Universal Radio Grabber: the USRP

Nethemas the Great writes "The Universal Software Radio Peripheral or USRP created by Matt Ettus and Eric Blossom gives a new perspective on the radio spectrum, as in just about all of it from DC to 2.9Ghz. With the right software and daughterboards, their USRPs can capture FM, read GPS, decode HDTV, transmit over emergency bands, track peoples movement via their mobile phones, and much, much more. With prices starting at just $550 this new toy is accessible by most anyone."

Comments

The real question

[Umbral Blot]

The real question: how long before it becomes illegal to own or use one?

Re:The real question

[japhering]

The real question: how long before it becomes illegal to own or use one?

If it touches the Cell phone frequencies .. it already is ...

Re:The real question

[Tweekster]

so all transmitters are illegal?

hmm I did not know that. (Most transmitters can interfere with those frequencies already.)

Re:The real question

[Anonymous Coward]

"The real question: how long before it becomes illegal to own or use one?"

For some radio services, it may already be. One of the tasks the goverment communications regulators must do is to insure that radion devices do not interfere. In the US, the FCC has certain technical requirements and standards that are based on the sophistication of the end user and the intended use. For instance, the "type acceptance" requirements for a 2 way mobile radio for the land mobile service is much tighter than for the Family Radio Service. This is because almost no one but Tommy and his mother care if Tommy's mom is interfered with. On the other hand, a paramedic trying to save a heart attack victim must be protected from adjacent frequency interferande to insure his communications are reliable.

It doesn't matter how sophisticated software is, if unwanted signals cause interferance the basic RF circuits then the signal is permanently damager and possibly unrecoverable. For some applications, a very wide receiver is needed (TV, HDTV, high speed data). Because of that that receiver will allow in strong unwanted signals that will either overload the receiver or reduce the receivers sensitivity to weak signals. These signals will result in signal corruption.

Wether we like it or not, there will be technical requirements that will apply to this radio and those requirements will be the legacy requirements until the regulators figure out how to make a one size fits all regulation.

Re:The real question

[zippthorne]

Transmitters must be licensed. Even your 49 mhz walkie-talkie is licensed. It's not licensed to you specifically, it's type accepted, so the manufacturer can sell lots of them. If you were to modify it to transmit on another frequency, you would have an unlicensed transmitter and therefore subject to prosecution if you actually used it.

It makes sense to license transmitters. The EM spectrum of useful radio frequencies has finite bandwidth, and we must have some plan for use so that the most people can get the most benefit out of it. This includes astronomers, hobbyiests, emergency services, cell-phone users, television studios, and many more. Licensing solves the traffic jam problem.

It makes much less sense to license receivers. The radiation is there, passing through people, even. Frankly, I don't understand why anyone would think that I don't have the right to intercept any signal which passes through my personal space and process it however i please.

But that seems to be the case. Recievers capable of recieving cell-phone frequencies may not be sold. I am unsure of the legality of modifying or building your own equipment for that purpose, but I am sure the cell-phone companies have lobbied hard to make that illegal as well. As a longtime desirerer of encrypted cell-phones, it has frustrated me that they want to transmit "in the clear" and just make it a crime to recieve, especially as equipment from before there were cellphones exists that has no hardware blocks on those frequencies whatsoever. Fortunately, CDMA forces at least a rudimentary level of quasi-encryption.

Re:The real question

[Intron]

it has frustrated me that they want to transmit "in the clear"

Where "they" means the NSA, in this case.

Re:The real question

[egomaniac]

It makes much less sense to license receivers. The radiation is there, passing through people, even. Frankly, I don't understand why anyone would think that I don't have the right to intercept any signal which passes through my personal space and process it however i please.

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night? After all, her naked body is reflecting electromagnetic radiation into my personal space. Amplifying it into a visible image, digitizing it, and making it available on the Internet seems like a perfectly logical step, doesn't it?

People have an expectation of privacy. They expect you won't be sneaking around peering into their windows at night, and they expect you won't be intercepting and decoding their personal telephone calls. Yes, you have the right to decode electromagnetic radiation. And yes, the callers have a right to privacy. Any time two different rights conflict, one or the other has to take precedence. Privacy is a much more desirable-to-society right than is the ability to spy on our neighbors, and so privacy wins.

Re:The real question

[esper]

No, I rather doubt that it does. I remember hearing complaints about the decision to simply make it illegal for scanners to listen to cellphone frequencies instead of properly encrypting cell traffic going all the way back to the dawn of cellphones, well before we had a War on Terror or large-scale domestic snooping. I expect that this is the work of cheap cell providers and phone manufacturers, not nosy spies.

Re:The real question

[makomk]

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night? After all, her naked body is reflecting electromagnetic radiation into my personal space. Amplifying it into a visible image, digitizing it, and making it available on the Internet seems like a perfectly logical step, doesn't it?

So I take it you think that we should ban all night vision scopes, then? Because that's effectively what's been done...

Re:The real question

[esper]

Yes, but it's quite simple to cater to both the right to listen to the EM spectrum and the right to private phone calls: Stop making/using cellphones that transmit in the clear.

As for the neighbor analogy, you could just say "close your curtains", but that doesn't really hold up because it's something that the neighbor has to actively do to avoid having her privacy compromised. Encrypting cell transmissions can (and should) be automatic and transparent to the user, so the analogy breaks on that point.

Re:The real question

[TheGratefulNet]

People have an expectation of privacy

in the US?

in the MODERN US?

(have you not been reading the news at all, over the last say, year or two?)

Re:The real question

[jrockway]

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night? After all, her naked body is reflecting electromagnetic radiation into my personal space. Amplifying it into a visible image, digitizing it, and making it available on the Internet seems like a perfectly logical step, doesn't it?

Actually, sounds pretty logical to me. If your neighbor is concerned, she should get some high-tech radio jamming technology called "insulation". Saves on heating, too.

Re:The real question

[ultramk]

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night? After all, her naked body is reflecting electromagnetic radiation into my personal space. Amplifying it into a visible image, digitizing it, and making it available on the Internet seems like a perfectly logical step, doesn't it?

Ok, I'm with you so far.

URL?

m-

Re:The real question

[david.given]

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night?

I'm not sure that's a valid analogy --- there is, after all, a big difference between passive scattered photons that have occurred simply because an object is in a particular space, and explicitly generating EM waves with the intent to communicate information.

Yes, you have the right to decode electromagnetic radiation. And yes, the callers have a right to privacy.

Why? And that's a serious question. Why do you consider there to be such rights?

Talking about 'rights' is dangerous, because using that word leads you to believe that they're automatic. They're not. They are granted to you by the social contract in return for certain services (the major one being that you, in turn, adhere to the social contract). The key issue is that you must pay for them, in one way or another --- these privileges are expensive.

In this situation: can the social contract really afford to decree that people may not listen in to other people's EM-broadcast conversations? I'd suggest not. After all, it's practically unenforcable; there's no way of catching such eavesdroppers, and the only alternative is to go after the equipment manufacturers. Not only is this incredibly hard these days --- as this device is showing --- but doing this is going to have a major chilling effect on all kinds of fields of endeavour, from electronics manufacture to hobbiest radio hams. I simply don't think it's worth it any more. I'd rephrase as follows: you believe that the social contract grants you an expectation of privacy.

Re:The real question

[ps_inkling]

The illegal to listen to cellphone frequencies comes from the Newt Gingrich and Clinton era. Bah, even before then. Some other bills. Your congresscritter Billy Tauzin was the original sponsor of the Electronic Communications Privacy Act.

Your searches may vary -- this is enough to get the ball rolling.

Re:The real question

[david.given]

Just to point out that that last sentence shouldn't be there.

(mutters) friggin' textarea boxes...

Re:The real question

[tacarat]

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night? After all, her naked body is reflecting electromagnetic radiation into my personal space. Amplifying it into a visible image, digitizing it, and making it available on the Internet seems like a perfectly logical step, doesn't it?

Ummm. Radio transmitters are much more along the lines of your neighbor changing or whatever in the middle of a crowded public area with people that could turn around and watch at any point. Your example, peeking into her window, is more deliberate. For one thing, it's targeted. You knew specifically who you wanted to observe. Another is that she made an attempt to protect her privacy by going inside. In this example, you've taken steps to circumvent this by searching for and exploiting an opening (earn your white hat and let her know her curtains are open).

Personally, I'm waiting for the day when SETI gets sued (or disintegrated) for intercepting alien phone calls. I'm betting the first decoded message is for 1-900-UFO-HOTY

Re:The real question

[drinkypoo]

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night?

But it is legal. Anything you can see from your property is fair game to look at, at least in the USA. Probably not legal to record it; almost certainly not legal to distribute if you do.

It's totally legal to look at naked people in their own house if you can see them without trespassing. If you choose not to cover your windows you give up your reasonable expectation of privacy.

Amusingly you're not legally trespassing until you have been told to leave, at least in California. Those "no trespassing" signs don't mean shit either, unless your property is completely encircled with fence and you have a gate which is locked.

Re:The real question

[DragonWriter]

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night?

It should be legal for you to build or own a night-vision scope. (Parallel to owning a receiver that can receive, among other things, the bands that cellular phones transmit in.) It might be that it should be illegal for you to use it for certain purposes.

After all, her naked body is reflecting electromagnetic radiation into my personal space. Amplifying it into a visible image, digitizing it, and making it available on the Internet seems like a perfectly logical step, doesn't it?

Well, no, it doesn't.

Re:The real question

[egomaniac]

But it is legal. Anything you can see from your property is fair game to look at, at least in the USA. Probably not legal to record it; almost certainly not legal to distribute if you do.

It's totally legal to look at naked people in their own house if you can see them without trespassing. If you choose not to cover your windows you give up your reasonable expectation of privacy.

Spying on people when they have a reasonable expectation of privacy (as when in a darkened room) is illegal in most localities in developed countries throughout the world. The US is no exception -- most states have anti-voyeurism laws which would prohibit using night-vision scopes to peer into darkened windows.

Re:The real question

[ceoyoyo]

Here in Canada it's legal to use a radio scanner to listen to whatever you want. It may be illegal to USE that information though.

Re:The real question

[Anonymous Coward]

Radar detectors. Illegal in several states and DC. Interestingly, since you could configure this device as a radar detector, might it already be illegal to own in the Nation's Capital (America's benchmark for Taxation without Representation)?

DC

Re:The real question

[Anonymous Coward]

Okay, we will assume you are gay then. In that case, search for her, insert his, and then you should agree.

It's a joke, not a personal attack. Laugh.

Re:The real question

[jonwil]

I believe GSM (and by extention UMTS 3G which is based on GSM) features encryption for over-the-air voice traffic. How strong it is (and whether "The Man" can listen in by plugging into the base station) I dont know.

Re:The real question

[El Torico]

Amusingly you're not legally trespassing until you have been told to leave, at least in California. Those "no trespassing" signs don't mean shit either, unless your property is completely encircled with fence and you have a gate which is locked.

This is another reason I'm glad I don't live in California. Really, I don't see what is amusing about trespassing.

Re:The real question

[Bluesman]

In the U.S., at least, we believe that there are rights that are "automatic." The U.S. Constitution, which too few people read, defines these as inalienable rights that no governement or other entity can take away.

I'm just intending to clarify things, as your social contract statement seems to indicate that you believe that authority can grant or take away rights at whim, as long as it's written down somewhere, or otherwise generally agreed upon. I'm assuming this is a European idea.

The ramifications are that U.S. citizens have a basis for determining when a government has overstepped its bounds (whether they actually do is a different story), where the social contract idea seems to provide little justification for being critical of authority. I'm sure in either case it doesn't make much difference practically speaking, but we're coming from fundamentally opposed viewpoints. (i.e. humans have certain rights no matter what, vs. the only rights you have are what society agrees on.)

But, you're right, there's no inalienable right to receive RF signals and decode them, as far as I'm aware, in the U.S. Constitution or otherwise.

Re:The real question

[Detritus]

It's optional, weak, and usually turned off in the USA.

Re:The real question

[Mac Degger]

The first part is legal; expectations of privacy are a fine thing, but if you parade around naked in front of your window, you should have the expectation that a) someone will look and b) that you're basically signing away your privacy. Same as a streaker saying: "Hey, don't look at me naked!"...that's a rediculous position to take.

The distribution part is a different matter altogether, regulated by things like copyright, IP ownership, etc. Thing which a model-release form are there to solve.

Re:The real question

[zippthorne]

According to the paradigm of absolute personal soviergnty over all radiation that passes through you, yes. Of course, this ability should be well publicized, and the practice of properly insulating houses to prevent exactly that sort of thing from happening should be standard. The reason I propose that this should be the policy is that if it is the known policy, people would have no expectation of a privacy that doesn't actually exist.

If you make it illegal to look in houses like that, you only get to punish the creeps after they commit the act. If you make everyone aware of the risk, you can prevent the act from occuring at all.

Re:The real question

[rthille]

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night?

Yes, definitely. In fact, if she can be seen from the street/sidewalk, she could possibly be charged with indecent exposure. If you want privacy, close the blinds. Now if you have to take a step even one foot on her property to have the necessary vantage point, then you would be a 'peeping tom' and in violation of the law.

Re:The real question

[sumdumass]

Well it doesn't even have ot go that far. Cutains, Closed windows, sleeping with the lights out or even covers on can defeat all consumer nightvision systems that don't emit a light.

Night vision needs some light in order to function. It operates of ifrared and visible light waves. Ifrerad waves (the light you can't see) don't putrude very far (compared ot regular light sources). When to see images on the news were a battlefield is lite up like daytime, it is because of a flare that was shot up or some other (abient?) lighting. Glass tends to reflect this type of lighting too so the probability of anyone using nightvision to see something with detail inside the neigbors house is slim unless they are either directly in the window (other laws apply) or they are injecting artificial light into the room. Otherwise, the neigbor would need some sort of light on, the curtains open, and probably the windows open. (in other words, she is wanting someone to see her or increadibly naive.)

Re:The real question

[drgonzo59]

The analogy was stupid in the first place. There is blurry line between "I am watching my neighbour" and "she is showing herself to me". For example if she walked around naked by her open window, in full light and plain view of my children while they are playing in the yard, she would probably be cited for exposure. Anyone stupid enough to not close the blinds/curtains when they are naked -- don't have much to complain.

So I agree with one of grand(grand?)parents that if the RF radiation is allowed to pass through my body, I should be able to decode it. Security should be based on encryption not on the hope that nobody will _probably_ listen in because we made the receivers illegal...

Broadcasting un-encrypted stuff is like shouting your private conversation from the top of a hill for the whole town to here. Now if you used a foreign language that nobody except you and intended recepients speak (think Navaho!) then you should be fine.

Re:The real question

[zardo]

You want privacy you transmit all the radio signals you want, UNDERGROUND. Talking on a cellphone is like walking around outside, naked.

Re:The real question

[StikyPad]

Broadcasting is like speaking in a public place: The expectation of privacy does not apply. Additionally, the OP never suggested using a radio to spy on his neighbor. But to answer nonetheless, I don't believe a technology should be illegal just because it could be used for illicit purposes. (Not to be confused with technology which exists solely to facilitate illicit or illegal activity). We have plenty of laws to protect against and enforce specific violations or misuses already. If you don't believe that those laws will stop people from engaging in certain activity -- and you're probably right in believing that -- then there's no reason to believe that outlawing the technology altogether will have similar results.

Re:The real question

[StikyPad]

I'm betting the first will be:

"Helloooo??? Is this thing on?" ...
"Can you hear me now?"

Re:The real question

[Anonymous Coward]

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night? After all, her naked body is reflecting electromagnetic radiation into my personal space. Amplifying it into a visible image, digitizing it, and making it available on the Internet seems like a perfectly logical step, doesn't it?

This might be the single most stupid fucking thing I've ever seen posted here. Jesus Christ, you are a dumb motherfucker. Or, a Republican. Or, both. I don't even know how to begin to address this. Don't post any more you retard. And, the idiots that made this 4 Insightful?!?!? You're as freaking stupid, if not more so. Dipshit bastards.

Re:The real question

[hany]

Well, I like my privacy too. But I still have to disagree with you because of your argument about privacy winning over interception of signals passing through space controled by interceptor.

Why? In general, because of physics (and human individualistic nature).

For example, one argument can be that if "your" signals are truly yours (or at least that notion is enforced by society) than when your signals are passing my property I can sue you. Because, if you say those signals are yours than I say "fine, but get them out of my property" - I respect your signals, you respect my garden, my house, my body, ...

In such scenario it'll be essentialy impossible to use radio (and other menas of communication) because all sorts of people will not allow to pass it through their property. Or society should say "signals are more than physical property" but it'll be ... well ... very very confusing for a lot of people and hard to enforce without a lot of people feeling badly about it.

So that much about "your" or "mine" signals - if I do not want you to know what I'm doing, either I do not pass my signals through your space or I take a risk and do.

Question left over for some other exercises is: what about my ability to block signals going through my property (i.e. not letting them pass)? Would it be OK for me to block them? (IMO yes, but than I have to expect and accept that others will do the same so in order to have the communication, we muttualy agree not to sheald signals, at least as long as they are considered harmless to our health and environment).

And now back to privacy: So if essentaly we agree that I can see (analyze, receive, ...) whatever is passing through me and my property then we essentialy agree that anybody can spy on anybody as long as he is just passive observer (i.e. not stalker actively seeking and intimidating "prey" etc.).

How do we protect our privacy then?

One way is to block the signals going out or not sending them at all. In case of your example, your neighbour, if he/she values his/her privacy, should not undress near the window etc.

Other way, in the broader sense, is "enact" that while everybody can spy, that everybody have the right to spy. So everybody will know that and will take that into account. And as long as there is no big discrimination (like "police can spy on you but you can't spy police", "white guys can spy on black guys", etc. - artificial scenario not based on physics, same with so called IP rights as enforced by *AA, and beware, I am for IP rights while I'm programmer, but not as artificaly broadened and out of real physical world as requested by some), I think that it may also be better than now, because it will eliminate at least those "bad things" which are done when a guy thinks nobody sees him (and I mean both small hooligan and big politician - all should be watched closely :) .

Re:The real question

[hany]

As I am all for peacefull coexistence of all the people (and ... well ... all and everything) in the universe I learned so far that one thing is what the law says, another thing is what is enforced and also another thing is what people actualy do.

Supreme Court may ruled as you wrote but as long as you're using that lamp you're leaking signals which others are able to detect so if you're not blocking those signals (so that interception is impossible) you're taking risk because it may not be police who'll observe you using the lamp. Or there may be some "big event(TM)" after which Supreme Court will rule otherwise ...

So in other words: You may act like gravity is always pointing downwards no matter what Supreme Court says, because that's physics not some "bill of rights".
But you should not run naked through the streets no matter how many laws there are to protect you from humilating yourself (if you are ugly) or financial harm (if you are beautifull and you just lost a lot of possible income because now a lot of people saw you naked for free and wont be that much interested in you anymore :) .

If you want your privacy that much, you have to remodel our universe - or better yet, make your own (with physics which does not leek that much info about you) and let others keep current one. :)

Re:The real question

[yusing]

People have an expectation of privacy.

Anyone using wireless for communication who has an "expectation of privacy" is, and always has been, just fooling themselves ... unless they themselves have played an intelligent part in the careful design of the equipment to avoid interception. Even that will only work for a short ... sometimes a very short ... time if someone with time and expertise is interested in what they're saying.

Privacy is a much more desirable-to-society

Tell that to your government ... they don't seem to have heard that message.

Re:The real question

[cduffy]

Those "no trespassing" signs don't mean shit either, unless your property is completely encircled with fence and you have a gate which is locked.

Not here in Texas, at least. At our last Neighborhood Watch meeting, the officer who was speaking said that those signs count as a command from the homeowner to leave, and allow him the ability to arrest folks who are acting suspicious on someone else's property (whereas otherwise, the best he could do would be asking them to leave).

Now, in terms of shooting folks who are trespassing, the sign may not be sufficient alone (I haven't taken the concealed-carry class yet, and so am quite unfamiliar with the applicable law) -- but in terms of making trespassing into an arrestable offense, it is indeed.

Re:The real question

[matfud]

Not quite true.

A social contract does not require Government. What the founding fathers did is set up a social contract and then explicity stop the Government from modifying specific aspects of it. The idea that anybody has "automatic" rights is silly without a society that allows everybody to have those rights. Admittedly you could claim those rights if you did not live in a society but you would not have any protection of them.

In the UK there is no explicit limitation on the government wrt allowing/denying rights and little written down to "grant" anything to anyone. There is instead a huge pile of law that supports the edifice.

Re:The real question

[m874t232]

So it should be legal for me to use a night-vision scope to look into my neighbor's bedroom window at night?

Yes.

Amplifying it into a visible image, digitizing it, and making it available on the Internet seems like a perfectly logical step, doesn't it?

No, making it available on the Internet is not. That's where society draws the line for specific kinds of content. That's not so much to protect people against this case, but to protect people against fabricated data.

People have an expectation of privacy.

And when they use curtains, their expectation will be fulfilled.

Privacy is a much more desirable-to-society right than is the ability to spy on our neighbors, and so privacy wins.

I'm all for strong privacy protection. But protecting people who decide to waltz around naked in front of curtainless windows from their own stupidity has nothing to do with privacy protection.

Re:The real question

[gebbeth]

People have an expectation of privacy. They expect you won't be sneaking around peering into their windows at night, and they expect you won't be intercepting and decoding their personal telephone calls.

Expectation of privacy has much to do with the circumstance. Someone standing behind a closed window shade has an expectation of privacy, someone standing in a window visible from the street or a neighbor's house (with no window shade) does not. Even if someone used a visual aid (binoculars, passive light amplification) if the window in question has a clear line of sight, then there can be no reasonable expectation of privacy. The exception would probably be if your house was isolated in some way.

Re:The real question

[Anonymous Coward]

Like file sharing technology, it would be quite difficult to legislate against it as there are both legal and illegal uses for it.

That said, if it was used in a way that the press could link to the loss of a life (say, someone jamming/flooding an emergency band) there would probably be enough wild hysteria for the government to go ahead.

Some (possible) interesting uses (if I understand what it does correctly):

Intermittent cell phone jammer Broadcast a sufficently loud signal to block out local cell reception. If it was constantly on, you'd have the local authorities knocking at your door in no time. Better off detecting the handshake and then introducing errors to worsen the signal to noise ratio at that frequency. Integrated electronic warfare system It could pick up and triangulate the source of a police radar from various antennae on your car and then attempt to burn/jam out the receiver by broadcasting a focused beam at the radar. Finally, a use for the PC in your car (what do you mean you don't have one?).

Most interesting of all is that guy's plan to build a "passive radar system".

Blossom is working on a passive radar system... His passive radar reads in the ambient radio waves from existing sources, like FM stations and cell towers, and uses them to build a map of the area. At the end of his research, he plans to have "this little gadget that you can plug into a laptop and see what's flying around. We're hoping to see stuff on the order of 50 to 70 kilometers away."

This sounds like a cheap way to seriously degrade the stealth capabilites of aircraft (http://en.wikipedia.org/wiki/Stealth_aircraft). Dozens of these boards, scattered across the city, linked to laptop computers operating over a civilian telecommunications network (which would be difficult militarily or politically to destroy) create a multistatic radar, increasing the Radar Cross-Section (RCS) of stealth aircraft. This could be a serious blow to the F35 which only has a reduced frontal RCS as a result of cost saving measures. The F22 and B2 should still do alright, especially if they can get lost in ground clutter.

It's ironic that the ingenuity of (mostly) US developers will help degrade the effectiveness of something that the US taxpayer has spent 50 years supporting the development of. These boards are easily replicated by any second rate university. It is the creativity and resourcefulness of the software development community that will allow them to be used in this way. It's especially ironic that it will be harnessed by those who would not knowingly allow such creativity under their own regimes.

Re:The real question

[dmd]

Who decides what "fence" is? If I string up a piece of fishing line, is that a "fence"? What about a two foot tall white picket fence? Does it have to be ten foot tall razorwire fence before it counts?

Why can't the "no trespassing signs" themselves count as a fence?

Re:The real question

[JCOTTON]

I am interested to know from where you know this "...you're not legally trespassing until you have been told to leave, at least in California...". And more importantly, does it apply in other states? mail me

Re:The real question

[Anonymous Coward]

Amendment IX

The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.

Amendment X

The powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively, or to the people.

Re:The real question

[trentblase]

I'm not saying this officer's advice is wrong, but I've learned never to accept legal advice from the police -- they are rarely certified to practice law, and are often wrong.

Re:The real question

[JesseMcDonald]

This could be a serious blow to the F35 which only has a reduced frontal RCS as a result of cost saving measures. The F22 and B2 should still do alright, especially if they can get lost in ground clutter.

It's ironic that the ingenuity of (mostly) US developers will help degrade the effectiveness of something that the US taxpayer has spent 50 years supporting the development of.

I, for one, would rather look forward to the potential improvements in defensive technologies (such as improved missile defense systems and better radar detection of threatening aircraft) than lament the reduced effectiveness of our stealth technology, particularly as stealth abilities appear to be primarily offensive in nature (at least when used against the ground-based radar systems of foreign countries). Can anyone name a good defensive use of radar stealth technology, for that matter? I don't know of any myself.

I think that if we put even half the effort into improving our defensive technologies as we put into subduing every potential attacker, we would (for all practical purposes) be able to simply ignore them by now. Consider that the only countries that can attack the U.S. by land are Mexico and Canada; everyone else has to attack either by air (planes and missiles), or by sea. Either way, the primary obstacle to prevention is accurate and reliable detection of the attack, which this passive radar SDR system would help to eliminate. Missiles would still be an issue, since they're hard to take down even with good radar tracking, but I'm optimistic that we could find ways to do it effectively given enough time.

Handling interference issues would appear to me to be fairly straightforward: just use a few of these SDR systems to track all the transmitters operating in the area. If one person's transmitter interferes with something important (like an emergency-band transmission), make the operator of the interfering equiptment liable for the consequences. The same principle could be applied to personal and commercial use, with the first user of a range of spectrum granted priority use within the receiving area and corresponding civil protection from interfering transmissions.

Re:The real question

[Anonymous Coward]

What if she doesn't have/can't afford blinds for whatever reason? What if I fly a plane to take aerial photos through her skylights? If she closes her curtains instead of her blinds, does she not expect/deserve privacy? After all, I might use infrared cameras to see through them. Taken to an extreme, what if I can circumvent every attempt she makes to conceal herself? Is that still fair game, so long as I don't go on her property? Should she still be charged with indecent exposure?

Re:The real question

[rthille]

Hey, I'm not saying it's 'ok' for someone with x-ray vision to hang out outside the women's locker room at a gym, I'm just talking about what is currently legal/illegal (in CA-US at least).

Re:The real question

[Anonymous Coward]

You responded to the question "Should it be legal?" [emphasis mine] with "Yes, definitely." You were not addressing whether it is or is not legal with that response. Thanks for correcting yourself, though.

Re:The real question

[rthille]

I guess I should have re-read the thread before I responded :-) Two days after I post something I've forgotten all the context. I still say that if you can afford windows, you can 'afford' cardboard or sheets or something for 'blinds'.

Ouch $550

[9mm Censor]

I would hardly call _starting at_ $550 accessable to almost anyone.

Re:Ouch $550

[sk8dork]

accessible to anyone that would find use of it, or more importantly, mis-use of it.

Re:Ouch $550

[davidbro]

Especially since it appears that the $550 gets you the motherboard, without any radio modules. The $550 will get you something that you need to spend more money on until it is functional. I think this is just a case of the journalist not really digging into it more than superficially, but the guy the reporter was talking to should have also pointed out how much a minimally configured system would cost.

At a minimum you will need the motherboard, a radio module, some cable (which isn't cheap, especially for doing higher frequency work), and a useful antenna (those tiny ones they advertise on the website will be fine for higher frequencies, but if you want to do anything else, you are looking at an external antenna and more cable).

However, this is a very cool project. A lot of good will come from this work. But $550 is not the starting price. The starting price is higher.

Re:Ouch $550

[Anonymous Coward]

Almost anyone can get a job at second (or third) job McDonald's working minimum wage. Even at part time it should only take a month or two to pay for it. Sounds accessible to me. Perhaps not practical or easy, but definitely accessible.

Re:Ouch $550

[Lithgon]

That's why they said: almost anyone.

Re:Ouch $550

[wild_berry]

Well, you've got that kind of money to thow on a Playstation 3 don't y... ...oh.

Re:Ouch $550

[morgan_greywolf]

Note also that if you intend to do any FPGA programming with the USRP, according to this faqyou will need to spend and additional $300 to get 2 of each of the BasicRX and BasicTX boards for debugging purposes.

Re:Ouch $550

[RedMagus77]

It makes you wonder what basic "accessable price to everyone" is considered. $550 is not in that range though, in my opinion. Also, why would most people want to own one of these kits? Does the average person really want to know or care about what's floating over their airwaves? It seems like another niche item to waste money on.

Re:Ouch $550

[222]

SCE head Ken Kutaragi was quoting as saying "It's probably too cheap."

Re:Ouch $550

[Mac Degger]

$550 is cheap. Think of a lab setting, where you need equipment for every band you're investigating. That equipment is expensive; a grand is cheap! That's who this equipment is for.

Re:Ouch $550

[stienman]

For those that are curious, I looked up the cost of the components.

Buying the chips in small quantities leads to about $100 just for the 4 main chips (two analog interface chips, one FPGA, one USB microcontroller). The PCB is likely to be around $20 if it's more than a two layer and in small quantities. The labor to assemble just a few of them is likely $50-$100.

$550 isn't a bad price. But there's a reason the PCB isn't open sourced like all the other design files - the company wants (needs) to make money and recoup its investment.

Still, one sufficiently motivated could reduce the cost of the entire board and probably include the popular generic modules to the $200 range if they were able to get a comitment to purchase from say 100 people.

It's a neat concept, and one I'd like to get into, but right now it's not something that you use so much as tinker with. It's for researchers and hobbyists. Once there is real time hdtv decoder software in linux that runs with this, and a good tv/radio record/pause/skip program, as well as a nice simple scanner application then it will become something worth having for the general linux hacker.

I think someone could make a good bit of money if they made a small module that just had one A/D interface, the FPGA, a cable modem tuner, and the usb microcontroller. It could sell for $100, which would be cheap enough for regular hackers to get it and start making really cool tv/radio applications for.

-Adam

P2P Telephone?

[Mantrid42]

My first thought on seeing this is, if it can simultaneously recieve and transmit, couldn't you create a truely decentralized telephone system? With the NSA wiretapping everything, isn't a simple solution to just take away the wires?

Re:P2P Telephone?

[CRCulver]

Amateur ("ham") radio operators have had a decentralized telephone network for almost a century. However, the FCC regulations governing transmission on bands accessible to the public require that no encryption be used so that the FCC and volunteer ham regulators can monitor activity.

Re:P2P Telephone?

[Anonymous Coward]

Because broadcasting your conversation is much more secure?

Or maybe because warrants aren't required to listen in on wireless conversations so there's no controversy?

Re:P2P Telephone?

[Wesley Felter]

If you want some sort of wireless P2P phone system, you'd probably be better off starting with a PDA with a high-power 802.11 card in it. SDR sounds like overkill.

Re:P2P Telephone?

[misleb]

Each device would need a unique channel and each device would need to be able to transmit the total distance bbetween any two phones. And that just makes wiretapping easier. For everyone, not just the NSA. Really, the simple answer to wiretapping is just encrypted VoIP. And if you want wireless, use a WiFi phone.

-matthew

Re:P2P Telephone?

[Eravnrekaree]

I dont think using radio signals, instead of wires is really going to help your privacy much. How is transmitting something over the air where anyone can recieve it better than sending it over wires, which someone has to tap into physically?

If you really want privacy, what you want is some really strong, good encryption. I would, if you are paranoid, encrypt your messages many times each time with a different key.

People often claim wireless is the solution to everything. It definitely is not. RF spectrum is very dear and limited, and there are often quite a few fights over who will get to use which bands. Its not an unlimited resource. Fiber optics can deliver far greater data capacity than wireless ever will.

Re:P2P Telephone?

[Intron]

How is transmitting something over the air where anyone can recieve it better than sending it over wires, which someone has to tap into physically?

Radios don't have an IP address.

Re:P2P Telephone?

[billcopc]

Thing is, the NSA doesn't physically "tap" into anything anymore, they just get the telco to send them a copy of the audio stream. This way they can monitor as many people as they like, simultaneously. Heck, they could keep archives of every single call you make, automatically. Sure it requires massive storage, but what's money when you're the government ? :P

Re:P2P Telephone?

[Anonymous Coward]

Bullshit.

I can't vouch for how long distance traffic is handled once it leaves the local office, but if any agency wants to listen in to phone calls a technician has to physically install a tap. I suppose if you're a conspiracy nut the long distance companies may send out an "audio stream" of the calls being routed through their hardware, but there is no way anything like that could possibly happen on a local level. Of course, there isn't any chance that's possible anyway as the expense to the long distance companies would be huge. What you suggest would require massive dedicated connections to the NSA from every long distance switching site. The hardware to put that in place isn't exactly free, even on a governmental scale.

Re:P2P Telephone?

[Phleg]

I would, if you are paranoid, encrypt your messages many times each time with a different key.

Please stop suggesting things like this without any reasonably in-depth knowledge of cryptography. Encrypting something multiple times does not necessarily increase security (c.f., Double DES).

Re:P2P Telephone?

[Phleg]

Even more specifically, encrypting messages repeatedly with several keys is entirely useless if the cipher forms a group, in which case E(E(P,K1),K2) == E(P,K3) and you don't gain any benefit whatsoever.

Re:P2P Telephone?

[billcopc]

The hardware to put that in place is peanuts compared to what an actual wiretap costs, equipment, time, wages etc.

How is this legal?

[Valdrax]

Aren't radio transmitters/receivers legally required to not be able to access certain bands without proper licenses?

Re:How is this legal?

[vinn01]

I know that certain frequencies must be blocked by any radio receiver sold in the US.

A friend of mine bought WinRadio from Austrailia in order to get the full spectrum version.

Re:How is this legal?

[prichardson]

From their FAQ... http://www.ettus.com/faq.html

Are there any license requirement for the transmit or transecive daughterboards?

The USRP is sold as test equipment, which has no licensing requirements. If you choose to use your USRP and daughterboards to transmit using an antenna, it is your responsibility to make sure that you are in compliance with all laws for the country, frequency, and power levels in which the device is used.

Re:How is this legal?

[Bloke down the pub]

The USRP is sold as test equipment [...] If you choose to use your USRP and daughterboards to transmit using an antenna, it is your responsibility to make sure that you are in compliance with all laws

Reminds me of a story I heard: during prohibition, you could buy a health drink that was basically grape juice concentrate. The instructions said something like "Do *not* dilute and certainly don't add yeast. If accidental yeast contamination occurs, don't even think about leaving it in a warmish place for roughly two weeks".

best thing since sliced bread

[itak.karstaag]

Now we can stalk the girlfriends we don't have and spam emergency bands with crap!

In all seriousness, though, this sounds like a lot of fun. The legal uses, I mean.

Uh, prices don't begin at $550

[drinkypoo]

Just the motherboard is $550. You will need at least one daughterboard to actually do anything. The cheapest ones (2-200MHz transmitter, 2-300MHz receiver, 30MHz transmitter, 30MHZ receiver) are $75 each. In order to just transmit, you will need to spend at least $625, unless you are a member of "TAPR, AMSAT, SARA, or SETI League" in which case you get $25 off the motherboard.

Interestingly, though the sales page lists "extra" power supply, usb cable, and standoff sets, nowhere on the sales page does it actually say that the unit comes with any of these things. If you're going to run a business, run it right.

Re:Uh, prices don't begin at $550

[slashhax0r]

Everyone needs to quit bitching. This thing is great. Look at what a "DC to daylight" ham rig costs you.. and you have no where near the control.

Re:Uh, prices don't begin at $550

[drinkypoo]

I'm bitching more about the story submission than anything else, although I do think the website is incredibly unprofessional. If they like fielding annoying questions in email, like does it come with the basic stuff you need to use it, then that's OK with me, I just think it's stupid. The price is great, but the story submission is dumb.

Homebrew SETI?

[superdan2k]

Imagine a not-quite-Beowulf cluster of these -- your own homebrewed VLA. It'll receive in the "waterhole band", and VLBI ain't too hard to figure out. Set up enough ground stations and switch between them as-needed to compensate for what you're viewing and the rotation of the Earth, and you've got a fulltime radio telescope with a dish effectively as large as the earth, whenever you want it...

Open source radio astronomy anyone?

Re:Homebrew SETI?

[MrShaggy]

Upon opening the box, you can exclaim, 'Oh my GOD! Its full of STARS!'

Re:Homebrew SETI?

[sik0fewl]

We could call it... SETI@home!

Re:Homebrew SETI?

[charlieo88]

Didn't Charlie Sheen already do that?

Re:Homebrew SETI?

[patchvonbraun]

The Gnu Radio code used with the USRP already includes a couple of radio astronomy applications--one for spectral and continuum work, and the other for pulsars. Still very rudimentary, but the spectral application could easily be morphed into something more useful for SETI. Keep firmly in mind that doing amateur SETI observing with a small dish is a dicey proposition, at least based on the current wild-assed guesses for ETs radiated power budget :-) A flotilla of small dishes, all observing the same patch in the sky could concievably build a SETI array to increase effective antenna size, but maximizing the sensitivity requires phase coherence among all the antennae. Not easy to achieve at the amateur level... The Gnu Radio SDR system that's used with USRP is a very flexible framework for building a great number of specialized or general purpose radio applications. It wouldn't take long to put together a SETI watcher application, using probably the DBS_RX daughterboard, which would nicely cover the water hole.

Whee!

[houdini_cs]

Looks like a fantastic project piece, but the price tag means I won't have one any time soon. $550 is steep for a toy.

Re:Whee!

[Ryz0r]

>>$550 is steep for a toy.

Try telling that to Sony..

Re:Whee!

[houdini_cs]

I don't own an XBox 360, and I probably won't buy a PS 3. You could say I've already told them :)

Probably already is.

[Anonymous Coward]

Probably already is.

If it's just receiving radio, that's probably ok. The hard part would be the transmitting. End users would have to have a license.

I don't give a shit though. I want one.

It seriously pisses me off that the U.S.A. is now almost entirely anti-innovation.

Combination of things like DMCA, software patents, and fascist-like coordination between big business and government has hurt. In a few years I expect all major technological development will be done outside the country.

Fucking bunch of morons in government. It's suppose to be 'In God We Trust', not 'We Trust Money, our God'.

Re:Probably already is.

[Beryllium Sphere(tm)]

It's illegal to sell something that can receive in the bands for cellular voice. Haven't check whether this one's at risk.

Re:Probably already is.

[arose]

It's illegal to sell something that can receive in the bands for cellular voice.

How do people manage to sell wire then?

Open Spectrum

[Doc Ruby]

Who's got the rest of the software that combines multiple SW radios with phased arrays of smart antennas? A mobile "phone" that can transceive in any band without any required registration (of frequency, time or code) because its signal is unique due to its unique spatial position. Bandwidth would be limited only by the power efficiency of the electronics.

Nothing new here...

[Jizzbug]

It has been on the market since Nov. 2004.

http://www.comsec.com/wiki?UsrpProgress

Re:Nothing new here...

[Anonymous Coward]

I'm glad some other people feel the same way, this has been covered on Engadget, Boing Boing, Digg, and now Slashdot because some 'intrepid' Wired reporter found it finally after nearly two years. I've had my USRP ever since it was mentioned on the Open EEG newsgroup, some other electronic hacker forum, or just typed 'open' in front of radio in Google. Figured by now this was common knowledge since Matt Ettus was even at the last Make conference. Omg btw have you heard of the Open EEG project too? I should be a Wired reporter.

NOW I can finally

[EW87]

Stalk Vida Guerra via cell phone...

Sure it is...

[Hamster Lover]

Hell, it's actually $50 less than a PS3! Buy two at that price, one for each hand so you don't feel compelled to shoot Jack Thompson in the face.

Cracking satelite using regular TV card

[yoriz]

There already exists some software that decodes some protected satelite channels using a regular Hauptpage TV card. Does that work by (ab)using the Hauptpage to only pick up the signal and then do all the processing *in software* (similar to the USRP in the article) rather than using the Hauptpage hardware?

If so, that would mean were already able to do TV decoding in software for years!

Re:Cracking satelite using regular TV card

[elleomea]

There are many TV/DVB cards that do their processing in software, it's probably one of these cards that you're refering to rather than somehow forcing a hardware decoding card to output the unprocessed data. I can easily receive the encrypted DVB-T channels with my Hauppauge Nova-T USB device (though I've made no effort to try and decrypt them).

Re:Cracking satelite using regular TV card

[Xciton]

No no no. The two projects are COMPLETELY different. Please don't compare the two together. The real magick is USRP. Satellite receiving and decoding the digital into MPEG while descrambling is nothing new.

USRP (soft radio) is a totally different concept in tuning and demodulation.

Depends on the country

[Sycraft-fu]

In the US it's not legal to have a device that listens in on certian bands, such as cell bands and military frequencies, and other than a few speicifc bands, you need a license for any transmitter. So the transmission components are almost certianly illegal in the US, at least to use. The reciever components, it depends on the range, and if the have holes where they should for given disallowed frequencies.

Now this applies to the US one, other countries do not necessairly have an FCC equivilant that regulates such things.

Re:Depends on the country

[Anonymous Coward]

The reciever components, it depends on the range, and if the have holes where they should for given disallowed frequencies.

From http://www.privacyrights.org/fs/fs2-wire.htm:

LAWS REGARDING WIRELESS EAVESDROPPING

Is it legal to intercept other people's cordless or cellular phone calls?

The Federal Communications Commission (www.fcc.gov) ruled that as of April 1994 no radio scanners may be manufactured or imported into the U.S. that can pick up frequencies used by cellular telephones, or that can be readily altered to receive such frequencies. (47 CFR Part 15.37(f)) The law rarely deters the determined eavesdropper, however.

The important part is the "readily altered to receive such frequencies." This product seems to receive the entire spectrum by default. I guess you could apply bandpass filters to limit the user, but it would be trivial to bypass those filters.

Re:Depends on the country

[mindriot]

This product seems to receive the entire spectrum by default.

No. The USRP motherboard is capable of handling anything from DC to 2.9 GHz, but you need the matching daughterboards for specific ranges. Daughterboards include:

• BasicRX, 0.1-300 MHz receive
• BasicTX, 0.1-200 MHz transmit
• LFRX, DC-30 MHz receive
• LFTX, DC-30 MHz transmit
• TVRX, 50-860 MHz receive
• DBSRX, 800-2400 MHz receive
• RFX400, 400-500 MHz Transceiver
• RFX900, 800-1000 MHz Transceiver
• RFX1200, 1150-1400 MHz Transceiver
• RFX1800, 1500-2100 MHz Transceiver
• RFX2400, 2250-2900 MHz Transceiver

Also, you obviously need to have the matching antenna to actually receive something useful in a given frequency range.

Now, whether or not receiving particular frequencies is allowed or not will obviously depend on the FCC and similar regulatory organizations (in most, if not all countries, for instance, receiving police radio frquencies is illegal). Maybe the FCC regulation you mentioned is taking things a bit too far... cell phone standards like GSM are encrypted anyway (unless, of course, you go for a man in the middle attack).

As to your FCC quote, I suppose the question is whether being able to buy another daughterboard/antenna means it can be "readily altered to receive such frequencies." With respect to transmitting, the FAQ states that since it's sold as test equipment, you don't need a license. I wonder if the "test equipment" status supersedes that FCC statement as well?

Re:Depends on the country

[KC7JHO]

With an amateur radio license it is still legal to receive police and emergency radio frequencies and under certain circumstances it is legal to transmit on them.

People vs. FCC

[novus ordo]

"It enables everybody to be a broadcaster," he says.

Not quite.

Au contraire

[Anonymous Coward]

Compared with trying to produce this functionality any other way, this is very very cheap. It will get cheaper if there is enough demand.

Software defined radio is really where it's at if you're interested in radio at all. It provides a chance to implement anything in the communications text on real equipment. A lab set of these wouldn't even break the bank. Mere begging, wheedling and pleading should do the trick. I'm very excited.

some misconceptions in the posts

[mdmarkus]

Some people both here and in Wired's comments are concerned with this being used to transmit. Nothing in the article talked ab't transmitting; this is a receive only technology. When they're talking ab't using this for radar, they're doing it passively; using the existing commercial FM transmitters as the basis signal being reflected (for this, i think multiple antennas will be necessary).

Also, so far as i know, in the US, there's no restriction on what frequencies can be listened to. In the UK, i think there's licensing issues, but nothing should restrict this in the US.

Re:some misconceptions in the posts

[mdmarkus]

Ok, reading further (on the USRP FAQ page), i see that they are selling transmitters (and transceivers). They push the legal compliance to the user which might not hold up, but let's see...

Re:some misconceptions in the posts

[elleomea]

Transmission modules are available, the motherboard doesn't have transmission capabilities but many of the daughterboards available for it do.

Re:some misconceptions in the posts

[jrockway]

This is wrong, the GNU Radio software has no trouble transmitting. I believe that an 802.11b card is being worked on, for example.

Sorry... not universal

[modmans2ndcoming]

It can not capture Zero-Point Energy, so it is NOT universal.

Re:Sorry... not universal

[demmer]

and its not a tricorder either.

Re:Sorry... not universal

[Anonymous Coward]

also it can't use a ZPM to power it....

decoding HDTV?

[mackermacker]

Ok, I must be missing here (the details of HDTV were not very specific). Do other people NOT decode HDTV, and is that milestone? Any product by DVICO will also decode HDTV. My Dvico USB unit decodes it. All you need is an antenna. Granted, only local stations are picked up. But it doesnt matter, you can copy everything else too using other methods. Is he referring to cracking the RCE broadcast flag that certain HDTV channels have (INHD/INHD2 in certain areas?). Does my comcast box not already decode HDTV? I guess I don't fully understand the issue. Even if the RCE broadcast flag is set in the HDTV content, you can still plug in a firewire cable (at least in the Motorola/comcast boxes), and output to your workstation, capturing the raw .ts HDTV streams. All the ports are already open (as required by law), just no firmware for the boxes. YOu can even verify the active firewire using the command power-select-select, then going to section 11 and verifying the active ports changed from 0 to 1. Once you have these .ts streams saved, you can output back to your HDTV using DVI if you have it. And doesnt the RCE flag (again, required by law) require you be able to save it at least ONCE (common for pay-per-view on demand). In that case you capture it while it is playing, and you still get it. You don't have to respect the flag, it's up to the client (comcast). If they didn't though, they would loose all their advertising money. However, I don't know why a client on a workstation would need to repsect the broadcast flag. And if you are that interested in saving your HDTV content: http://www.avsforum.com/avs-vb/showthread.php?s=&t hreadid=353608&highlight=windows+xp+firewire

Re:decoding HDTV?

[TheRaven64]

The Slashdot summary was monumentally bad. My first thought on reading it was 'this sounds like the kind of thing you could use with GNU Radio." Clicking on TFA, I discovered GNU Radio was in the article title. Strange how Slashdot, usually GNU-obsessed, would miss that out.

GNU Radio is a pretty amazing piece of software. I attended a talk about it at Linux '05, and was amazed by the capabilities. When they say they are decoding HDTV, they mean that they are doing it in software. All of it. Not just decoding the MPEG-2 streams, but everything this side of the analogue to digital convertor. They are not running it through a decoder box and grabbing it from a FireWire connection, they are capturing the radio signals, converting them into digital signals in hardware and then doing everything else in software.

The basic architecture of GNU Radio is a filter API. Individual filters are written in C++ for performance and then they can be joined together and controlled with Python, making the barrier to entry very low for anyone who wants to tinker with it. Don't be fooled into thinking you need an expensive receiver like the one in TFA to play with it either, it will accept input from a large number of ADCs, including sound cards. You can use it to apply transformations to any digital waveforms.

You can use it to implement something like 802.11 entirely in software, generate telephone dialling tones on your sound card, modulate your voice to sound like a Dalek, decode HDTV signals, or a huge range of other things. It turns your PC into a hugely powerful programmable DSP.

The hardware in TFA is just icing on the cake. As I recall, the specs for a slightly simpler model are available from the GNU Radio site, so you can build one yourself if you have (a lot) more time than money.

Re:decoding HDTV?

[gfilion]

Ok, I must be missing here (the details of HDTV were not very specific). Do other people NOT decode HDTV, and is that milestone? Any product by DVICO will also decode HDTV. My Dvico USB unit decodes it.

The milestone is that it's done entirely with open-source software, instead of a proprietary chip.

Re:decoding HDTV?

[maxume]

The novelty of GNU Radio is that instead of just the HDTV decoder being software, the tuner is too. If the application(TV, fm radio, HDTV, etc) you want falls inside the frequency range your hardware can sample, you can build a software tuner. The novelty of this hardware is that the cheapest prior solution started in the several of thousands -- generalized a/d converters intended for scientific data sampling, like: http://www.atmel.com/dyn/products/devices.asp?fami ly_id=611

Re:decoding HDTV?

[Nocterro]

Does that mean that GNU Radio can be used to bypass HDMI when receiving HDTV signals by never touching HDMI compliant hardware? And if so, how long until it's shut down entirely?

I hear hype...

[SuperBanana]

"Here," he explains, "I'm grabbing FM." "All of it?" I ask. "All of it," he says. I'm suddenly glad the soundcard isn't working.

Not quite- in order to fit the swath of FM radio into that USB2 pipe, it isn't sampling it in any great detail. If you tried to decode one station, it'd most likely sound like a tin can, unless you sampled a narrower slice of the FM band. So don't get too excited. Claiming the motherboard or these devices are "universal" is extremely misleading. You buy modules that transmit or receive on different bands. They're usually pretty wide in frequency spectrum, but they also generally aren't anywhere near as good as dedicated receivers for those bands, and they're not "universal."

Claims of being able to receive GPS are also misleading- you'd be able to decode individual satellites and perhaps obtain a fix within a mile or so, but getting accuracy anywhere near what a $100 handheld GPS unit can do, would require incredible timing accuracy that board just doesn't have. Remember...GPS works by timing how far radio waves w/time signals take to travel...down to about 10 feet in some cases. Think hard about what kind of timing accuracy and precision that requires.

Re:I hear hype...

[David Bengtson]

Sorry, GPS location requirements don't rely on the timing on the board, all of the timing and position is derived from the received signal. You need to be able to receive 3 or more satellites for a fix. There are several folks working on GPS receive applications for the USRP right now.

Dave

Re:I hear hype...

[lowen]

I have two of these personally. At PARI we have four of them. They work. And work well, for radio astronomy.

As to capturing the entire FM band at one fell swoop, I know for a fact that the USRP and a good USB 2.0 High-Speed host can sustain 32MB/s transfers. This becomes an actual sampling rate of 8MS/s in quadrature, which means a full 8MHz band can be sampled at 12 bit precision. The FM band is 107.9-87.9=10MHz wide. At 12 bits, no, you can't get the whole band in. However, the USRP can go 16MS/s at 8 bits (again, in quadrature, which effectively doubles the sample rate), and consume 32MB/s across the USB. Since FM (frequency modulation) doesn't require large dynamic range in terms of bit depth, it is possible that you could get nearly full fidelity audio out of all FM channels simultaneously: but you would need one big honking PC to demodulate in real-time.

As I am a licensed Amateur, I can use this as a transmitter, in the bands and with the modulations to which my license class is allowed. I have the 400-500MHz transciever board; I am of course limited to the 70cm Ham band for transmission, and I of course honor that. It works quite well.

For radio astronomy, I have the DBS_RX board, and it directly tunes several radio astronomy bands, including the Hydrogen line at 1.42GHz. It works quite well for both continuum and spectrum studies, although I still have some bugs (with considerable help for the GNUradio project and other programmers) to work out.

Re:I hear hype...

[lenhap]

You obviously read the article, but did you think to read any details on the actual device? The baseboard/motherboard has a ADC that can capture 10 million samples per second at 12 bits per sample. So doing simple math and ignoring protocol overhead to transmit all 10 million samples would require 12bits per smaple * 10 million samples per second = 120 million bits per second. USB2 has theoretical bandwidth of 480 million bits per second, so the rough back of the envelope calculations would suggest that the full 10 million samples the ADC can capture could be transmitted to the computer over USB2.

So if we assume that the all of the data can get to the computer, could the device grab all of the FM in such a format that it could be "decoded" into normal FM quality audio? Short answer, yes. The daughter cards for the baseboard/motherboard convert the signal down to an IF (intermediate frequency) within the range of the ADC. If you really want to know how IF and all that stuff works, look up FM radio on wikipedia.

What really annoys me is how you try (key word is "try") to explain that this device cannot do GPS. You do NOT need accurate timing to do GPS. Time is part of the GPS solution, so you only need a simple realitively accurate clock. The $100 handheld GPS units don't have anything more accurate than the clock in your pc, which this device would have access to (the clock in your pc, that is). In fact GPS is often used to provide timing for applications like NTP servers. Again you would need one of the daughter cards to convert the GPS signals down to an IF. The actual GPS signal (C/A-Code) is transmitted in the L1 band (1575.42 MHz) which when converted down to an IF could be handled by the ADC in the device. From there you would only need to aquire 4 satelites to get a simple PVT solution (position, velocity, and time). And, FYI, GPS in certain applications and situations can give accuracy to within cm range (mm range if using differential GPS and post processing which this device could do).

So before posting as if you are an expert, look up some stuff on what you are writing...or at least explain that you aren't positive on how everything works but you don't think it could do what it claims. And yes, I actually work doing military GPS for a company and have a BS in EE with a concentration in communications (so I should hopefully know what I am talking about).

Re:I hear hype...

[ChrisA90278]

No, GPS is designed such that no precision timming is needed inside the reciever. The precisionclocks live inside the spacecraft. The spacecraft trans mit digital messages containing only the orbital parameters and the time of day. Recivers only have to look at the low data rate digital messages and compare the time field in each. The reciever then solves a set of equaations and gets location. Solving can take a good deal of time on a low end device so the GPS really tells you where you were a second ago not were you are unless you are not moving. This device was never inteneded as a comercial product the intended market is radio hobbyests who need a "front end" so they can experimant with the software. There are other front end that cost alot less. The bottle neckis always bandwidth. How much of the spectrum can you stuff into a PC?

Re:I hear hype...

[SuperBanana]

And, FYI, GPS in certain applications and situations can give accuracy to within cm range (mm range if using differential GPS and post processing which this device could do).

Not without on-site differential GPS corrections, no...not even on the military band; WAAS at theoretical best gives you about 6 feet. Far as I know the most accurate non-military system is John Deere's private differential system, and it doesn't give anywhere near the accuracy you are talking about.

PS, from Wikipedia. Each satellite repeatedly re-broadcasts the exact time according to its internal atomic clock along with a digital data packet. The data includes the orbital elements of the satellite's precise position, satellite status messages, and an almanac of the approximate position of every other active GPS satellite. The almanac lets GPS receivers use data from the strongest satellite signal to locate other satellites.
Receivers
GPS receivers calculate their current position (latitude, longitude, elevation), and the precise time, using the process of trilateration. This involves measuring the distance to at least four satellites by comparing the satellites' coded time signal (PRN Code) transmissions. The receiver calculates the orbit of each satellite based on information encoded in their radio signals, and measures the distance to each satellite, called a pseudorange, based on the time delay from when the satellite signals were sent until they were received.
*SNIP
One complication is that GPS receivers do not have atomic clocks, so the precise time is not known when the signals arrive. Fortunately, even the relatively simple clock within the receiver provides an accurate comparison of the timing of the signals from the different satellites. The receiver is able to determine exactly when the signals were received by adjusting its internal clock (and therefore the spheres' radii) so that the spheres intersect near one point.

So, sorry Dr. Dickhead Nitpicker EE, if I didn't get it EXACTLY right, but looks like I came pretty goddamn close.

Re:I hear hype...

[Anonymous Coward]

You know - learning to accept your errors graciously could go a long way.

What you posted from wikipedia correlates very well the parent (and reality) - and absymally with your explanation. But then, maybe you don't even know what you're talking about well enough to understand that.

(another GPS engineer)

Re:I hear hype...

[mrcaseyj]

If my understanding is correct, GPS receivers need extreme quality crystals. My bottom of the line GPS that doesn't even do WAAS has a somewhat expensive temperature compensated crystal oscillator (TCXO). TCXOs didn't even used to be good enough, so they used oven compensated crystals (OCXO) to maintain the temperature. The receivers get the time from the satellites but they still seem to need extreme quality crystalls. Surprisingly, I think the problem is the minuscule variation in crystal frequency as a result of the small temperature changes that happen over just the seconds needed to complete a measurement. That's the kind of insane precision we're talking about.

No restrictions in the US?

[Anonymous Coward]

Think again...
http://www.afn.org/~afn09444/scanlaws/
Let freedom ring...

Well

[Anonymous Coward]

People, keep in mind, this is a dangerous tool. A simple software patch could make this into a GPS jammer or satellite distress beacon spoofer. Or, it could jam cell phones, emergency frequencies, listen in on cell phone conversations (I read something about the encryption being cracked years ago?), ignore the HDTV broadcast flag, allow you to emulate someone else's cell phone, send the cops away on another call by jamming or overriding dispatch, jam 802.1 networks or allow you to wardrive from extreme distances (since the tranceiver is NOT subject to the power limitations of standard network cards, combined with the right antennae you could break into any network within line of sight). You could start a pirate HDTV station on an unused piece of spectrum that broadcasts 100% porn.

Phrasing it that way, this sounds kind of cool, but you bet your ass they will make these illegal

Re:Well

[Loconut1389]

No patch required, just the right code- the board merely takes a stream of values and transmits them.

As for making it illegal, the board is considered test equipment and even the transmit boards only have a minimal power output (100 mw or less)- you'd need to buy or build an amplifier for the right frequency get the cables to hook it up, and build an appropriate antenna.

This is still not a device that just any idiot can cobble together something that does thoes things- it's not necessarily extremely difficult, but still requires effort.

There are simpler ways to jam transmissions without such complex equipment.

I don't think the government has much to worry about from these boards and the FCC is quite good at noticing and finding rogue signals that cause interference.

Re:Well

[lowen]

GNUradio, both in the software and hardware side, is designed to be an experimenter's kit and test equipment. I'm working on using one of mine as a time-domain reflectometer; another use is as a vector network analyzer; it's just a programmable signal generator and detector set with four channels. You can get various RF modules just like with, say, a piece of Agilent test gear. You could take a programmable signal generator with an external modulation input and do the same.

I use mine all the time as a tunable oscilloscope, spectrum analyzer, and signal generator for testing.

That is, after all, what the USRP is sold as.

The beauty is that once you have the Universal Software Radio Peripheral hooked up, you can plumb the software modules (they are actually called 'blocks' in GNUradio-parlance) to make any sort of processing chain you'd like. It is a beautiful and workable design.

Re:Well

[Etcetera]

Extremely dangerous... Pirate radio is one thing -- but anyone who's studied enough to know what they're doing is usually respectful enough to be a "good broadcaster", even if they don't have a permit (meaning doing what they can to avoid interference, clean signals, etc...)

Imagine script kiddies getting a hold of these devices and sticking them near an airport. Furthermore, all the bitching about privacy you see here at Slashdot might take on a new meaning once anyone out there is listening in on your cellphone conversations (again).

Re:Well

[Thomas Shaddack]

Imagine script kiddies getting a hold of these devices and sticking them near an airport.

So there'll be minor issues for a while, the navg systems are more redundant than you think. Then the same radio tech gets deployed on the airplanes themselves, and together with cryptographically signed signals and phased array antennas the airport/aircraft equipment can easily discriminate between legitimate and illegitimate signals. Where's the problem?

Furthermore, all the bitching about privacy you see here at Slashdot might take on a new meaning once anyone out there is listening in on your cellphone conversations (again).

NSA already does. Together with anybody who can hack up a diode downconverter or mail-order a scanner from Canada.

This may at least be a good reason for the sheeple to demand less insecure telephones; the "too complicated" vendors' cop-out from the Analog Age doesn't apply anymore.

Thank You

[Tsen Wrath]

Thank you Matt Ettus and Eric Blossom.. you have taken stalking to all new levels. I am eternally grateful.

Miserable future...

[Ryz0r]

From the Article:

"Ettus paints a picture of radio bringing about a many-to-many revolution, like blogging, but for a wider segment of the world. "It enables everybody to be a broadcaster," he says."

I think i prefer Orwell's future! Imagine turning your USRP enabled TV on and catching this:

"And Now, Coming To You Live From Sophie's Bedroom, Iiiiiiiiiiiiiiiiiiiit's: FEED THE CAT!!
Tomorrow, Tune In For EmoJake's Visual Guide: Getting the Most Attention from Cutting Yourself with the Least Amount of Pain!"

With my $550

[slashnik]

I'd by a Garmin GPS, a Yupiteru scanner and a decent FM/LW/SW radio (not Sony: DRM)

Similar package for less than $600 complete

[ps_inkling]

The ICOM PCR1500 (Japanese) already receives everything from DC to 1.3GHz (minus analog cell frequencies, unless you're a government user). No additional modules required, and uses USB and fairly open software controls.

Or, for even cheaper ($350), Ten-Tec's RX-320D, with digital radio. Everything from DC to 30MHz (shortwave).

I've never used any of them, your milage may vary, etc.

Re:Similar package for less than $600 complete

[mrbill]

I had one of the prior version, the PCR-1000 (used 9pin serial instead of USB). Awesome little receiver.

So what?

[Slithe]

IP Adresses can be changed, and MAC addresses can be spoofed. If you are TRULY paranoid, connect to a random Access Point with a spoofed MAC address and talk using an encrypted VOIP connection. Simple, easy, and cheap (you can buy a laptop, microphone, and wifi card for less than the cost of the USRP motherboard.

Good for DXing?

[elgee]

I will have to look at this closely to see if it might be sensitive engough to qualify as a good shortwave receiver. It would be cool to control it from my computer. I know some top end receivers already offer that option, but this is affordable.

MythUSRP

[Flimzy]

I'll buy one as soon as there's a MythTV plugin for it!

The real question-PirateTV.

[Anonymous Coward]

So does DirectTV have a right to privacy then?

Re:The real question-PirateTV.

[Loconut1389]

Yes and no- they have a right to encrypt their signal and we have a right to listen to the encrypted signal- which essentially does no good. Decrypting that signal would be illegal/wrong given the current laws and morals of radio communications- in a perfect world we could line of sight transmit to the intended users specifically and not irradiate everyone else and we could alter the laws to make more sense.

I personally feel we should be able to listen to anything that crosses our space- and decrypt it if we can (or have fun with the challenge of doing so), but not necessarily use whatever service gets decrypted (eg- ok cool, I did it, I can decode DirecTV, next project) and definately not interfere- with the exception of unlicensed bands where interference is more or less necessary.

"the right daughterboards"

[Erandir]

Be careful of that seemingly innocuous qualification: "with the right software and daughterboards"... both imply serious limitations to the technology.

Firstly, the "right" software: Even with a reasonably fast processor (say 3 GHz) today, you are typically only be able to process, at most, a few million samples per second -- especially if you are performing complicated modulation/demodulation, coding/decoding, filtering and protocol processing. Each sample may require substantial computation, and that limits the number of samples you can process per second. That, in its turn, affects the bandwidth that a processor can address (i.e. how wide a part of the radio spectrum you can "see" at any one time).

Secondly, the "right" daughterboards: To be able to address a wide bandwidth, we require digital-to-analog and analog-to-digital converters with high sampling rates. These are limited by the state of the art in signal conversion technology -- typically a couple of million samples per second if we want a reasonable number of bits per sample (at a reasonable price). Push it beyond that, and we have to be happy with fewer bits per sample (may 10 or 8 bits). This introduces noisiness to the signals being transmitted or received, degrading the fidelity of the software-defined radio.

Also, a daugterboard usually has some form of signal translation hardware ("mixers") to translate the low-frequency signals that computers can generate to and from the higher parts of the radio spectrum. Although broadband mixers are available, they need tunable oscillators (reference frequencies), and these tend to be limited to narrower parts of the spectrum. Also, analogue filters, amplifiers and antennas (which all form part of a typical software radio front-end), usually are limited to specific ranges of the radio spectrum.

In short, software radio daughterboards tend to be fairly application-specific (or at least spectrum-specific). We can do a lot of things in software, but a "universal" software radio needs a lot of hardware swapping. I think that makes it a bit less "universal". It might also push the cost of a truly multi-purpose system quite a bit beyond $550.

But I'm glad to see this technology receiving such mainstream attention, and I applaud the efforts of the designers. I just think that TFA (and the post) could maybe be a bit less sensasionalist.

And yes, IAASDRE.

G-J

Re:"the right daughterboards"

[lowen]

The Right Software: The GNUradio stack.
The Right Duaghterboards: The USRP is outfitted with two Analog Devices AS9862 MxFE chips, each possessing two 64MS/s 12 bit ADC's, two 128MS/s 14 bit DAC's, and assorted auxiliary ADC's and DAC's for things like AGC.

The daughterboards themselves are just RF frontends. The DBS_RX, for instance, uses a Maxim satellite receiver chip that quadrature downconverts from the RF directly to plus and minus baseband. One MxFE can do quadrature, and is a good match to the single RF input I/Q output DBS_RX board to 900-2400MHz receive.

The USRP gets this 64MS/s bitstream munged down to a manageable size by use of an Altera Cyclone FPGA, which, using CIC and half-band filters implemented with CORDIC, bitmashes things down to a rate that will fit over the USB 2.0 High-speed interface.

Re:"the right daughterboards"

[Erandir]

Sure -- don't get me wrong. I'm not arguing that good techniques exist for both software signal processing and for analog front-ends: I'm just emphasising the point that these techniques are limited by (a) the computational power of the CPU, and (b) the frequency limitations of the hardware. It sounds as if the daughterboards come with state-of-the-art converters -- this comes at a price. Also don't neglect the fact that, the broader the part of the spectrum you want to receive, the more dynamic loss you have. Roughly, each time you double the frequency of the band you want to address, you lose one bit of precision, because different frequencies "add together" to swallow up your available dynamic range. How far are you willing to push the bandwidth before this dynamic loss becomes unacceptable?

It's great to hear that the front-end uses quadrature conversion! (Well, not that I think this wide range of addressable frequencies would have been possible using any other technology :) But this also comes with a bit of a price -- quadrature converters have inaccuracies of their own, usually introducing spurious components in the transmitted/received signal. There are ways to address this, but, AFAIK the efficient techniques are not quite mainstream yet.

CIC is a great downsampling technique, and an FPGA implementation a very efficient way of getting things done in real time. Once again, kudos to the designers: This really sounds like an excellent SDR implementation. I'm just saying "remember, it still has some limitations".

Even if USB 2.0 can crunch 480 Mbps (let's say 48 MS/s), the "managable size" that fits over USB 2.0 may still be a far cry from the "managable rate" that the processor can handle doing, say OFDM demodulation. I stand by my point that the processor's capabilities represent the fundamental limitation to the bandwidth that such a device can handle. Fortunately, Moore's law plays in our favor here: If we develop the technology now, capable hardware will arrive -- eventually.

Things are a bit more difficult at the antenna side. Even the smartest of antennas cannot cover all the interesting bits of spectrum from LF to V-band. At this point in time, some hardware swapping to accomodate specific applications seems inevitable.

I want to emphasize again: I love what these guys are doing, and the way that they're doing it. I just want the bounds of our current art to be clearly demarcated.

G-J

Re:"the right daughterboards"

[lowen]

Certainly all things have limitations. But, catch this:
1.) The hardware design (schematics, layouts, etc) are OPEN;
2.) The FPGA Verilog code is OPEN;
3.) The software is GPL.

As to the computational power of the CPU, I'm thinking an FPGA coprocessor could be used to great effect; something like a DRC coprocessor in a socket 940 (Opteron socket): see http://www.drccomputer.com/pages/modules.html for details. Run the correlation and other functions in the FPGA and offload the grunt work of the algorithm to the hardware logic you blow into the FPGA.

In my own experience, a continuum analysis (power spectrum integration using cascaded FIR filters) and a simultaneous FFT can run with 65% of a 3GHz Xeon, with all the X11 overhead taking 50% of a second 3GHz Xeon. The hard part is sustaining continuous 32MB/s writes over a period of hours (I have a Dell 2850 here with hardware RAID that can do 150MB/s writes in theory; in practice even that can skip samples). And that is using the GNUradio Python framework; tuned C would likely be less taxing on the CPU.

In contrast, we are working on other projects that are running an order or two of magnitude higher sample rates; one with be sampling 12 channels at 1.5GS/s 8 bits and performing a correlation for probing the interstellar medium using compact extragalactic sources at 2.1 and 8.5GHz. That will require the equivalent of an 800GHz Xeon; only hardware FPGA correlation is anywhere close to fast enough, and even then we're talking $10K high end Xilinx Virtex 4's.

Coprocessing FPGA's are basically required for real-time processing of this sort.

Re:"the right daughterboards"

[yppiz]

The parent poster writes: Be careful of that seemingly innocuous qualification: "with the right software and daughterboards"... both imply serious limitations to the technology....Even with a reasonably fast processor (say 3 GHz) today, you are typically only be able to process, at most, a few million samples per second -- especially if you are performing complicated modulation/demodulation, coding/decoding, filtering and protocol processing. Each sample may require substantial computation, and that limits the number of samples you can process per second. That, in its turn, affects the bandwidth that a processor can address (i.e. how wide a part of the radio spectrum you can "see" at any one time).

I'll bet it's not long before the USRP/GnuRadio people hook up with the graphics card as a compute engine folks. Graphics cards are well suited for high-speed signal processing, and would give you the ability to process high-bandwidth signals in realtime even on an ordinary PC.

GPGPU: General-Purpose computation on GPUs
The FFT on a GPU
GPU-FFTlib - Graphics Card based Implementation of the Fast Fourier Transform

--Pat

WinRadio

[femto]

Surely these guys should give acknowledgement to WinRadio? I first played with one of these around 1995. That particular model was a PCI card able to receive from close to DC through to 3GHz.

Re:WinRadio

[suwain_2]

How well do these cards handle noise from the computer? For quite some time now, I've wanted to put a handful of cards into a machine and set up a 'scanner' that would log everything to MP3 files. My concern is that every computer I've ever owned has spewed noise over various portions of the spectrum; I can only imagine what would happen if I put it inside a computer. Or are the cards really well-shielded somehow? (And for that matter, are they worth the money? I seem to recall them being very expensive.)

Re:WinRadio

[westlake]

How well do these cards handle noise from the computer? And for that matter, are they worth the money? I seem to recall them being very expensive.

WinRadio is available as internal PCI and external USB devices. Prices start at $500 US for general-coverage shortwave. Winradio Receivers

Re:WinRadio

[stienman]

Winradio seems to have a max IF of 15kHz. Far, far too small to do anything with TV, much less GPS and other fun things. Perhaps there are models I didn't see (very brief visit).

Software defined radio is nothing new. What's new is that there are more hands in the pot - more people trying to do cheaper generalized stuff with it, as opposed to bog standard radio (voice, CW, etc) communication, and putting the hardware together in such a state that software developers can hack at it without any electronics knowledge.

You've no doubt noticed the general trend of cheapness. It's cheap to make a programmer work hard and develop a feature so that you can reduce the hardware by 1 chip and save millions in the margin. Further, sofware can reconfigure itself much more easily, quickly, and cheaply.

So winradio is as important as all those other "generic reciever computer radios" but this is different and for many applications more powerful.

-Adam

Re:WinRadio

[Abalamahalamatandra]

I used to have a WinRadio, I think it was the 2000 version, in an old Pentium II/233 machine, and it performed quite well and didn't pick up much of anything for hash from the computer, amazingly. The actual radio electronics are very well-shielded on the board, and then it's just a matter of getting the antenna away a little. Actually, though, I got good results with just the long-wire that came with it.

They did recommend at the time that if your BIOS had a setting to ramdomly vary the clock frequency, it was a good idea to turn that on, because then any noise it may pick up will be spread widely and won't interfere with a given signal.

Re:WinRadio

[rfmobile]

No ... the original WR1000 was largely an analog radio. That's not SDR. The real novelty of the original WinRadio models was computer control - tune to a particular frequency - check received signal strength - select mode like AM vs. FM or SSB. You could write software to do automated sweeps of spectrum and log the results but the actual signal path was mostly analog.

One more thing - the PC internal version was an ISA card - NOT PCI.

WinRadio finally introduced a PCI version about a month ago (not ten years ago).

-rfmobile

Re:WinRadio

[Anonymous Coward]

Thanks for the clarification.

What this is and what this isn't

[AB3A]

This is a huge step forward for computer assisted modulation techniques and wide band scanning. However, I should point out one very important limitation: Dynamic Range.

For those of you who are too lazy, read this.

Now let me point out that while the A/D converter is fast, it only has 12 bits. This will give you about 72 dB of dynamic range. Modern reciever design can yeild dynamic ranges of 100 dB or better (depending on how you measure it). Some day we'll get this performace from 16 bit A/D converters. When that happens, expect the designs of radio to change to software over hardware.

This is the trade off for building a reciever of this sort. There is no free lunch folks...

Re:What this is and what this isn't

[John Miles]

16-bit, 100-megasample+ ADCs are already on the market, actually. The current USRP design is a couple of years old; I'd expect them to upgrade their ADCs pretty soon if they haven't already.

Re:What this is and what this isn't

[GreyKnight]

However, it should be pointed out that the number of bits in the ADC aren't necessarily the limit on the dynamic range of the radio; by putting a variable gain amplifier coupled with an automatic gain control upstream of the A/D, I believe you can improve the dynamic range of the system somewhat.

Re:What this is and what this isn't

[lowen]

With proper design in the decimator, a sigma-delta technique could be used to synthesize extra bits digitally during decimation. This is fairly common; that's how modern CD players get away with 1 bit digital to analog converters, by vastly oversampling and using sigma-delta techniques (along with other; I have the references, but they're at work, and I'm at home). Analog Device's mixed signal handbook lists a few of these techniques. So it is possible, after decimation and digital processing, to synthesize a 16 bit conversion from a 12 bit converter, as long as you vastly oversample the 12 bit converter.

Incidentally, the effective limit is 24 bits; beyond 24 bits at standard +4dBu levels the least significant bit's voltage is below the Johnson noise at room temperature over the audio bandpass; see the Johnson-Nyquist page at wikipedia for an overview.

Re:What this is and what this isn't

[r00t]

So add a cooler.

Erm... not exactly everything.

[acid06]

From the same link you provided about the ICOM PCR1500: "Incredible coverage is yours with reception from 10 kHz to 3300 MHz (less cellular and minor gaps)."

Also, the real thing about USRP is that all its processing is done in software. This is important from a "freedom" point of view because hardware can be regulated extremely easily by governments. But this situation is not quite true for software (DeCSS anyone?).

In fact, I think they'd never be able to outlaw the USRP motherboard itself but some of the daughterboards could be. But that's the whole point of it: the daughterboards could be home-made if necessary - they're simple enough and just need to capture the radio signals (since the processing is done in software).

timing BETWEEN SIGNALS, nanosecond range

[SuperBanana]

Sorry, GPS location requirements don't rely on the timing on the board, all of the timing and position is derived from the received signal. You need to be able to receive 3 or more satellites for a fix

I don't think you understand how GPS works. Simplifying- a GPS receiver looks at when signals with the same timestamp arrive, and deduces how far it is from each satellite from that. If a signal from Satellite A saying "hey, it's 12:01:05 right NOW arrives a second after a similar signal from Satellite B, then the receiever knows that it is 1 light-second further away from Satellite A than B (this is a gross exaggeration of the scale of time involved.) With 3-4 satellites, you get a position fix.

Modern receivers can track 12-20 satellites at once and get accuracy down to 10 feet or so. There are two things the receiver must do which are timing-related:

1)Figure out what time it -really- is, so it can set an internal chronometer, so it can know the exact distance it is from satellites, versus relative distances

2)Record as exactly as possible when each satellite's particular timestamp came in

Both require -staggering- accuracy that a PC, or your USRP board, are incapable of providing. Clock skew considered perfectly acceptable in a PC is considered monumentally inaccurate in a GPS receiver...and the timing resolution isn't anywhere near good enough either. You're talking about comparing timing in LIGHT FEET, and light takes 1/299,792,458th of a second to travel a meter. It's about one NANOSECOND a foot, so you need resolution exceeding 10nS.

You've got to do a lot of signal processing to ignore spurious signals, as GPS signals love to bounce off some things, and get absorbed readily by others. You've got to have an incredibly low noise, highly sensitive receiver, as GPS is readily absorbed by just about anything, and that includes trees.

The current state of the art is SiRF's SiRF-3 chipset; I've got a Garmin handheld with one, and I can get a 30 foot position lock inside my house, under treecover. I can get a 10 foot lock if I'm outside with enough satellites in view and a WAAS differential signal. I'd -really- like to see you try to beat that.

Re:timing BETWEEN SIGNALS, nanosecond range

[Anonymous Coward]

I don't think you understand how GPS works. Simplifying- a GPS receiver looks at when signals with the same timestamp arrive, and deduces how far it is from each satellite from that. If a signal from Satellite A saying "hey, it's 12:01:05 right NOW arrives a second after a similar signal from Satellite B, then the receiever knows that it is 1 light-second further away from Satellite A than B (this is a gross exaggeration of the scale of time involved.) With 3-4 satellites, you get a position fix.

You are the one who has no clue here. Very few GPS systems work that way, because it requires an atomic clock. Instead, they solve for 4 variables. 3 for position and 1 for time. Any page explaining GPS will tell you this. Look it up yourself.

Re:timing BETWEEN SIGNALS, nanosecond range

[Ruie]

Both require -staggering- accuracy that a PC, or your USRP board, are incapable of providing. Clock skew considered perfectly acceptable in a PC is considered monumentally inaccurate in a GPS receiver...and the timing resolution isn't anywhere near good enough either. You're talking about comparing timing in LIGHT FEET, and light takes 1/299,792,458th of a second to travel a meter. It's about one NANOSECOND a foot, so you need resolution exceeding 10nS.

You've got to do a lot of signal processing to ignore spurious signals, as GPS signals love to bounce off some things, and get absorbed readily by others. You've got to have an incredibly low noise, highly sensitive receiver, as GPS is readily absorbed by just about anything, and that includes trees.

10ns corresponds to 100Mhz frequency. AFAIK USRP sampling rate is around 16 Mhz (someone knowledgeable please correct me!) however this is provided by crystal oscillator so it is stable to at least 1/10 of the cycle. In fact, it should be way better or the phase noise in the ADC will be very noticeable.

So instead of using PC clock one can simply use the sample number from USRP as a timing source.

Re:timing BETWEEN SIGNALS, nanosecond range

[David Bengtson]

Sorry, I know exactly how GPS works, I'm working on a GPS receiver board for Gnu Radio (www.keystoneradio.com).

You don't need absolute timestamps on each sample to get distance. The timing is encoded in the PN sequence in the transmission from each satellite. Also included in the transmission from each satellite is the satellite orbit information and the exact time that the GPS system uses. First, you receive 1 satellite, and then set your GPS clock to the system clock. Once your handheld GPS is set to the system clock, you can figure out how far you are away from the satellite by determining time of flight from the satellite to the handheld (You know the PN sequence, and you know the time. You can figure out the time that you received the signal, and then you can determine the distance)

Once you know the distance from 3 satellites, then you know you are in 1 of 2 locations. If you further assume that you are reasonably close to the earth's surface, then you knock off one of the possible locations. More satellites will give you a better estimation by giving you more position estimates to average out.

As far as the signal processing, the GPS signal comes in to the antenna pretty close to the thermal noise floor, and so it's a bit tough to receive. Because it's a direct sequence spread spectrum system, you get 43 dB of processing gain from the de-correllators which helps significantly. Multi-path isn't really to much of an issue because the signal is primarly from overhead. Absorbtion is more of an issue, and is something that Garmin/SiFR etc spend a lot of time dealing with.

As far as beating the current state of the art in GPS receive algorith's with a half dozen guys working in their basement, probably not. As an educational thing, it's pretty useful.

Dave

Re:timing BETWEEN SIGNALS, nanosecond range

[aluminum_geek]

My understand of GPS and your understanding of GPS don't jive.

As I understand it, the entire reason that the GPS doesn't need it's own atomic clock is because it takes an extra measurement in order to ignore the fact that it doesn't really know what time it is. Thats why GPS needs 4 satellites and not 3. In this case, it isn't important to preserve the ABSOLUTE time a signal is received, only the RELATIVE time a signal was received. So long as I know the difference between clock signals I'm fine.

Now, this doesn't help me if I don't know exactly how long the difference is between the clock skew. Because of the analong to digital conversion, I can basically say "The signals are skewed by 200 samples" and not know an accurate conversion from samples to time. However, I know the precise LENGTH (in time) of the message being sent from the satellite. Using this I can correctly determine the "real" sample rate. While you are correct that clock skew is crazy and quartz isn't accuate enough, they don't have to be accurate, they only have to be consistentl and only for as long as it takes to capture the signal.

Re:timing BETWEEN SIGNALS, nanosecond range

[jimmyfergus]

I don't think you understand how GPS works. Simplifying- a GPS receiver looks at when signals with the same timestamp arrive, and deduces how far it is from each satellite from that.

I don't think you understand how a GPS receiver works. It doesn't work out how long the signal took to arrive from a satellite, it works out the difference in the time it took to come from one satellite, from the time it took to come from another. Very different things. You don't need 3 satellites, you need 4, because you are working out your 3D position, plus time.

Read lenhap's earlier response. He knows what he's talking about.

Your points 1 & 2 are just made-up. Accurate time is one of the unknowns that is solved by the calculation, but is not used to make the calculation. Otherwise they'd need atomic clocks in GPS receivers.

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[account_deleted]

Comment removed based on user account deletion

$550 is expensive

[Kuukai]

With prices starting at just $550 this new toy is accessible by most anyone.

So the PS3, which is an actual toy mind you, is "prohibitively expensive", while an esoteric piece of hardware only 1 in 10 people would even know how to use is "fun for the whole family, go out and buy one at Walmart"?

No, it doesn't.

[Ungrounded Lightning]

It makes sense to license transmitters. The EM spectrum of useful radio frequencies has finite bandwidth, and we must have some plan for use so that the most people can get the most benefit out of it.

No, it doesn't.

It makes sense to license OPERATION of transmitters and/or the people who operate them.

Licensing type-approved transmitters, which are crippled so they are unable to violate the rules, is a shortcut to create added utility. Building adherence of the rules into the device allows it to be operated in a rule-abiding way by people who have no special training or licensing.

It is NOT a general case solution.

Sony told you so

[llZENll]

The final puzzle piece in in place. Run this software on the CELL processor and have a radio that can receive and decode anything. Oh wait, that means a $5 radio will now be $300, oh well...

Seriously though, this is an awesome idea, its like the internet 20 years ago, or the personal computer 50 years ago. 100 years from everything will be the same exact microscopic chip running specialized software, from trans dimensional warp drives to an automated bionic eyelash.

America's benchmark for Taxation without Represent

[xski]

DC isn't a state, its a federal district. If you're silly enough to live there as a disenfranchised citizen, thats your choice. Don't like it? Move to a real state that has (so-called) 'constitutional guarantees'.

See US Constitution, near the end of article 8: (Powers of Congress)

To exercise exclusive Legislation in all Cases whatsoever, over such District (not exceeding ten Miles square) as may, by Cession of particular States, and the acceptance of Congress, become the Seat of the Government of the United States, and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings.

IOW, DC was not and is not one of the 'several sovereign states', its purely federal land and Congress has exclusive jurisdiction on federal land.

So the real question is.... All of DC really fits in 10 miles square? Wow.

Better ban transistors and wire then

[EmbeddedJanitor]

You can make an RF jammer with anything thet emits RF. A few simple components from Radio Shack...

Receive all frequencies from DC to a few GHz, $972

[Anonymous Coward]

Receive all frequencies from DC to a few GHz, $972.

sniffing 433 MHz ?

[thechuckbenz]

Granted, I could use this to sniff the 433 MHz signal from the ultrasound sensor in my driveway that tells me when someone drives up, or to pickup the signal from my wireless themometer, BUT, is there a cheaper way to get either of those signals to a PC ?

Eric, what happened at Starium?

[Anonymous Coward]

I'm not sure how many people are aware, but Eric Blossom was heavily involved in a company called Starium that made some super-cool telephone voice encryptor boxes a few years ago. It seemed like it was in beta or "coming soon" for a long time and then the website and company disapeared. What happened? It seemed like such a cool product.

Btw, this radio product also seems very cool. I'll have to get one or two before they become illegal.

Open Source Radio Astronom

[lowen]

Grab a CVS checkout of GNUradio (see http://www.gnu.org/software/gnuradio/ for the homepage, and http://cvs.savannah.gnu.org/viewcvs/gnuradio/ for the browseable CVS on GNU.ORG), and be sure to grab gr-radio-astronomy module.

1 satellite should do

[r00t]

You can take multiple measurements and use the Doppler shift.

One measurement of the carrier frequency locates you on a cone whose axis is along the direction of satellite's travel.

A second measurement should locate you on a curve which I believe to be a hyperbola. (the axis of travel has changed)

A third measurement locates you on a point.

If you can pick up quasars, the Earth's rotation should eliminate any need for satellites.

BS

[lamp540]

Software radios, while great in concept are not real yet. Notice the mention in TFA about "daughterboards" and how that is convienently forgotten. For every small bit of spectrum you will need a different "daughterboard" to access it. These "software radios" are nothing more than 100 year old superhetrodynes w/ slightly different cores.

Did this many years ago....

[hughk]

I was a software engineer on a GPS project for aircraft about 10+ years ago. After an RF front end, the signal was brought into a DSP and slow (by modern standards) processor combination. The software wasn't rocket science and the signal recovery just used the special coding embedded in the GPS signal for recovery.

What this needs is an RFID implementation

[EMIce]

With all the privacy concerns surrounding RFID, it would be nice to have an RFID scanner that covers more than the dinky 125Khz-ish range that you see used in most hobby kits for home automation. Some kits support 13.56Mhz too, which is what I hear the new passports will use, but there doesn't seem to be much hardware available for the 800-1000Mhz range. Also, what is available isn't as programmable as GNU Radio, which is important for working with RFID tags that use less common or proprietary signalling standards.

The 800-1000Mhz Ultra High Frequency range is important because such tags are currently being used in vehicle tires (@ 915Mhz) and toll booth tags (like ez-pass), and it would be interesting in finding out just what else. They can be read from a distance of a few meters at even 150+ mph speeds.

It's funny this \. article came out today because I was just researching GNU Radio + USRP for this purpose and see that a new transciever daughterboard will be coming out that supports the RFID UHF range. I can't afford it, but hope someone will write the necessary signal processing routines to use RFID with this daughterboard and report back what they find and where.

The link below announces an upcoming 800-1000Mhz transciever daughterboard for the USRP -
http://comsec.com/wiki?UniversalSoftwareRadioPerip heral

Also if someone knows a cheaper than ~$700 way to pull off reading UHF RFID tags, speak up.

"Anyone"

[slapout]

"With prices starting at just $550 this new toy is accessible by most anyone."

I don't think you know what "anyone" means.

Stretch a metaphor

[N_Piper]

There is a Flaw in your logic.
While there is an expected right to privacy I don't have the "Right" To parade areound nude in front of my window and sue people who see me, much the oposite I would get arrested for indecent exposure even if I am in my own "home".
And To stretch the metaphor even more we are talking about a clothing designer who is selling Transparent shirts to large busted women and legislating that we "should not look" because it is "bad" rather than just using a fabric that actually protects privacy.