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Author Topic: Software Defined Radio and HackRF  (Read 717 times)
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I suggest everyone reads this article.  It is very interesting and enlightening.  Heck, it could be a pertty nice challenging project.  None of these parts are expensive at all.  What do you think of this, is this a threat to society?  How much of the data that goes over phones these days is unencrytped?  Wouldn't encrypting everything be the correct way to mitigate this danger?

http://www.forbes.com/sites/andygreenberg/2012/10/19/darpa-funded-radio-hackrf-aims-to-be-a-300-wireless-swiss-army-knife-for-hackers/

Quote
Since the days of Alan Turing, the promise of a digital computer has been that of a universal machine, one that can be a word processor one minute and a robot brain the next. So why are radios, a technology even older than computers, still designed stubbornly to do one thing–like 3G, Wifi, FM, or GPS–for their entire lives?

In fact, the era of the single-purpose radio is over, says Michael Ossmann, the founder of an Evergreen, Colorado company called Great Scott Gadgets. And he believes he’s built the one cheap, hacker-friendly radio to rule them all.

...

“Pretty much any wireless device that you can think of would be in the frequency range covered by HackRF,” says Ossmann.”Just from observing [a signal] over the air, you can reverse engineer it completely to figure out the information transmitted over the network, and potentially inject your own transmissions onto that network. All of that can be done with one HackRF device and a laptop.”

With HackRF in the hands of hackers or security researchers, in other words, no wireless signal would remain secure just by virtue of using a unique, unfamiliar frequency. Ossmann says that tools like HackRF mean wireless communications will need to evolve beyond the “security through obscurity” model of protecting communications that has long been considered outmoded in the wired computing world.

...

Read the rest at the link.  Hopefully I didn't reproduce too much.

http://ossmann.blogspot.com/2012/06/introducing-hackrf.html
« Last Edit: October 23, 2012, 12:45:52 pm by JoeN » Logged

Vexatious Sampler

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I am going to supply my first reply here.  Are there any radio / data conversion experts out there?  Here is what he gives as HackRF project goals:

•transmit and receive
•operating frequency: 100 MHz to 6 GHz
•maximum sample rate: 20 Msps
•resolution: 8 bits
•interface: High Speed USB
•power supply: USB bus power
•portable
•open source hardware and software
•low cost

OK, it all makes sense to me.  But one question, how can a 20Msps 8 bit ADC/DAC be sufficient when working at these frequencies?  That's all it takes?  I wonder if you could do more with some of the (admittedly more expensive) faster high resolution ADCs on the market.  There are 16 bit ADCs now with 100msps data conversion rates or faster and obviously far faster 8 bid ADCs.  How can this be enough?  Thanks.
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I am going to supply my first reply here.  Are there any radio / data conversion experts out there?  Here is what he gives as HackRF project goals:

•transmit and receive
•operating frequency: 100 MHz to 6 GHz
•maximum sample rate: 20 Msps
•resolution: 8 bits
•interface: High Speed USB
•power supply: USB bus power
•portable
•open source hardware and software
•low cost

OK, it all makes sense to me.  But one question, how can a 20Msps 8 bit ADC/DAC be sufficient when working at these frequencies?  That's all it takes?  I wonder if you could do more with some of the (admittedly more expensive) faster high resolution ADCs on the market.  There are 16 bit ADCs now with 100msps data conversion rates or faster and obviously far faster 8 bid ADCs.  How can this be enough?  Thanks.

I think most wide range and very high frequency RF applications working at these frequencies utilize hardware based DDS ICs (Analog Devices is a leader) to generate the low level RF frequencies of interest that are used both in receive applications (via the DDS as local oscillator that is mixed down to a lower frequency for fixed IF frequency that is more easily processed with a ADC that operates at base band or at lower fixed IF frequency for the demodulation or modulation of the signal in upconversion for transmitting applications.

Do to answer your question more simply a ADC that works at these very high RF frequencies is not required, the ADC is just used at lower frequencies to generate or to demodulate the information that will then be mixed with and upconverted to the desired RF frequencies. 

The modern DDS chips available have tremendous capabilities.

Lefty
« Last Edit: October 23, 2012, 02:32:57 pm by retrolefty » Logged

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Ah, it makes sense.  If the IF frequency is reasonable enough then the ADC can be a mid-power one and not one of those non-exportable weapons grade ones.  I don't know a lot about how front ends change RF to IF but since they obviously do it well enough this finally makes sense.

What do you think of this radio?  $100,000 has become $1200 has become $300 and soon probably $17.97 at WalMart.
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Ah, it makes sense.  If the IF frequency is reasonable enough then the ADC can be a mid-power one and not one of those non-exportable weapons grade ones.  I don't know a lot about how front ends change RF to IF but since they obviously do it well enough this finally makes sense.

What do you think of this radio?  $100,000 has become $1200 has become $300 and soon probably $17.97 at WalMart.

The IF is in the 2.3 to 2.7GHz band.  But that then is direct-converted by a MAX2837 transciever chip to/from baseband quadrature where the DAC and ADCs can handle it (2 each for quadrature).

wiki is here: https://github.com/mossmann/hackrf/wiki
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