HackRF, an open source SDR platform(kickstarter.com) |
HackRF, an open source SDR platform(kickstarter.com) |
Their hardware is significantly meatier, supporting frequencies from 100kHz to 4GHz with a bandwith of 250MHz. The HackRF only has a bandwith of 20MHz, and bottoms out at 30MHz.
I haven't heard much from them, or discussion about them, but they are out there.
http://www.pervices.com/shop/index.php?route=product/product...
At that price point you might as well start looking at USRPs.
If you are looking for something that you can run from a USB cable, this could be the perfect tool. Someone called this the Bus Pirate of RF and I think its a great way to describe this tool.
The SDRs from Per Vices are geared towards low latency and high bandwidth. You can't squeeze 4x PCIe bandwidth into a USB cable. Neither can you get sub microsecond latencies. You can't get this over an ethernet connection either. This is the application where the Per Vices SDRs come out as clear winners.
We've been considering getting one of these: http://www.metageek.net/products/wi-spy/
It would be great to instead have a bit of kit that could be repurposed like HackRF.
Caveat: I work on Ubertooth for Michael Ossmann
http://sdr.osmocom.org/trac/wiki/rtl-sdr http://www.nooelec.com/store/tv28tv2.html
bladeRf, USRP and now HackRF are def a step up but big difference in cost.
There is also http://www.RFSpace.com, http://www.Winradio.com and http://www.flex-radio.com for commercial offerings.
aka the former kb9yig operation.
I have a liteII combined kit built for 30 meters. Works pretty well! Wide enough BW that with a 192K sound card (or was it 96K?) I would listen to one of the aircraft weather transmitters.
Note this is narrowband low frequency rx and tx gear, whereas there's two separate "cultures" of SDR people and one lives to demod wifi and the other lives to do advanced DSP on 160 meters or whatever. And the two don't often meet.
HackRf is even offering a Ham-it-up upconverter to go with, the same one you would use with a DVB-T dongle. This gets you into the lower range but uses a mechanical switch to engage. Would really like soft control of it and be more integrated into the design. I might even try to wire a relay in to a Ham-it-up along with a raspberry pi for a integrated device that can go below 30Mhz with IP based connection.
Shannon's law is not to be denied! (And what decade did it rename from "Shannons Law" to "Shannon–Hartley theorem" anyway?)
And you don't need to be an jerk and interfere with broadcasts. It's an antisocial activity frowned on by 99.99 percent of the public and hardware hackers. There's plenty of good science that can be done in all aspects of RF experimentation for a small investment of time and little money.
https://github.com/mossmann/hackrf/wiki/Jawbreaker
* half-duplex transceiver
* operating freq: 30 MHz to 6 GHz
* supported sample rates: 8 Msps to 20 Msps (quadrature)
* resolution: 8 bits
* interface: High Speed USB 2.0 (with USB Micro-B connector)
* power supply: USB bus power
http://www.kickstarter.com/projects/1085541682/bladerf-usb-3...
... since I already have one.
HackRF appears to be about half the size, which is very nice. Freq range is 30-6000, vs. the bladerf which is 300-3800.
Bladerf is USB 3.0, however, and appears to have a higher sample rate ? "capable of capturing 40MHz 12-bit full duplex quadrature samples in realtime."
The HackRF appears to be about half the price, currently.
http://www.nvidia.com/docs/IO/116757/NVIDIA_i500_whitepaper_...
Edit: I sent a question on kickstarter asking about TX power limitations so if mossman answers it, the answer will appear in the FAQ section.
What it really depends on is your modulation method.
So say you want to operate legally as a ham radio op on 5760.1 operating CW. Well with a reasonably high gain antenna -15 dBm is OK. COTS MMIC amps and some filters and you'll have a vaguely competitive contest rover. I would imagine QEX/QST and the like will have ham radio band amp designs for a couple bucks soon enough after this thing rolls out. Looking at the cost of a FT-817 and a transverter, I imagine you could save quite a bit of dough using this device... Given $200 I could probably scavenge up some TR relays good for 5 cm and maybe a whole watt or so. Placed in front of a modest rover capable dish this could pretty much kick butt. Plus or minus phase noise, which hasn't been discussed, and frequency stability (I'm guessing no 10 MHz GPSDO input) (edited to add, and I haven't seen a noise figure spec yet either...)
On the other hand if you insist on trying to do NTSC ATV ham radio operation around 427.250 you'll find that a smokin +5 dBm on a 6 MHz wide signal will get you perhaps across the room.
Second, can this do GSM, receive at least? Frequency band works, but maybe it doesn't have the bandwidth?
I looked at their product specification and there isn't any mention of phase noise of the local oscillator. It turns out that a critical requirement for tuning into GSM signals is the phase noise or jitter of the local oscillator. Chances are, they are using a pretty good cystal, but probably not good enough for a GSM base station.
There is a good reason why GSM base stations all run off rubidium standards. In fact, you can grab 10MHz rubidium standards for a very (relatively) cheap price off eBay. They are all from decommissioned cell towers.
There is a possibility that you can still tune into a GSM signal with a substandard local oscillator. However, this behaviour would be intermittent.
Then there's all kinds of rules about transmit power. For instance, last I knew you could transmit unlicensed on the public FM and AM radio bands so long as you're under some minimal threshold - I think it was 1W.
LOL no, you know .gov they make it as complicated as possible. If I recall the AM is DC input power limited and the FM limits are some weird field strength which is non-trivial to measure. Google for 47 CFR 15 and you're looking for part C 15.221 and .239 probably. You can read this stuff for free at gpo.gov.
There are about a zillion other part 15 bands you can legally operate under if you're willing to bother figuring out how.
If you're smart enough to figure out how to legally operate part 15, you're certainly smart enough to get a license to operate part 97, which doesn't have even a fraction of those goofy restrictions and is the original techie social network.
http://www.ntia.doc.gov/page/2011/united-states-frequency-al...
Some uses I would consider besides general scanning and exploration would be: amateur radio (multiple bands), NOAA weather stations and satellites, various aviation services, device monitoring and prototype assistance, etc....
You could read more about this topic at http://www.arrl.org/
I donno if the startup idea is an online course for CS to understand EE or EE to understand CS or both or ... ?
http://www.ti.com/lit/ds/slws011d/slws011d.pdf
Back then they used a 40 bit rolling code.
Found here: http://auto.howstuffworks.com/remote-entry2.htm
QRP guys have crossed continents on less than a watt. I remember from my undergrad days that we've played with band passing the human voice. We managed to get surprisingly good results with 500Hz of bandwidth.
There's a lot of interesting things you can do with more power and more bandwidth. To echo a lot of the other comments made already, if you are doing this without much thought, this is generally frowned upon.
Power is easily solved by an external amplifier.
Increased bandwidth would be nice, but 20MHz is plenty. While you might need that for microwave experiments (wifi, gsm, etc, and spread-spectrum experiments), the big advantage of the bandwidth is being able to listen in to everything at once, and see where signals are at a glance, without tuning through frequencies. Being able to glance at an entire band, and immediately see where QSOs are happening is pretty cool. Or you could record all of the FM broadcast spectrum, and decode it at your leisure later. That's not too practical, but is pretty cool. And 20Mhz is wider than every ham band 2m and lower.
And 500 MHz isn't quite enough for voice - SSB is generally 2.3 - 3 kHz. 300-500 Hz is ideal for CW (morse code), and digital modes can use even less.
Also, if you want to go all the way down to DC, the upconverter approach doesn't really work.
[1] http://en.wikipedia.org/wiki/High_frequency [2] http://www.nooelec.com/store/ham-it-up-v1-0-rf-upconverter-f...
Not my experience at all. I have been wallpapering my radio room with 1st place wins as a QRP entrant in the ARRL 10M contest in December for a couple years.
During a Es opening my 5 watts might only be S9+10dB whereas a guy with a 1500 watt linear would be S9+30dB so you can see why its not much of an issue.
Before I got a modest brick for 6M it was the same deal every July and December. I'd have 5 watts out and work guys 1000 miles away who had signals S9+20dB and I'm sure I was "merely" S9 or so on their side.
Another thing is the ops on 6M are gentlemen, by self selection this is not 80M or 20M sideband. They're glad to work a "weak" signal and don't turn down their RF gain or whatever those HF ops do.
When propagation smiles on you, power out doesn't matter. When it doesn't, well you're screwed even if you have illegal levels of power.
I live in a part of the country where the 1000 mile Es donut covers pretty much all the sand states. So I have a lot of Grids! I near got DXCC during just one VHF contest in the spring in just one day!
Thats what I thought. We had a few teams look at ways to carry human voice with less BW in a sensory communications course. The winning team did it with 500Hz. I remember it clearly. There was a stunned murmur during their project presentation when they announced their results.
I don't remember the exact numbers, but the gist of it was, they applied 2 bandpass filters, one on a lower frequency range and the other on a higher frequency range. Both passbands were 250Hz wide. They combined the two signals together as a 500Hz signal. The pass bands were seperated by 500Hz or 1kHz IIRC. So pretty much they kept the lower and higher frequencies and threw away the rest. The result was pretty good. Human languages have a lot of redundancy in information and the quality was good enough for general conversation. It was comparable to what you have on a cell phone.
You'll also note the prices, and that those are receive-only devices. Some of the reason the price is so high is that we did all the RF design in-house, designing to our specs. A lot of the cheaper boards out there have less amplification, no (or too little) filtering, and use an integrated LO/mixer/digitizer/baseband chip, which limits them to the specs that chip can handle.