No, but developing one SDR that works for all phones in 50 countries without worrying about patent infringement certainly sounds like a good way of getting a high ROI when investing in a new technology. Of course there's a lot of work and expense, but I think SDRs are still a great way to go, especially since the best ones now (unlike even 2 years ago) perform almost as well as hardware-defined radios.

I grant that it's always possible to do at least a little better when you know the frequencies you'll use at design time than if you have to have a software defined radio.

That said, Caroline Andrews of the lab I worked in (http://molnargroup.ece.cornell.edu/research.html) developed a software-defined radio using a passive mixer that works in the GHz range with only 1 dB worse noise for the same power as you would use with a fixed radio. She also showed how a software defined radio can do impedance matching through the passive mixer. Amazing, possibly game-changing stuff; if you really are a cellphone radio engineer, don't assume that software-defined radios will always suck hard enough not to be a threat.

By the way, on behalf of Slashdot, YOU'RE WELCOME FOR TEACHING YOU HOW TO DESIGN A PHONE!

Not necessarily. This lab from Cornell isn't going to patent their SDR, and it's a pretty sweet implementation: noise performance almost as good and chip area only slightly larger than a single-band ASIC:

http://molnargroup.ece.cornell.edu/research.html

Full disclosure: I worked with these guys, and the radio group is pure genius.

Does it really matter where they're made? The companies that own the intellectual property are the ones making most of the profit. If a company in China charged enough to make a killing on manufacturing, the owners could look to another company to fill the orders instead. Need proof that this actually happens? Look at how Vietnam is stealing manufacturing jobs from China.

China gets a bad rap, and they might deserve it due to poor labor practices, environmental standards and safety policy. Complain about those issues - I'll likely join you. They don't however deserve to be vilified because they're bleeding us dry with their over-priced manufacturing costs - that betrays a fundamental misunderstanding of the free market. If anything, having a place where manufacturing can be done cheaply is actually a good thing.

Case in point: I'm considering starting to manufacture a niche electronics gizmo for neuroscientists. Using a Chinese company to manufacture most of the hardware (but keeping the final steps in-house to maintain secrecy and avoid the possibility of clones appearing) I should be able to get my first revenue after only a $6,000 investment. My gross profit margin will be 400% - the Chinese are working hard for their tiny 20% share of the pie, and I don't begrudge them their pittance, since neither half of this "partnership" would be viable without the other.

"A few hackers, in their spare time, with no documentation about the hardware, and without the software keys theoretically required to obtain full access to it, managed to do what the multinational corporation that designed the phone said was impossible to do. "

Point taken. However, you might be surprised at how little resourcefulness can be found in multinational corporations. The best talent doesn't always find its way there, and sometimes a small number of brilliant individuals can make progress staggeringly faster than a larger number of pretty-good engineers working 9-5 under corporate processes and restrictions.

Your post is full of awesome!

Phase velocity is w / k. Group velocity is (dw)/(dk). If there's no dispersion, you scale k by a constant factor n slightly greater than 1. This slows both phase and group velocity by a factor of n, if w is proportional to k. If light is interacting with dark matter, you're right that it would interact with each particle extremely weakly, so there would have to be a whole lot of them. Also, probably the transitions would be of such high energy that you wouldn't get noticeable dispersion, so phase and group velocity would be equal.

I'm not in a position to comment on the likelihood of densities of dark matter. I'm not even sure how anyone could predict this with confidence, but you seem pretty sure of it. How do you set limits on the density of a particle with unknown properties you haven't observed yet (not facetious - genuinely interested)?

I'm a Canadian in the USA, and I'm not allowed to vote *anywhere*. F*ck you, Harper!

(Near re-post of http://slashdot.org/comments.pl?sid=2507746&cid=37936976)

OPERA shows light travels little bit slower than the fastest objects we've measured. A little while ago we heard that in galaxies far, far away, either the electric charge is larger, Plank's constant is smaller or the speed of light is smaller (http://slashdot.org/comments.pl?sid=2507746). If it's the speed of light that's smaller, the required slow-down is of the same order of magnitude as the factor by which photons are slower than neutrinos as observed by OPERA.

Here's my take. There's a field of undetected particles (dark matter?) that refract light a tiny bit, and this field was denser in the early universe. This field would not affect the apparent speed of light as an observer moves through it, just as (ignoring dispersion) light traveling through moving glass doesn't pick up the glass' motion vector (i.e. this wouldn't manifest itself as the Luminiferous aether, which is experimentally disproved). Light from the 1987A supernova would not be delayed too much relative to the neutrinos because most of the journey was through regions of space with low dark matter density.

There: three mysteries (dark matter, OPERA neutrinos and the fine structure "constant") all tied together with a bow on top. If you know more physics than I (honours undergrad) and you think I've missed something, please tear into this hypothesis, either here or on my blog: http://many-ideas.blogspot.com/2011/11/ftl-neutrinos-and-fine-structure.html. I look forward to hearing from you!

Best,

LeDopore

Thanks for the great answers. Take care!

My father works at a law firm, and they do remote incremental backups over ssh. I don't really expect that anyone is recording all ssh traffic for later cracking, but on the other hand it would be easy to do. Law firms have all sorts of documents, including a few really secret ones that could incriminate clients. Lawyer-client privilege exists for a reason.

In any case, if ssh fails in 20 years, law firms will be screwed. With documents like these, I have to think ssh isn't good enough, since a 10% chance (rough estimate) of losing all your data in 20 years is an unacceptable risk.

Dude, there *is* uncertainty and doubt about where technology will take us 100 years from now. We *are* sending some data over SSH that should be kept secret for a century. Unless we're sure that nobody will develop a big quantum computer this century (which is a hard stance to maintain - 100 years is a long time) we *should* be afraid.

Cue Strider: "Not nearly afraid enough. I know what hunts you."

High energy physics almost always refers to energy levels far above standard nuclear reactions. Lightning discharge is plasma physics, but the process behind how charges build up is still mysterious. The experiments conducted at CERN will not lead to technological advances you and I will see in this lifetime - indeed siphoning off money and talent to these projects *harms* the advancement of small-scale but useful science. I'm a scientist working on small projects, that's why I'm bitter.

I have nothing against particle physics per se, but the big projects are so inefficient that their funding is inevitable. When a project requires 10,000 human-years to complete, you can bet they have their grant proposals pretty slick, and politicians love to fund big endeavors, especially when pork barrels come into play. Small-scale geeks working in real-world situations that could have an impact on real-world issues have to beg for scraps from the table of big science.

I would be happy to see funding moved from high energy particle physics towards fields that could potentially yield a benefit to humanity. Like, for example, almost any other scientific investigation.

Nothing against you or your friend personally, but we still don't know how charge is built up in clouds to cause lightning. Why is there so much funding to study CP violation/Higgs bosons, etc. when we still don't understand lightning?