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Software-Defined Radio: the Apple I of Broadcast?

Soulskill posted more than 2 years ago | from the will-it-sell-for-hundreds-of-thousands-in-35-years dept.

Communications 153

benfrog writes "A company called Per Vices has introduced software-defined radio gear that Ars Technica is comparing to the Apple I. Why? Because software radio can broadcast and receive nearly any radio signal on nearly any frequency at the same time, and thus could 'revolutionize wireless.' The Per Vices Phi is one of the first devices aimed at the mass hobbyist market to take advantage of this technology."

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News Release (0)

Anonymous Coward | more than 2 years ago | (#40569065)

gnuradio just wasn't sexy enough, I guess. Not enough like arduino on the tip of everyone's tongue.

Re:News Release (4, Informative)

fuzzyfuzzyfungus (1223518) | more than 2 years ago | (#40569257)

gnuradio just wasn't sexy enough, I guess. Not enough like arduino on the tip of everyone's tongue.

The device [pervices.com] in TFA is a piece of hardware designed to support gnuradio(it might support other things as well; but a gnuradio interface is explicitly mentioned in the device specs).

Gnuradio is just the software side. Traditionally, the USRP has been the peripheral of choice. Not cheap; but configurable for a wide range of frequencies and probably the most mature. A sound card(with appropriate external circuitry bringing things down to audio frequencies, of course) is also an option, and certain flavors of DVB TV receiver dongles are the new hotness in the cheap seats.

This "Phi" device lacks some of the versatility of the classier USRP gear; but it is cheaper and offers a very fast interface to the host computer...

Unlike 'Arduino', where the term refers more or less interchangeably to both the software development environment and to a variety of atmega-based microcontroller boards, Gnuradio is just the software side. There is no 'gnuradio' hardware per se, as there is with Arduino. The USRP is probably the closest to being that; but it is pricey enough to be out of the hands of a great many hobbyists.

Re:News Release (1)

ceoyoyo (59147) | more than 2 years ago | (#40569667)

You can get start playing with Arduino for about $25. Less if you can program your own microcontrollers. GNURadio has so far been a software solution with no, or very expensive, hardware to go with it. Not that the Phi changes that, but it's a step in the right direction.

When you can buy a GNURadio setup, including hardware, for under $100, then it'll take off. When it gets down to $25 it will be as popular as Arduino.

Re:News Release (5, Informative)

fuzzyfuzzyfungus (1223518) | more than 2 years ago | (#40570237)

It's receive only, and the quality isn't magic by any means; but you can get an RTL2832-based DVB-T dongle for ~$20 and be on your merry way [osmocom.org] .

(And, indeed, this does seem to have spurred greater interest among people who weren't in for a USRP; but were interested. The fact that SDR involves substantially more nontrivial math than many arduino projects probably limits the mass appeal some, though.)

gnu radio (-1)

Anonymous Coward | more than 2 years ago | (#40569069)

No love for gnu huh. Big surprise considering how much anti-gnu propaganda there is these days.

GNU Radio needs hardware behind it (2)

tepples (727027) | more than 2 years ago | (#40569277)

The article mentions GNU Radio, saying that the hardware used with GNU Radio during the "broadcast flag" debate couldn't capture more than 0.1 MHz of spectrum.

Re:GNU Radio needs hardware behind it (1)

Man On Pink Corner (1089867) | more than 2 years ago | (#40570173)

The USRP1 used a USB 2.0 high-speed interface (Cypress FX2), and it could certainly downconvert at a wider bandwidth than 100 kHz. It would have had to, in order to demodulate ATSC.

I don't know where that line in the article came from. Reporters making up random stuff as usual, I suppose.

Re:gnu radio (4, Insightful)

Anonymous Coward | more than 2 years ago | (#40569311)

I don't know why the sockpuppets are badmouthing the GNU so loudly lately. That ship has sailed. They won. Free(as in freedom) software is legitimate, is a legitimate business model, and is eating the lunch of commercial software in many arenas while chipping away at others. Even the BSDers with their doublespeak about the GPL being "less free" amount to little more than a gigantic pile of butthurt. Maybe you could have made that argument a decade ago, but history has also vindicated the FSF here too.

The FSF and Stallman are like.. Socrates. Principled and unwavering, uncomfortably correct. Their detractors have little recourse but to badmouth them. (Haha communisim, haha dirty bearded hippy.)

Re:gnu radio (1)

englishknnigits (1568303) | more than 2 years ago | (#40570423)

People like bad mouthing Stallman (and, unfortunately, by association GNU/FSF) because he is an arrogant, condescending, overly confrontational, sexist, hygienically inept, eye sore of a man (I'm sure I missed about 10 more glaringly obvious, negative attributes). That doesn't make him wrong or FSF a bad thing but it does make him an easy target for bad mouthing. He is the type of man you want in the background of a movement, locked away in a server room, trying to push the movement forward. He is not the type of man you want to be front facing for any cause. It is just asking for ridicule and derision (deserved or not).

Re:gnu radio (0)

Anonymous Coward | more than 2 years ago | (#40571463)

So he has Assburger's?

Re:gnu radio (1)

lister king of smeg (2481612) | more than 2 years ago | (#40572001)

(I'm sure I missed about 10 more glaringly obvious, negative attributes).

you forgot; he is fine with pedophilia and approves of necrophilia, and bestiality, insest, prostitution, just to name a few, he is paranoid about the use of cellphones as tracking devices and espionage tools, oh and he incredibly jealous of tordvalas and linux.

Pirate radio? (0)

Anonymous Coward | more than 2 years ago | (#40569107)

Is this legal?

Re:Pirate radio? (0)

Anonymous Coward | more than 2 years ago | (#40569169)

Uh, wouldn't that depend on what bands you transmit on, what license you may or may not hold, and what the regulations have to say about it?

Re:Pirate radio? (0)

Anonymous Coward | more than 2 years ago | (#40569199)

Shhh...don't inform the RIAA/MPAA

Re:Pirate radio? (2)

ewanm89 (1052822) | more than 2 years ago | (#40569289)

This is only legal to Amateur radio operators I believe, as it will not be vetted by the FCC/Ofcom... to broadcast only on the allowed part of the spectrum. From a Ham operators point of view, it's not much difference than a full HF/VHF rig, or a USRP with every possible daughter board installed. The big change is that it's all on one card and it uses PCI-Express for the interface to to the computer.

The whole this will stop the FCC having so much control over the spectrum is totally wrong. They'll have as much control as they currently do which is they can shut down any transmitter in the US if it's not following the licensing terms they set out.

Re:Pirate radio? (2)

Iceykitsune (1059892) | more than 2 years ago | (#40569527)

This is a RECEIVER ONLY! The FCC has said that anyone can listen on any frequency.

Re:Pirate radio? (1)

Ellis D. Tripp (755736) | more than 2 years ago | (#40569663)

Then why are analog cell phone frequency bands blocked on scanners?

Re:Pirate radio? (3, Insightful)

zippthorne (748122) | more than 2 years ago | (#40570945)

Cell company lobbyists and congress drones apparently thought that you can keep the radio communication equivalent of shouting across a quiet room private by, instead of encrypting the communication, passing laws that make it illegal to notice.

I'm not sure that the FCC or ITU had any part in it, however it seems likely that at least ITU would have been involved....

The remaining question is whether we'll see the law rolled back now that it's been obviated by encryption (or at least CDMA spread spectrum), and is so obviously useless - the only way to detect if someone is listing is to yourself be listening in enough places to measure the shadow created by their receiving equipment or the extremely low-power emission of interference frequencies, assuming that they're using that method of demodulation, equipment capable of receiving the old AM cell phone transmissions can be made in an afternoon using readily available components.

It's an FCC regulation, alright.... (1)

Ellis D. Tripp (755736) | more than 2 years ago | (#40571457)

[url]http://www.gpo.gov/fdsys/pkg/CFR-2010-title47-vol1/xml/CFR-2010-title47-vol1-sec15-121.xml[/url]

Re:Pirate radio? (1)

SealBeater (143912) | more than 2 years ago | (#40569691)

Hmm, not quite as sexy if you can't transmit.

Re:Pirate radio? (4, Informative)

jiriw (444695) | more than 2 years ago | (#40570843)

Technical Specifications and Support [pervices.com] :

Dual channel, 16 bit, 250 MSPS DAC

Nope ... RX/TX. If you'd read the article by the way, it should have been clear they wanted a SDR that goes both ways. Of course it doesn't really have an amplifier to speak of, so you can't just hook up an antennae to it and expect to work the world. Especially if you want to output multiple signals in multiple bands, as mentioned in the article, things can get very hairy at the transmission end. By the way, good, distortion free, broadband amplifiers aren't cheap as well and come with their own set of problems.

The idea might be nice, an 'open source' spectrum, and for the receiving end it's all fine and dandy. I'm not a proponent, of security through obfuscation/obscurity, so regulation of waves receiving: Governments, just grow up!

But even at low power conditions, for certain frequencies, you don't want to have transmission capabilities in the wrong hands (read: someone who hasn't at least got a a HAM Radio license. A degree in Electronics, Electromechanics, Physics might suffice as well... if it has covered the correct subjects). Things can turn out very nasty even at low power situations. Things like GPS will stop working, or other satellite signals jammed. Many satellites only transmit at an order of 10-100 watts. The amount of signal left when received on earth is miniscule. A little more power and things like Wifi and RC toys/remote controlls/bluetooth will be affected. Digital broadcasting is next I think... including mobile phones and portophone systems there isn't nearly as much robustness in there as there was with the old analogue signals... As they digitized the signals, they could cut bandwith and power requirements... Nice for energy savings and miniaturization of systems but it does mean it can be jammed easier, even if there is overhead in the protocol for error correction. Well .. you'll get the picture.

While I agree this sounds like a better deal for radio enthousiasts than the Ettus USRP and I'll be itching to get my hands on one of these, color me sceptic about the whole low power broadband broadcast 4 noobs vibe the Per Vices founders seem to transmit.

73. PG8W.

Eh? (1)

OverlordQ (264228) | more than 2 years ago | (#40569191)

Most significantly, the widespread adoption of software-defined radio hardware could undermine the FCC's control over the electromagnetic spectrum itself.

No, no it wont. The FCC will bring down the banhammer. If you cause issues, they *will* be knocking on your door.

Right now, the FCC largely focuses on limiting the transmission frequencies of radio hardware. But this regulatory approach is likely to work poorly for software-defined radio devices that aren't confined to any specific frequency.

Yes, yes it will. You cause issues, FCC gets complaints, it sends in the goon squad to shut you down.

Re:Eh? (4, Informative)

icebike (68054) | more than 2 years ago | (#40569479)

Not really.
There are large blocks of spectrum already set aside for use of personal radio devices. Just about anything goes in those bandwidths, subject only to power limitations and staying inside of the spectrum block.

The FCC is all for this type of use. The FCC is also fully in favor of reallocation spectrum when the situation and demand changes, which is why analog TV is a thing of the past.

There is precedent for this.

Re:Eh? (0)

Anonymous Coward | more than 2 years ago | (#40572859)

Actually, you are only permitted to operate certified Type 15 devices on ISM bands as per FCC 47 CFR Part 15.5, likewise for PRS UHF transmission, though I can't find the exact regulation that applies to PRS.

So while you could generate type-compliant emissions with the Per Vices Phi, such use would not be considered legal under FCC regulation without additional licensing. Applying for a radio test and measurement laboratory license and installing appropriate RF shielding in your lab would be a sensible course of action. It might also be possible to acquire a field test license.

Re:Eh? (1)

Sponge Bath (413667) | more than 2 years ago | (#40569513)

...they *will* be knocking on your door.

Black van pulls up and discharges a swat team:
[*bing bong*]
Resident: Who's there?
Guy in black body armor: "Pizza man!"

I looked at the Ettus Research hardware for a while with the thought of experimenting, but my life is already saturated with work and tech. Software radio will remain alongside playing the guitar as something cool I wanted to do, but could not squeeze in between /. postings.

Re:Eh? (1)

osu-neko (2604) | more than 2 years ago | (#40569775)

Software radio will remain alongside playing the guitar as something cool I wanted to do, but could not squeeze in between /. postings.

Your priorities... need prioritizing. :p

Re:Eh? (2)

BlueStrat (756137) | more than 2 years ago | (#40569593)

Yes, yes it will. You cause issues, FCC gets complaints, it sends in the goon squad to shut you down.

No, the FCC field operations are a joke. They have been for many years. Budget cuts have all but neutered what little FCC field-monitoring & enforcement that did exist. Many of the monitoring facilities have been shut down or turned into unmanned remote-operated stations.

They've typically got two or three men and one or two tracking vans for a multi-State-wide area. They're kept so busy tracking things like interference to first-responder/aircraft/military/commercial broadcast that most stuff gets a report filed and that's about it.

Strat

Re:Eh? (0)

Anonymous Coward | more than 2 years ago | (#40572897)

Of course, if you fuck with a cellular network or a broadcast operators ST links, they WILL jump in their van/helicopter and track down your transmitter, and when they do, they will file all the documentation with the FCC, then all the FCC agent has to do is serve the warrant.

At least that is how things work in my third-world country (New Zealand). The big networks police their own spectrum, and the MED receive notice of interference and intervene. It would greatly surprise me if the FCC ignored an interference report with complete field testing data.

What we're on the Radio now? (0)

Anonymous Coward | more than 2 years ago | (#40569209)

This... is my voice... on the R-A-D-I-O!

URL to Printable Article? (0)

Anonymous Coward | more than 2 years ago | (#40569211)

Does anybody have an URL to a printable copy of the article? I couldn't find one.

USRP is expensive (4, Informative)

chihowa (366380) | more than 2 years ago | (#40569219)

The USRP is really cool, but stupidly expensive. Some really cool stuff is happening with the RTL2832 based TV dongles, though. These are $20 devices that can be used to receive from ~64-1700 MHz (or DC-30ish with a little tweaking). So far, much of the info is here [reddit.com]

The USRP would be cool if current PCB layouts and schematics were available or if the development effort went to a system that wasn't just making Ettus a profit. A truly open development platform would really benefit the SDR community.

Re:USRP is expensive (1)

SealBeater (143912) | more than 2 years ago | (#40569825)

I have a USRP2 and I agree, the cost is prohibative, but to be fair, some of the SMD parts are as much as $45 bux each, and it's a 8 layer PCB.

Re:USRP is expensive (1)

Anonymous Coward | more than 2 years ago | (#40570681)

Prohibitive?

LIke tbe B100+WBX bundle for $849.00? That's only a little more than the Per Vices device, which I'll point out, has no market history, and they have what I
    would have to describe as "kindergarten" Gnu Radio support.

Compare that to the latest gee-whiz ICOM/YAESU/KENWOOD does-everything-with DSP HF-only "rig", and it's dirt cheap. I get frustrated by ham-radio guys
    (and I'm one) balking at "computer stuff is too expensive", and then a month later at the club meeting showing off their latest only-does-one-thing $3000.00
    "appliance".

In the market where the Ettus Radios compete, they're considered *cheap, cheap, cheap*. That market is the academic and industrial wireless development
    market. Perhaps a bit pricey for the budget-constrained hobbyist, but cheaper than those "appliances" so many hams are very fond of trotting out in a
    penis-size competition with their similarly-inclined brethen. And much much cheaper than the "incumbents" in this industry -- Rhode & Schwarz, PenTek,
    etc, etc.

Re:USRP is expensive (0)

Anonymous Coward | more than 2 years ago | (#40570901)

Yeah, because, companies making profits from hardware are evil beyond description.
Why, perhaps we should all move into tin shacks and have all the non-profit consortia provide hardware at cost to everyone. That would be just the Utopia I
    imagine folks like you are looking for, correct?

Or people should make all hardware and software at no profit to themselves, and hunt wild animals to feed their families, and fell trees to make their homes, and
    contrive buckets from bearskins to haul water. But hey, at least all their software and high-tech stuff will have been purchased at cost. With what, I'm not sure.
    perhaps traded for bearskins.

Re:USRP is expensive (0)

Anonymous Coward | more than 2 years ago | (#40572279)

Instead of giving him shit maybe you should recognize that there is a market not being served by Ettus' profit maximization and that the TV Tuner dongle frenzy is an example of smaller margins making equal sums of money for the inventor, but to the benefit of a larger number of people.

Instead of being sarcastic you should encourage him to take out a bunch of student loans, go back to school to study EE, and then upon graduation start a kickstarter project where he sells a USRP tier device for $200.

Re:USRP is expensive (0)

Anonymous Coward | more than 2 years ago | (#40572575)

You realize that the RTL dongle wasn't even *designed* as an SDR device, right? It was designed to service mass-market, consumer DVB-T and DAB reception.
    The economies of scale in the consumer electronics market just don't compare at ALL to what still amounts to a niche market--SDR "platforms" for
    commercial research and development, and academic research, and the occasional hobbyist.

The RTL-SDR "phenom" is entirely accidental. Like discovering that the your $10,000 Ford car actually has an engineering mode that purely by happenstance
    allows you to travel at the speed of light--and accidental billion-dollar feature.

There's a *huge* difference between a SDR platform that *was engineered* to be a general-purpose SDR platform, and one that sorta-kinda works as a "toy"
    some of the time. A bit like complaining that you should have to pay $10,000 for your Ford vehicle, when you bought a used bicycle just the other day
    that gets you from A to B for only $20.00. Surely Ford could learn a thing or two from the bicycle manufacturers?

Re:USRP is expensive (1)

thygate (1590197) | more than 2 years ago | (#40572013)

The RTLSDR is nice, but has VERY poor dynamic range. (8 bit I/Q samples), and no Tx capability. I am however having lots of fun with one, since i can't fork the $1400 for an USRP.

Very little to do with broadcast (5, Interesting)

icebike (68054) | more than 2 years ago | (#40569225)

The game changer here would be in the Cell Phone industry which can substitute a single radio chip to do all the protocols, wifi, cellular, bluetooth, as well as mix and match them at will. New air protocols could be invented over night without waiting for expensive chip developments. Its a cost reduction path as well as a device longevity path.

Although it sounds wonderful when your cell phone is stuck on CDMA or your Bluetooth lacks all the latest capabilities, there are still problems of having an infinite number of antennas available (yes, we already have software defined antennas) in a small place.

There will still have to be frequency restrictions imposed in the hardware itself because the FCC can't afford to allow Joe Random Programmer bringing down jumbo jets. But within authorized bands the ability to use new methods without waiting for the next chip means that we can build a replacement for entire infrastructures much more quickly, while maintaining existing technology for as long as we need it.

Somewhere in this world there are still 029 card punches in use. I suspect we will keep some of our current stuff long after it should be scrapped.

Re:Very little to do with broadcast (4, Interesting)

ceoyoyo (59147) | more than 2 years ago | (#40569347)

I don't think it's going to do much for cell phones. Software defined radio basically shifts the processing from hardware to software. That requires power. For a cell phone, which must operate on a set protocol, there are only drawbacks. Yes, you could upgrade the protocol, but cell protocols don't change very fast and it's unlikely you'd want to run a general purpose cell tower on SDR because of the processing requirements.

What SDR is going to do is revolutionize the unlicensed bands.

Re:Very little to do with broadcast (2)

Baloroth (2370816) | more than 2 years ago | (#40569659)

In theory, though, an SDR cell phone could transition from 3G to 4G-LTE to true 4G with nothing but a software update. That is an extremely cool idea. Tt'd also allow fancy things like using it as a true walkie-talkie or CB radio, and 100% world-wide compatibility. I agree it is unlikely to happen anytime soon, but TFA compares the current SDR systems to the Apple I: it's going to take a very long time before the technology sees it's full usage.

Re:Very little to do with broadcast (1)

icebike (68054) | more than 2 years ago | (#40569959)

Actually I think it will happen VERY soon. Within a year or two.

Why? Because there are so many different radio standards in Cellular use already, in so many different Frequency Blocks, and so many different protocols.
Handset manufacturers would love to have one radio package to install and be done.
Who ever comes out with one of these that can be switched to handle any cellular network worldwide with just an API call wins. Its game over for all the discrete chip makers.

Plus if you can strip out the WIFI, and Bluetooth chipset there will be more power savings. And the software to do this won't be any more trouble or require any more power than the discrete chips do now. (Radio chipsets are already run by software. We call them binary blobs in linux, or Roms in Android.).

Re:Very little to do with broadcast (0)

Anonymous Coward | more than 2 years ago | (#40572931)

Cell phones do already use SDR, the only distinction seems to be that in a cellphone the RF frontends are tuned to 1-5 fixed bands as it allows better performance at lower cost and power. They radio simply switches filter or filter-configuration to switch between 850, 900, 1800, 1900 and 2100 Mhz, but then it feeds into the same 50MHz IF stage and ADC, where software picks out a channel and demodulates it.

Re:Very little to do with broadcast (0)

ceoyoyo (59147) | more than 2 years ago | (#40570021)

In reality, though, a phone that was able to do that would have to have a processor big enough to handle the extra overhead from decoding 4G, would burn through it's batteries in no time, and would be more expensive. And you wouldn't be able to do CB because you wouldn't have an appropriate antenna, although you probably could turn it into an FRS walkie talkie. There are already multi-frequency CDMA/GSM world phones chips. To support CDMA and GSM you need to have the identity module hardware for both anyway.

It might happen someday, but I think things like cell phones are the LAST place SDR is going to be used. Cell phones are already one of the only places you'll find dedicated media decoding chips, and for the same reason.

Re:Very little to do with broadcast (1)

MobileTatsu-NJG (946591) | more than 2 years ago | (#40570023)

In theory, though, an SDR cell phone could transition from 3G to 4G-LTE to true 4G with nothing but a software update.

Please forgive my ignorance on this topic, but wouldn't processing power on-board the device still be a limiting factor? Is it possible that to leap from 3g to 4g that you'd have to get something with a much faster processor? Or is this the sort of thing where the processors are already fast and cheap enough?

Re:Very little to do with broadcast (2)

AmiMoJo (196126) | more than 2 years ago | (#40570159)

Phones already use SDR. It is built into the radio ICs which contain both the analogue radio hardware and a programmable DSP. Android phone updates often include firmware updates for these DSPs, and many phones can be swapped between W-CDMA/GSM and whatever it is the US uses just by changing the radio software.

Re:Very little to do with broadcast (1)

Bob The Cowboy (308954) | more than 2 years ago | (#40570837)

Software defined radio basically shifts the processing from hardware to software.

So what you're saying is that we need hardware accelerated software defined radios?

Re:Very little to do with broadcast (0)

ewanm89 (1052822) | more than 2 years ago | (#40569375)

No, they won't, they lock the chips to specific protocols for a reason, wifi and bluetooth chips are already on the same band and could be combined with very little work, but all the work the vendors do to lock the chips to one specific protocol it's insane. Unfortunately the FCC/Ofcom/ITU regs pretty much say they have to, this is why all wifi cards have some binary blob somewhere (firmware upload to device, firmware already on device...) to stop you accessing all the frequencies the hardware is capable of or with non-certified protocols and yet allow the same hardware to be used in multiple countries with differing regulations.

Re:Very little to do with broadcast (2)

ceoyoyo (59147) | more than 2 years ago | (#40569837)

Most phones already use chips that have wifi, bluetooth and GPS in one.

Re:Very little to do with broadcast (1)

sir-gold (949031) | more than 2 years ago | (#40569515)

I'm sure there are boatloads of wifi/BT/2g/3g/4g patents standing in the way of this.

The recent ITU lawsuits have shown that it's nearly impossible to build even a single-purpose wifi chip without stepping on SOMEONE'S patents, let alone a multi-protocol chip

Re:Very little to do with broadcast (2)

jiriw (444695) | more than 2 years ago | (#40571071)

However ... if you could just use a generic hardware broadcasting device and do all the patent-laden de/encoding in software... You'd have a blast in those large regions of the world where software patents don't hold much sway (Europe, for example... 'though lobbyists try to change that quite vigorously).
And when the U.S. finally learns 'idea' patents only hamper innovation, there won't be a problem at all. It'll be 'just' software ;)

What about signal amplification? (0)

Anonymous Coward | more than 2 years ago | (#40569295)

What about signal amplification? RF PAs are usually only suited for a limited range of the RF spectrum. How does software defined radio get around this?

so? old hat. (4, Informative)

swschrad (312009) | more than 2 years ago | (#40569301)

hams have had SDR for a decade more or less. and software-controlled radio back a little longer. and I seem to remember a win95 radio card that slid into an AT slot back in the mid or late 90s...

Re:so? old hat. (0)

Anonymous Coward | more than 2 years ago | (#40569359)

Yeah - FlexRadio comes to mind whenever SDRs are mentioned.

Re:so? old hat. (0)

Anonymous Coward | more than 2 years ago | (#40569507)

I think the cool thing about this SDR is that this is a transceiver. They don't give many details, but if they've gotten a true software defined transmitter, I'd say that this is a pretty big achievement.

Speaking of which, does anyone have any details about the power output of this thing? The website doesn't give many details.

Re:so? old hat. (2)

AmiMoJo (196126) | more than 2 years ago | (#40570707)

SDR isn't software controlled, it uses software to define the radio protocol in use. Could be as simple as AM or FM modulation, FSK, Manchester or some really complex frequency hopping madness. The point is that a single highly flexible receiver is connected to a DSP that can then replace any number of specialist radios.

Mobile phones already use it. A DSP can process various network protocols like GSM, CDMA and LTE which in the past would have had dedicated decoding/encoding circuitry for each.

Re:so? old hat. (2)

JumboMessiah (316083) | more than 2 years ago | (#40572015)

Yes, there are many HAMs around working on custom SDRs. HPSDR [openhpsdr.org] is one I have some exposure to. It handles RX/TX and comes with open schematics. There are some HAMs doing some really cool [openhpsdr.org] stuff with it.

Software Defined Radios going to ISS in 15 days (2)

ajalics (9152) | more than 2 years ago | (#40569317)

Interesting time to talk about Software Defined Radios.

NASA's SCaN Testbed with 3 Software Defined Radios is launching onboard the Japanese HTV-3 Unmanned cargo vehicle in 15 days. (July 21st)

It's an experimental payload that will be bolted to the exterior of the International Space Station and perform communications experiments with the 3 SDR's contained in the payload.

http://spaceflightsystems.grc.nasa.gov/SOPO/SCO/SCaNTestbed/Payload/ [nasa.gov]

Re:Software Defined Radios going to ISS in 15 days (0)

Anonymous Coward | more than 2 years ago | (#40571539)

July 21st in Japan..
July 20th in the US

And what's more cool is that Joe Schmo can propose to try something, and if it gets through the review process, you too could have software flying on a radio on ISS, at no cost to the experimenter (beyond their own time). Not that lots of individuals are expected, but certainly, university projects and such.

Only half of the widget... (5, Insightful)

Worchaa (774320) | more than 2 years ago | (#40569323)

FTFA: "It could record FM radio and digital television signals, read RFID chips, track ship locations, or do radio astronomy. In principle it could perform all of these functions simultaneously."

Nice try, but no. At least not in a practical sense and certainly not as a mobile rig.

Software Defined Radios are sweet but still dependent on a Physically Defined Antenna. I can see loads of wonderful uses for a broadband, frequency-agile SDR. Actually, I use them often as a Ham radio operator and they are extremely cool. However, there's still the problem of the pesky antenna. You can fudge quite a bit on a receiving antenna, not so much with a transmitting antenna (or a single transceiver antenna), and the engineers out there are very talented and clever at coming up with better designs... but it always tends to come down to the antenna.

My point is that advances in SDR tech is fantastic, but they're not-- nor do I ever see them becoming-- a magic box. What I think they WILL do is streamline production. One super SDR can be dropped into a number of application-specific boxes.

Re:Only half of the widget... (1)

osu-neko (2604) | more than 2 years ago | (#40569853)

You can fudge quite a bit on a receiving antenna, not so much with a transmitting antenna...

None of the uses in the quote you objected to require a transmitting antenna.

JTRS (1)

zjbs14 (549864) | more than 2 years ago | (#40569325)

The DoD should have kicked in a few bucks to this project instead of wasting billions on, and then cancelling, JTRS [wikipedia.org] (Joint Tactical Radio System).

Re:JTRS (1)

Archangel Michael (180766) | more than 2 years ago | (#40569401)

I don't think you understand the purpose of programs like the JTRS. The weren't supposed to actually make anything that was functional. The program was designed to make the contractor a shit load of money off the US Government.

Re:JTRS (0)

Anonymous Coward | more than 2 years ago | (#40569555)

I don't think neither of you understand the cost behind porting legacy/propriatary/new waveforms onto CORBA/SCA compliant SDR platforms.

Creating a SDR platform is easy, if you want the performance of and inter-operability with legacy waveforms and equipment that have ASICs and may rely on platform specific quirks outside waveform standards... well then, you better pony up the cash.

Re:JTRS (1)

Man On Pink Corner (1089867) | more than 2 years ago | (#40570063)

The whole idea behind SDR is that anything that formerly required an ASIC can now be done on general-purpose CPU, and/or an FPGA.

You can pretty much rest assured that there is nothing in any legacy system used by DoD that couldn't be implemented on this device, or on a USRP2.

Re:JTRS (0)

Anonymous Coward | more than 2 years ago | (#40572615)

That's the idea... doesn't mean it'll actually work out in practice.

DoD want's a SCA compliant, Type 1 cryptographic architecture for it's most secure systems. There goes USRP2 out the window right away. But let's ignore that for now.

JPEO JTRS program has ~4million lines of code.

On top of that, these radios are connected into legacy systems that often have stringent timing requirements tied to the legacy radios in order to operate properly.

This comes close: http://rf.harris.com/capabilities/tactical-radios-networking/an-prc-117g/

But it only fills out a minor percentage of what JTRS is supposed to accomplish. On top of that, my bet is that their SINCGARS waveform isn't 100% compatible with this: http://www.exelisinc.com/solutions/SINCGARS-RT-1523/Pages/default.aspx

It may seem to, but remember there's are lots of proprietary and classified specs that you'll never see.

Soooo... my bet is no, USRP2 wouldn't come close to filling everything the DoD wanted.

Re:JTRS (1)

Man On Pink Corner (1089867) | more than 2 years ago | (#40572781)

The four million lines of code wouldn't run on the USRP2 as such; they would run on the host PC or other system. (When you hear figures like that batted about in this context, it's usually because they're referring to a collection of every codec and encryption standard used since the Spanish-American War. The amount of that code that actually needs to run at any given time is much smaller.)

What a COTS SDR would bring to the table is hardware reuse. Things like cryptographic architectures belong at other layers of the OSI hierarchy; they should have nothing to do with the hardware spec.

Maybe I'm wrong. Maybe I'm all wet. Or maybe I'm not the guy who spent $20 billion on radios that either don't exist or don't work.

The FCC heavily regulates SDRs (4, Informative)

TwineLogic (1679802) | more than 2 years ago | (#40569331)

It would be good to change the laws and federal regulations in the United States so that using SDRs would become legal. The current situation is an attempt to enforce "privacy through obscurity" by outlawing radios which could possibly intercept cell phone, pager, or radiotelephone communications (47 USC 302). It is also an attempt to enforce "copyright through obscurity" by requiring that FCC-approved devices respect copyright bits (47 USC 605). All of these problems would be better solved with cryptography. Remember the Clipper chip? That would have been a better path to choose than the current situation.

A few of the relevant obstructions in the form FCC regulations and laws are: 47 USC 2.501, 47 USC 302, 47 USC 605, 47 CFR 2.944, 47 CFR 15.3 (dd).

47 CFR 2.944:
Software defined radios.
(a) Manufacturers must take steps to ensure that only software that has been approved with a software defined radio can be loaded into the radio. The software must not allow the user to operate the transmitter with operating frequencies, output power, modulation types or other radio frequency parameters outside those that were approved. Manufacturers may use means including, but not limited to the use of a private network that allows only authenticated users to download software, electronic signatures in software or coding in hardware that is decoded by software to verify that new software can be legally loaded into a device to meet these requirements and must describe the methods in their application for equipment authorization.
(b) Any radio in which the software is designed or expected to be modified by a party other than the manufacturer and would affect the operating parameters of frequency range, modulation type or maximum output power (either radiated or conducted), or the circumstances under which the transmitter operates in accordance with Commission rules, must comply with the requirements in paragraph (a) of this section and must be certified as a software defined radio.
(c) Applications for certification of software defined radios must include a high level operational description or flow diagram of the software that controls the radio frequency operating parameters.
[70 FR 23039, May 4, 2005]

The penalty for a violation is forfeiture, a fine of up to $10,000, and up to one year in federal prison. See 47 USC sec. 501 This applies to person who purchase the radios as well as persons who sell them. See 47 USC sec. 500 et. seq.
Various internet sources assert that SDRs are "test equipment" and excluded under 47 CFR 15.3 (dd), which reads:

(dd) Test equipment is defined as equipment that is intended primarily for purposes of performing measurements or scientific investigations. Such equipment includes, but is not limited to, field strength meters, spectrum analyzers, and modulation monitors.

I find it difficult to believe the FCC would classify the various SDRs as test equipment, but we will probably find out soon enough.

http://www.law.cornell.edu/cfr/text/47/2.944 [cornell.edu]
http://www.law.cornell.edu/uscode/text/47/501 [cornell.edu]

Before you downvote me because you don't like the laws; consider this: I posted this information because we must change these laws rather than suffer them.

Re:The FCC heavily regulates SDRs (4, Informative)

tlhIngan (30335) | more than 2 years ago | (#40569633)

There is basically no regulation on SDRs.

Receivers - well, you have normal receive rules, though the cellphone one is pretty much invalid these days as no one uses AMPS anymore.

Transmitters - the rule basically says if you have a software transmitter, that software better only allow transmission on the licensed bands.

There aren't any special rules other than "don't transmit where you're not licensed to". The rule for software options is basically ensuring that the user cannot misprogram their transmitter and operate out of band and interfere with other licensed services.

It's the same as an old style transmitter - care should be taken so users cannot readily change the operating frequency and power so they create interference.

And yes, the fines are like that because they apply to unlicensed transmitters as well - if you're transmitting on a band you're not supposed to, you, the user can find your equipment confiscated and fined.

The law is perfectly adequate - manufacturers need to ensure their SDR cannot be used out of the licensed bands (and power envelopes). It's an "SDR" rule because in an old style transmitter, the output stages normally dictate that you can't transmit out of band anyhow without retuning. But since an SDR can be free to transmit on any band without limitation, the software must ensure it's within the license and the user can't trivially modify it to be out of spec.

SDRs are everywhere - the modern cellphone, wifi radio, bluetooth, etc., they're all SDRs internally. These normally have very specific front ends and filters so even if you could set them out of band, they are out of tune and don't transmit squat.

It's a fair rule and prevents frequency anarchy (and frequencies are set aside for various uses).

Re:The FCC heavily regulates SDRs (1)

nurb432 (527695) | more than 2 years ago | (#40570857)

It's a fair rule and prevents frequency anarchy (and frequencies are set aside for various uses).

Not all will agree.

Re:The FCC heavily regulates SDRs (2)

timeOday (582209) | more than 2 years ago | (#40569645)

The laws you quoted appear to restrict transmitting, not receiving. As written it seems to me you could distribute "approved" software that would allow anybody to receive anything.

So, has anybody been prosecuted for receiving signals, or distributing equipment to receive a signal? (Short of circumventing encryption?)

Re:The FCC heavily regulates SDRs (2)

TwineLogic (1679802) | more than 2 years ago | (#40569927)

You haven't read the laws or the regulations I cited in context. In particular, the laws define "interference" from a receiver as being able to listen to AMPS or to decode a digital cell phone or pager signal. I realize that isn't "interference" in any scientific definition, but the law defines it as such, and that's what will count in court.

Recieving is restricted (1)

jrincayc (22260) | more than 2 years ago | (#40572807)

Receiving is restricted as well. Ellis D. Tripp (755736) also posted on this:
http://www.gpo.gov/fdsys/pkg/CFR-2010-title47-vol1/xml/CFR-2010-title47-vol1-sec15-121.xml [gpo.gov]

"scanning receivers and frequency converters designed or marketed for use with scanning receivers, shall ... Be incapable of operating (tuning), or readily being altered by the user to operate, within the frequency bands allocated to the Cellular Radiotelephone Service "

See also http://en.wikipedia.org/wiki/Advanced_Mobile_Phone_System#Frequency_bands [wikipedia.org]

Re:The FCC heavily regulates SDRs (2)

scharkalvin (72228) | more than 2 years ago | (#40569653)

There has never really been ANY law against owning or building ANY radio receiver that could pick up ANY part of the spectrum. Scanners have been sold that blocked out Cell phone frequencies, but people have hacked these to re-enable the reception. Today, the point is moot as Cellphones have gone digital and the scanners were all analog receivers. It was ALWAYS illegal to make public any conversations you heard on ANY "public service" radio band, this includes CB, mobile phone, cell phone, etc. (The amateur radio bands are an exception to this). Transmitters, OTHO ARE regulated by the FCC as to what can be sold. Hams may build their own equipment, and they don't really have to meet any FCC regulations (however the quality of the signals, power levels, bandwidth, etc MUST meet regulations). Commerical amateur radio equipment IS subject to some minimal regulation (such as the imfamous 10 meter restriction to prevent their use on 27mhz CB). The power output levels of a basic SWDR transceiver are about as low as a typical rf signal generator. So yes, these devices WILL be regulated as if they were just lab equipment. It's not until you connect them to an antenna that they actually become a transmitter (and you could hook up a typical tv/radio repair shop type rf signal generator to an antenna an go on the air. I know of some bootleg broadcasters that HAVE done this with a QRP station). If you connect such a rig to a suitable rf linear power amplifier you could have a nice ham rig capable of any mode on any band.
It would be futile to regulate SDR equipment, since they are only one means of getting an illegal station on the air. Want to build a bootleg transmitter? Just look for ANY copy of the ARRL radio amateur's handbook for ALL the data you'd need. It's really not rocket science and the cat's been out of the bag almost a century!

Re:The FCC heavily regulates SDRs (2)

TwineLogic (1679802) | more than 2 years ago | (#40570059)

Again, you have not read the laws I cited a few of. Receivers which can tune to AMPS are illegal. Receivers must not cause interference, and the definition of interference includes the ability to receiver cell phone signals. See 47 CFR 302A (d):

(d) Cellular telecommunications receivers (1) Within 180 days after October 28, 1992, the Commission shall prescribe and make effective regulations denying equipment authorization (under part 15 of title 47, Code of Federal Regulations, or any other part of that title) for any scanning receiver that is capable of— (A) receiving transmissions in the frequencies allocated to the domestic cellular radio telecommunications service, (B) readily being altered by the user to receive transmissions in such frequencies, or (C) being equipped with decoders that convert digital cellular transmissions to analog voice audio. (2) Beginning 1 year after the effective date of the regulations adopted pursuant to paragraph (1), no receiver having the capabilities described in subparagraph (A), (B), or (C) of paragraph (1), as such capabilities are defined in such regulations, shall be manufactured in the United States or imported for use in the United States.

A key definition is "scanning receiver":

(v) Scanning receiver. For the purpose of this part, this is a receiver that automatically switches among two or more frequencies in the range of 30 to 960 MHz and that is capable of stopping at and receiving a radio signal detected on a frequency. Receivers designed solely for the reception of the broadcast signals under part 73 of this chapter, for the reception of NOAA broadcast weather band signals, or for operation as part of a licensed service are not included in this definition.

I submit to you the legal theory that an SDR receiver is a scanning receiver. I could be wrong, but it would depend on the mood of a judge.

Re:The FCC heavily regulates SDRs (1)

jrincayc (22260) | more than 2 years ago | (#40572849)

Um, I agree that the regulation prohibits selling a receiver that can receive AMPS cellular service, but the laws you cite as I read them don't prohibit building or owning a receiver that can receive AMPS.

test equipment exception (1)

jrincayc (22260) | more than 2 years ago | (#40572937)

In order for the test equipment to apply they must be "marketed exclusively as test equipment" title 47 vol 1 15.121(c). However from the website http://pervices.com/about.html [pervices.com] it states "Phi can capture over the air waves, so with the right app, you can watch cable for free." Therefore, Per Vices is marketing the Phi to areas besides test equipment users, so it is illegal.

The Apple II ... (0)

Anonymous Coward | more than 2 years ago | (#40569357)

The Apple II was sold with a separate RF modulator because of potential RF interference. Software defined radio is RF interference, almost by definition. (Seriously. You have to know what you're doing in order to avoid interference, and that knowledge ain't trivial.)

Antenna Length (-1)

Anonymous Coward | more than 2 years ago | (#40569379)

I didn't read the fucking article or even the summary. I understand software-defined radio. I'm not an electrical engineer. I have a feeling the article talks about a software-defined radio as a limitless blackbox of radioing.

I thought there are various factors that still require engineering of physical components to be sensitive to a specific frequency. The first that comes to mind is antenna length.

So what is the article going on about?

Apple I? (2)

narcc (412956) | more than 2 years ago | (#40569429)

Er, the Apple I didn't really revolutionize anything. (The Apple II was easily the more influential Apple computer, but even then that was mostly due to VisiCalc.)

Why not "the MITS Altair of broadcast", ars? You know, a computer that had a real influence on the personal computing revolution.

If they just wanted something really early, why not "the Kenbak-1 of broadcast" or "the H8 of broadcast"?

Before everyone accuses me of worshiping at the alter of a dead cult-leader like Roberts, here's what I'm thinking: They picked the Apple I to attract clicks from readers who would otherwise have no interest in software defined radio.

Re:Apple I? (0)

Anonymous Coward | more than 2 years ago | (#40570111)

MITS?! Other than serving as Microsoft's launch vehicle, the Altair represented an evolutionary dead end. Nothing programmed with toggle switches was ever going to influence the PC revolution, besides bringing a few of the earliest microprocessor hackers on board.

Re:Apple I? (1)

msauve (701917) | more than 2 years ago | (#40571395)

Actually, the Apple I was quite competitive. For $245, you could have a KIM-1, with a calculator keypad and 6 7-segment LEDs, and a slow cassette interface for I/O (you could also connect a TTY and there were programmable TTL ports), and a pretty basic monitor (CLI monitor, not video monitor). It had a bit over 1K of memory, all other expansion was off board. And you had to provide regulated power supplies.

The Apple I, for $667, got you 40x24 NTSC output, easy connection to an ASCII keyboard, on-board voltage regulators, and 4K of memory (expandable to 8K on board).

The Altair was much more expensive, well over $1000 for a usable system (cpu, memory and any i/o other than the front panel), as were the later S-100 systems (the IMSAI, Poly-88, SOL, etc.). It was also huge compared to the KIM-1 or Apple I.

But it was 1977, and the trio of Apple ][, Commodore PET 2001, and Radio Shack TRS-80 when things really took off. Those three made it possible for people with no soldering skills to get involved.

Re:Apple I? (1)

narcc (412956) | more than 2 years ago | (#40572583)

?

I was talking about the computer's influence on the personal computing revolution, not how competitive it was in the market.

Re:Apple I? (1)

msauve (701917) | more than 2 years ago | (#40572913)

...and yet you pointed to the Altair, which really had little influence. Yes, it was first, but left no lasting legacy (S-100 was pretty much dead by the time the IBM PC came out). It's not as if microcomputers wouldn't exist if the Altair hadn't appeared. And where is Altair (or IMSAI, or Polymorphic Systems, or North Star, or Morrow, or Cromemco, etc. now? Clearly, the plain fact that Apple is the largest tech company in the world makes its first product one of lasting importance.

The Apple I was much closer to a modern all-in-one system, you didn't need to add much to be functional. Keyboard and display, about the same as today, and a transformer for power. As I already said, it was the Apple ][, PET, and TRS-80 which made microcomputers pretty much plug and play.

And the real advantage of the A2 was the availability of lower cost, higher capacity, easier to use disk drives, along with the ability to support significant on-board RAM expansion. That in turn made Visicalc practical. Even though it was first on the Apple ][, Visicalc simply didn't work as well on a PET or TRS-80.

A cheaper solution (0)

Anonymous Coward | more than 2 years ago | (#40569445)

Use this device for $25, covers 65-1700Mhz, 8 bit and 2.8Msps:

http://www.ebay.co.uk/itm/DVB-T-USB-Stick-RTL2832U-Elonics-E4000-Receiver-RTL2832-RTL-SDR-Digital-TV-/150809364547

Then use either GNURadio, or HDSDR to view the data and listen to radio, TV, etc.

Beats the hell out of an $850 product that is limited to one desktop machine.

Not a full solution (1)

nurb432 (527695) | more than 2 years ago | (#40570881)

It doesn't transmit.

Obnoxious Apple Namedropping (1, Informative)

Samantha Wright (1324923) | more than 2 years ago | (#40569463)

The TRS-80, the SOL-20, and the PET 2001 [thocp.net] were also officially introduced in 1976. (In fact, the SOL-20 dates to '75... as does the freaking Altair 8800.) I'm pretty sure the TRS-80 was more popular than the Apple I and hence had more direct impact. Ars, you sadden me this day for ignoring these other systems.

Re:Obnoxious Apple Namedropping (1)

Man On Pink Corner (1089867) | more than 2 years ago | (#40570141)

And the time machine was officially introduced in 2012, apparently, if your post is to believed.

Re:Obnoxious Apple Namedropping (1)

Samantha Wright (1324923) | more than 2 years ago | (#40570581)

Ugh. That's a bad header. Okay, so the TRS-80 and PET were a year later; I blame the weird formatting on that page. Still—the Altair was already out. That deserves way more respect than the Apple I.

Re:Obnoxious Apple Namedropping (1)

Man On Pink Corner (1089867) | more than 2 years ago | (#40571275)

I don't agree. The Altair was more Hermes than Prometheus. It brought the message down the mountain, but it didn't bring the fire.

As delivered, the Altair was programmed with switches, not an ASCII keyboard. It had no video output capability. No sound, no graphics, not even a rudimentary text display unless you duct-taped it to a Teletype machine. Some of these shortcomings were later remedied with optional peripherals, but still, it was nothing like an Apple I, much less an Apple ][.

The early Apple and TRS-80 machines were much more influential, and much more recognizable today.

Re:Obnoxious Apple Namedropping (1)

Samantha Wright (1324923) | more than 2 years ago | (#40571925)

Prometheus the Apple 1 is not. There were only 200, after all; the TRS-80 Model I sold ten thousand units in its first month and a half of sales. The Apple ][, sure, but if you consider not shipping with a keyboard to be a critical threshold in a microcomputer's ability to support the masses, then surely the absence of a significant user base is more important than coming out first.

There are much cheaper SDRs (0)

Anonymous Coward | more than 2 years ago | (#40569487)

Try rtlsdr.com in a few days after they recover or websdr.org.

I'm building a Softrock Ensemble II $70 from kb9yig.com

The UPSDR and Phi are far more capable, but at a price.

GQRX (2)

SealBeater (143912) | more than 2 years ago | (#40569897)

Hopefully this guy won't be mad at the shoutout.

There is a lot of work being done to make GnuRadio in general more accessable

GQRX http://www.oz9aec.net/index.php/gnu-radio/gqrx-sdr [oz9aec.net]

Re:GQRX (1)

Man On Pink Corner (1089867) | more than 2 years ago | (#40571569)

There is a lot of work being done to make GnuRadio in general more accessable

If they wanted to do that, they could start by shipping Windows binaries that would work with the Funcube and other dongles.

Re:GQRX (0)

Anonymous Coward | more than 2 years ago | (#40572173)

There is a lot of work being done to make GnuRadio in general more accessable

If they wanted to do that, they could start by shipping Windows binaries that would work with the Funcube and other dongles.

GP said "more accessible", not "accessible to retards with toy computers". Give it another couple of years...

Re:GQRX (0)

Anonymous Coward | more than 2 years ago | (#40572521)

This is why you lose. That, and the whole not-bathing thing.

Re:GQRX (1)

thygate (1590197) | more than 2 years ago | (#40572049)

there's also HDSDR (http://www.hdsdr.de/screenshots.html), and sdrsharp (http://sdrsharp.com/index.php/downloads) for windows.

Re:GQRX (1)

thygate (1590197) | more than 2 years ago | (#40572105)

GnuRadio is not a front-end, it's a framework (mainly python and c) for processing signals (DSP) with lots of functions for filtering/demodulating/.. There is gnuradio-companion which allows you to design in a GUI where you place blocks and connect them.

Freq-Hopping Encrypted Tac-COMM (2)

BlueStrat (756137) | more than 2 years ago | (#40571435)

One thing to note that I haven't seen mentioned yet is that this goes a long way towards making secure & encrypted tactical radio communications much, much more do-able and affordable for private citizens. A capability that's up till now largely been restricted to LEAs and the military.

This unit's flexibility make setting up frequency/band-hopping and encryption relatively easy. This capability in civilian hands is sure to be disliked by US TLAs and police.

It makes me wonder whether the government will attempt to outlaw certain programs and/or regulate what software is "legal" to have loaded in such a device, and/or require device capabilities be hardware-crippled/restricted to be legally sold.

After all, according to the government, it's right and proper that the government conceal it's communications and activities from the citizens, but citizens may certainly not be allowed to communicate securely without the government being able to monitor if they wish.

"The liberties of a people never were, nor ever will be, secure, when the transactions of their rulers may be concealed from them." - Patrick Henry

Strat

$15 DVB-T tuner (RTLSDR) (2)

thygate (1590197) | more than 2 years ago | (#40571927)

I'm surprised no-one has mentioned the RTLSDR yet. A $15 DVB-T Tuner than can tune from ~70MHz to 1700MHz. Maximum bandwidth is about 2MHz. It has poor dynamic range (8 bit ADC), but for receiving strong signals it's awesome. There is a source block for gnuradio, and some nice tuners for windows (HDSDR, sdrsharp, ..). Lots of cool stuff to do. For instance I've successfully received MODE-S transponder replies from airplanes as far away as 200km with the stock antenna. Tuning to FM radio, portable mobile radios, DECT, GSM, Exploring the spectrum, .. Of course it cannot compare to an USRP or this new Phi, but it's very cheap and is perfect for getting started, and does not require a HAM license. check here : http://sdr.osmocom.org/trac/wiki/rtl-sdr [osmocom.org]
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