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frequencies for keyfob or rfid cards?


defaultzero
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Is it possible to find rfid card frequencies for employee badges? Or keyfobs? And if so how to decode?

Im curious if sdr can sniff nfc devices like hotel cards and nfc tap cards for subway and bus passes. Just curious. This sdr thing has me curious about tons of stuff. Maybe hackrf can be used to find binary info and transit the data unto a fob or card to clone

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The R820T on those cheap dongles does 24-1850 MHz. Not all radios are created alike, especially the cheaper ones, so YMMV but the end result will be within those ranges.. With WIFI operating at 2.4 GHz, it's out of range for the R820T.

Be careful with the naming. SDR simply means Software Defined Radio which is a generic term. The HackRF, for instance, is an SDR which CAN receive signals within (and beyond) the WIFI operating spectrum (and, thus, can receive interference from a microwave). The cheap dongles you can buy use the Realtek RTL2832U demodulator and the Rafael Micro R820T tuner. Your question was probably about the tuner.

Edited by Cooper
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Hmmm... I know several folks who have been working on similar things such as checking out keyfob frequencies, however I think they change everytime so it'd be hard to decrypt. Dragorn did this which looks pretty cool: http://blog.kismetwireless.net/2013/08/playing-with-hackrf-keyfobs.html

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Looks cool. I've been meaning to have a look at the key fob for the door to the parking garage under my appartment building. I'm fairly certain it's a fixed sequence, given the deplorable quality of the fob: the main button actually _fell off_ so I had to solder one of the unused buttons in its place, plus the clip to the battery compartiment broke off so that's now a big lump of scotch tape which I need to press to complete the circuit.

Gah! So many projects, so little time...

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defaultzero, fasttrack uses a mifare based system for RFID, it's actually really broken and easy to duplicate but I'd recommend not doing it.

snubs, thank you!!!! I've been using nothing but gnuradio for everything and that site opened up a whole new set of ideas.

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Cars are 433Mhz in the UK which is in the range of those cheap SDR, NFC is 13.56 which is not unless you are using an up-converter, RFID as a generalisation is 125KHz or 13.56MHz, with 125KHz used really heavily in door entry systems. Less commonly you have some used for warehouse product tracking in the late 800MHz's in Europe and early 900MHz's in the US.

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