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."

The real question

[Umbral Blot]

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

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 regulate

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 [ettus.com] 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 [wikipedia.org]).

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 [ettus.com] 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: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: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

[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

[ps_inkling]

The illegal to listen to cellphone frequencies comes from the Newt Gingrich and Clinton [google.com] era. Bah, even before then. Some [interesting-people.org] other [64.233.179.104] bills [cdt.org]. Your congresscritter Billy Tauzin [64.233.179.104] was the original sponsor of the Electronic Communications Privacy Act [wikipedia.org].

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

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

[Detritus]

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

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

[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-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 w

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

[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

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 pas

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 ques

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

[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

[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 an

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

[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

[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 d

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

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, an

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 pun

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

[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

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

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.

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

Ouch $550

[9mm Censor]

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

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

[morgan_greywolf]

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

With my $550

[slashnik]

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

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:

[account_deleted]

Comment removed based on user account deletion

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

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.

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.

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 [ettus.com]

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 ro

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

[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" [daviddarling.info], and VLBI [wikipedia.org] 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?

[sik0fewl]

We could call it... SETI@home!

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

Open Spectrum

[Doc Ruby]

Who's got the rest of the software that combines multiple SW radios with phased arrays of smart antennas [wikipedia.org]? 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 [comsec.com]

NOW I can finally

[EW87]

Stalk Vida Guerra via cell phone...

Sorry... not universal

[modmans2ndcoming]

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

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 [avsforum.com]

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 [atmel.com]

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 transmi

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

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,

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

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

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

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.

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.

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

Similar package for less than $600 complete

[ps_inkling]

The ICOM PCR1500 [universal-radio.com] (Japanese [icom.co.jp]) 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 [tentec.com], 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.

"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 sing

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 [drccomputer.com] for details. Run the correlation and other functions in the FPGA and offload the grunt work of the algorithm to

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

WinRadio

[femto]

Surely these guys should give acknowledgement to WinRadio [winradio.com]? 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 [grove-ent.com]

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 electroni

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

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 [radio-electronics.com].

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

[r00t]

So add a cooler.

Re:

[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"?

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.

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: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.

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 difficu

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...

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 cell