multi-element receive antenna, but a single element transmit antenna. If you can replace all of your multi-element receive antennae with a single, smaller one, that's still a big win in terms of tower real-estate.
Could you show me an implementation of what you consider a normal antenna array?
I'll bounce that off of a friend who owns a communication company. None of his sites are normal it would appear, so he apparently need some expert help.
Why oh why would you ever want to use an antenna of only one element while you had a nice gain antenna on the same frequency? If you are using the directivity the multi element provides, you will be hearing signals that the monopole might not have enough power to get back
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But it's receive only, not really useful for a communication device.
But great potential for radioastronomy.
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Yeah, but the antennas are so tiny that it doesn't really matter.
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The size of an antenna is determined by the wavelength being received or transmitted. It's far from clear how this technology changes that.
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One antenna covering a huge range of frequencies, rather than many. As the article says, a normal antenna is one or more conductors, each 1/2 wavelength long.
Actually, their dipole is two opposed elements that are a quarter wavelength each element, but that's a drastic simplification.
If you have many bands, such as the cellphone system, then you need one antenna for each band.
With high bandwidths, such as will be used for 5G, you are into the sweet spot for this technology.
In other words, this has potential.
For the purpose of simplification, let's assume that you want to make a dipole at 1 GHz. The total wavelength at that frequency is roughly 300 mm. So a dipole antenna would be around 150 mm each leg.
Now with the antennas being so small, we often add gain to them by making a Yagi-Uda antenna. This has a driven element, an element behind it, and usually one or more elements in fro
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You don't need a high-gain antenna, if instead you can amplify a weak signal and not introduce noise.
That certainly would be nice. The problem with weak signals is that they come with the noise attached. We do have innovative ways of receiving data that is actually at or below the noise floor. It is very slow, however. But this is a miraculous antenna indeed if it discards all of the noise, and amplies only the signal that you want.
An ordinary antenna senses EM waves by turning them into electricity directly. Well understood, and with well-known limitations like antenna sizes.
This thing has a medium whose transparency varies with the EM waves passing through it. Transparency is then measured by passing light through it. The signal is then available as variable light, instead of electricity.
You do understand that light is still electromagnetic energy don't you? https://en.wikipedia.org/wiki/... [wikipedia.org]. This is along the same path as the visible light transmitters and re
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yeah, let's all judge the potential of new tech by its first clunky prototype.
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yeah, let's all judge the potential of new tech by its first clunky prototype.
Every few years, there is some "major breakthrough" in antennas. Almost all turn out to be major fails. I remember the Rutgers antenna that they claimed the prototype was so efficient that it melted when they pumped 100 watts through it! They actually said that, despite the fct that converting RF energy into heat was the exact opposite of efficiency. Then there was the Italian circularly polarized dish antenna that supposedly did it's polarization by virtue of putting a spiral shape on the dish. Then there
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Lasers aren't that clunky, they are nice & small these days. Every blu-ray player has 3 or so - small compared to the clunky rotating medium.
Radio to optic signal instead of electric is interesting. Even more interesting if it picks up weaker signals than the ordinary approach.
Even more interesting is it it will brew me a cup of coffee in the morning.
Look, if this will allow below the noise floor instantaneous communications with zero noise and always perfect reception, it will be a lot more than a use of a known concept. It will require a total re-write of the laws of physics. And I'll be happy to be wrong.
If you are so certain, hold your breath until this optical antenna eliminates all other towers - they won't be needed any more because of the elimination of the signal t
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Clearly we should stop trying because we have already invented the best of everything that can be invented.
Clearly you have slippery sloped this to the max.
Pointing out issues is how science works. The science of this is fascinating. But your approach is the exact opposite of what is needed. Skepticism is the rule to progress.
This is how people who are denialisms of AGW and Creationists accidentally help undermine their own faith. Pointing out anything that remotely looks anomalous, and the scientists scurry to address that issue.
Anyone who simply says "Oh this is freaking awesome and the way of the futu
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Why does this have a score of 2? People must be self modifying. Any extreme reception problem now may have a better solution, such as: Submarine to surface communications, satellite to surface, radio space exploration, etc.. Not all radio communications are consumer. I can't believe that the military hasn't classified this and started creating better communications equipment, etc.
Because it isn't better. Just because people do experiments and get all excited about them does not ipso facto make the thing they are all excited about the ultimate. It is merely a receive antenna that is made by utilizing a pretty standard physics application. It isn't really anything new, and not having the ability to transmit, and with the basic physics not showing any practical way to get any gain out of the antennas, then it is relegated to interesting footnote status. A interesting solution that is
Re:What's the benefit? (Score:5, Interesting)
Why is this better than current radio?
Replace an antenna the size of your hand, your arm, rabbit ears, a tower, ... with something you can mount on a chip in a tiny package on a PC board.
Get rid of the noise, intermodulation, and other pathologies in the high gain amplification and filtering of the tiny amount of energy picked up by that antenna, substituting a direct quantum-mechanical readout of the field, with high signal strength, only competing with noise from variations in the lasers' output as your starting point, feeding a strong signal to a more ordinary amplifier.
If it works out it could be a big deal in a tiny package.
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Its not clear from the article what the effective collection area or noise temperature is for this. Its possible that it works with laser cooled atoms to provide an extremely low noise receiver that could be useful for scientific applications.
That said, they seem to be measuring ~6V/M field levels, which is far larger than the signals received by conventional radios. (usually micro-volts/meter), so its not clear what they would do to improve the power sensitivity by ~12 orders of magnitude.
Still, its sort o
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It's got one minor drawback.
It can only receive signals.
Good for broadcast, not so good for anything requiring two way communication, like pretty much everything except TV and radio.
Re:What's the benefit? (Score:5, Interesting)
It can only receive signals.
Good for broadcast, not so good for anything requiring two way communication,
Transmitting with a tiny antenna is easy. You use the same amount of energy as with a big antenna, but with a little antenna the energy density is much higher. As long as you make the impedance match properly, so all the energy is launched, you're fine, regardless of the area of the antenna.
One antenna I'm working with currently is for BLE - on the 2.4G band. The quarter-wavelength there is about 1 1/4 ". But the antenna is mostly a chip of ceramic, with some horrendously high permittivity. (Ceramics can get to 6k or so, though I haven't computed the scale of this thing to estimate its permittivity.) So the quarter-wavelength, in and immediately around the chip, is scaled down in proportion, making the antenna about the same length as a surface-mount capacitor, though substantially narrower. The energy density is also scaled up (in proportion squared), and by the time the wave has expanded to the size of a free-air quarter-wavelength antenna the energy density is down to just that of the larger antenna.
On the receiving side it still works - sort of. But the energy density of the incoming wave doesn't scale up at all when the antenna shrinks. So it intercepts only the tiny amount of energy that passes within a scaled-down quarter-wavelength around the scaled-down antenna, rather than that passing withing a free-air quarter wavelength of a free-air quarter wavelength metallic conductor.
So one of these for transmitting and one of the invention for receiving (if it also works at such a tiny size) and you have your ultraminiaturized two-way system.
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GPS/Glonass/Galileo receivers would be another one.
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Which part of description makes you think its "tiny".
The part where the antenna element is an individual atom, rather than a quarter-wavelength of metal or other conductor, and you only need enough of them to measurably occlude - or scatter - a laser beam, which can be quite narrow. If you can get enough of them into the requisite set of states to perform your measurements in a path length substantially less than a quarter wavelength of the frequency in question, you've got your miniaturiation.
Granted the
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If it works out it could be a big deal in a tiny package.
Especially for radar.
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It's not that it's "better" but a completely new method of detecting radio waves. Radio receivers haven't really changed all that much since the invention of the transistor, mostly it's been miniaturization more than anything.
This receiver would fall under the category of basic research, not a practical receiver.
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Amazing advance (Score:1)
I mean really that's about the equivalent of turning an electron gas into your antenna. Still will need signal conditioning and demodulation though unless it's very linear.
Huh? (Score:5, Interesting)
reinvented the antenna from scratch
The battery was reinvented, due to it's first development, in what is now modern day Iran, being lost over time. The antenna, however, has not been forgotten so could not have been "reinvented". Redesigned, perhaps, or a new type of antenna may have been invented, but the antenna on my roof is still there, and is still a variation of the first dipole antenna invented by Heinrich Hertz. This seems to be a variation of the phased array, just on a molecular scale, who's development has been filtered through the marketing department.
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Why do you hate innovation from the innovating innovators? Is it because you are afraid of change?
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reinvented the antenna from scratch
The battery was reinvented, due to it's first development, in what is now modern day Iran, being lost over time. The antenna, however, has not been forgotten so could not have been "reinvented". Redesigned, perhaps, or a new type of antenna may have been invented, but the antenna on my roof is still there, and is still a variation of the first dipole antenna invented by Heinrich Hertz. This seems to be a variation of the phased array, just on a molecular scale, who's development has been filtered through the marketing department.
It's become a fairly common usage now.
If someone is said to have "reinvented" the sitcom, it doesn't mean (despite evidence to the contrary, badum ching) that we have forgotten how to make sitcoms. It means that someone has come up with a radical new version of the type.
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reinvent [oxforddictionaries.com]: "Change (something) so much that it appears to be entirely new."
The antenna could very well have been reinvented, so long as one's ego is small enough to realize that they are not the sole arbiter of the meaning of common words
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reinvent [oxforddictionaries.com]: "Change (something) so much that it appears to be entirely new."
If you change something so much that it appears to be an entirely new thing, it IS an entirely new thing.
FTFS: "Their new device works in an entirely different way from conventional antennas, using a laser to measure the way radio signals interact with certain types of atoms."
The invention of the LCD panel didn't reinvent the display tube, it replaced it with an entirely different method, which just happened to provide the same function. Same thing here. Using cesium atoms in a container, excited by two lasers, they were able to detect radio waves by the change in frequency of the atoms in that gas. That, by the way, was where I was getting the phased array analogy from.
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Again, you do not determine what words mean. The community determines what words mean. What has been done fits within the commonly accepted meaning of the term "reinvented," ergo you cannot properly say that "the antenna could not have been 'reinvented.'"
But it did reinvent the electronic display.
Finally... (Score:5, Insightful)
Missed a geek naming opportunity (Score:3)
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If only Futurama was invented 100 years ago when they figured that shit out.
Not a new form of radio. (Score:4, Informative)
It's not a new form of radio, it is a new form of radio receiver.
In other words (Score:1)
Forgive me for preferring my CDs and USB device over your "radio".
This is a big wow (Score:2)
Read the article a few times. This is pretty amazing stuff. Truly ingenious way of looking at the task
Does it go the other way as well? (Score:2)
The bottleneck for two-way communication is generally the return channel of the mobile device. Is this going to help with efficiency at that end, or is this inherently a one-way process? It would seem to me that the process inherently includes an opto-isolator, which makes the process irreversible. It will still help by pushing the noise floor down on the receive end, but if we're still stuck with the same old transmit antennas we have now, this design isn't going to make phones any smaller since it can't r
Re:Does it go the other way as well? (Score:5, Insightful)
You can make the transmitting antenna very small compared to the receiving antenna.
An analogy would be spraying water from a hose (transmitting) where the diameter can very small and the water exits at a much higher speed (energy density). To receive the water in useful quantities you can't use a funnel with the same size as the hose, instead you need to scale the funnel up many magnitudes (size dependent on the distance between the hose and the funnel)..
The atomic receiver in this scenario is equivalent to a funnel that's actually smaller than the hose regardless of the distance between the two.
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The hose and the funnel works in the same way, they are equally inefficient for transmit and receive given the same size. As soon as the distance increase you get an increased loss, exactly the same as with electrical antennas.
The ratio of loss vs distance is of course not the same due to the different physics involved but if you purely look on the signal strength from a receiving antenna size matters, exactly as with the amount of water a larger funnel can catch.
a couple of points (Score:1)
very cool idea.
nowhere even remotely as good as a modern receiver IC.
but very cool idea.
Cool! (Score:2)
I think I just had a StarTrek moment here. The concept is simple and elegant (obviously practical aspects aren't quite as simple but certainly far from undoable) A combination of shit we already knew and already had to do something nobody thought of yet.
I may be in love here to a degree that I wont even ask for when we can expect this to be commercially available ;).
Chris Moyles (Score:1)
Phased arrays and directionality (Score:2)
What gets me most excited about this is that the receiving element is tiny- if they can also be made dense- and it looks like there are elements that can be shared among multiple receivers to increase density. A dense set of antennas allows for very directional beamforming, and IIRC, this is a sufficient way to have an extremely accurate directional receiver. The Coherence of the laser should even help with that. Their photodiode as a demodulator is primitive, but a start.
Invention of a century (Score:2)
It's truly a remarkable invention, everything relies on wireless transmission nowadays. From this brief description it suggests that this new antenna is not only very wide band but also very sensitive (not to mention the size). I hope it will get into market soon, it will revolutionize communication not only on Earth but also between satellites. I also wonder an impact on radio astronomy, instead of huge heavy collector dishes one might imagine a field of these sensors (depending on its price and sensitivi
the questions everyone really wants to know (Score:2)
What is the sensitivity and latency using this method? Since it occurs at the atomic scale can we assume that the chance of getting real data throughput in the FM band quite good?
What will be the impact on transmission power requirements given this heightened sensitivity? Will low power devices be as clear-reception as the type of power transmission hitting the airwaves when you tune into a radio station?
The biggest downfall to 2.4ghz and 5.8ghz (aside from crowding and cross-talk interference) is the line
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How did this get from C to Q band to AM/FM? Quite a leap, not mere octaves.
Or do I have to wade through this to see that antenna tech that can span in one device from 55,000 to 2.5 cm?
Yeah, that is impressive. Now to hook this into a SDR and have some real fun, if it's smaller than a camper.
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FM is a huge range actually, covering more than just public broadcast. But the article did mention both.
"The atomic radio wave receiver operates by direct real-time optical detection of the atomic response to AM and FM baseband signals, precluding the need for traditional de-modulation and signal-conditioning electronics,"
right now detection is limited to wavelengths from 2.5 to 15 centimeters ... which is 2Ghz - 10Ghz, definitely much higher than the 88 - 108 Mhz frequencies reserved for public radio broa
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AM and FM are modulations, used in broadcast band communications. This technique (as described by the paper) can be used to play back signals that were modulated onto a carrier- changing the carrier's Amplitude and Frequency.
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I understood that. More interesting was the assertion that this technology would be useful from 550m to 2.5cm. Or perhaps even broader application, it seems going from AM broadcast band to LW wouldn't be a big leap if you're going from upper microwave..
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OK, Gotcha. As I understand it, more than anything, what the paper shows is a proof-of-concept that does away with traditional antennas (using electromagnetic waves to induce electron flow in a conductor), replacing it with monitoring something that is changing due to EM waves effect upon quantum states- making the wavelength of the electromagnetic wave irrelevant. Of course, this is my interpretation, but if it proves out- this is a very different way of doing things than we have been doing since Maxwell,
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the potential upside is that you dont have to get brain cancer by transmitting from your cell phone in order to be picked up by the tower. Lower transmission power should be able to be 'heard' using this technology. This directly translates to better signal quality, less interference, and lower battery consumption. The LTE antenna is the biggest battery drain on your phone right after the active display. Along side these is the wi-fi antenna on your phone. So the upsides are:
better coverage and lower power
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Yes, it is useful for mobile phones (Score:2)
Complicated (Score:1)
What a f***cking complicated way to listen to your favorite FM station.
Re:Too little too late (Score:5, Insightful)
Nobody has cared about radio for 15 years. Inventing a new form of radio is interesting but pointless.
So you don't use a smartphone or a wireless router, or any form of wireless transmission? You don't care because radio is everywhere.
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Pssst! Don't tell anyone, but Radio is code word for "conservative talk radio". Only conservatives spies get there marching orders from Rush Limbaugh. At any moment, they're ready to act on a coordinated attack against gays and hipsters. A Pearl Harbor event were they take San Francisco.
Radio, ATOMIC Radio... be afraid! Be very very afraid for now the voices are to be heard much clearer now.
You know - I think you're right about what a lot of people think. They hear the word radio, and they think of the dying AM radio world.
I remember when Hams with their Handi-talkies were looked upon as nerds. Now people are hopelessly addicted to their smartphones, but they are somehow cool. Either way, those little devices are two way radios.
I'm at breakfast now, connected to the restaurant's router with the radio in my laptop. Looking at the local mountains with all of their towers.
For all of the
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the next fallout will perhaps include even more atomic radio
If we do ever decide it's time to play with our nucs, radio communications will be pretty dicey for quite a while. Those EMP pulses are going to shut down a lot of communications. Might be some Ionosphere disruptions as well.
A lot of Emergency communicators store their equipment in Faraday cages for just that reason. I have some radios stored in ammo boxes to protect against EMP. A direct strike obviously won't matter as we turning into overcooked toast or die of radiation poisoning.
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