Jose Vicente Campos

10 posts

Jose Vicente Campos

Jose Vicente Campos

@Jose4Vi

Madrid, Comunidad de Madrid เข้าร่วม Ağustos 2017
10 กำลังติดตาม44 ผู้ติดตาม
Jose Vicente Campos
Jose Vicente Campos@Jose4Vi·
@FelipeC31024269 Hola Felipe, acabo de darme cuenta que tu mensaje es de hace 1 año! lo siento mucho no se porque no lo vi
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Jose Vicente Campos
Jose Vicente Campos@Jose4Vi·
@gentilkiwi Hello Benjamin! I am surprised by the good capture you have obtained with a simple NESDR! Thanks!
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🥝🏳️‍🌈 Benjamin Delpy
Failed (non tuned)🥝antennas are good for cheap NFC spying Always amazing times when playing with @Jose4Vi's NFC laboratory... trust me and give it a try!
🥝🏳️‍🌈 Benjamin Delpy tweet media🥝🏳️‍🌈 Benjamin Delpy tweet media
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Jose Vicente Campos
Jose Vicente Campos@Jose4Vi·
@5ch4um1 @jilles_com Have you tried to decode the bytes of the signal to get valid messages from the reader and card in all possible speeds and modulations? If there is any way to improve the decoding I am interested.
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Re: trasado
Re: trasado@5ch4um1·
@Jose4Vi @jilles_com idk, worked just fine for me with gnuradio. Even at 2.12 msps iirc. You might want to play a bit with the placement of the components, like tag, reader and antenna? If you find a sweet spot, even the responses come in loud and clear. ;)
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Jose Vicente Campos
Jose Vicente Campos@Jose4Vi·
@5ch4um1 @jilles_com the signal simply does not have enough dynamic range to properly detect the symbols, the card responses are very weak compared to the signal level due to the 8 bit resolution, this means that good results are not obtained using RTL-SDR , that's why I recommend using Airspy.
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Re: trasado
Re: trasado@5ch4um1·
@Jose4Vi @jilles_com "Only [...] some responses " still sounds supersticious to me, you either can get the responses, or you can not, because something is wrong with your setup. There is no voodoo involved that makes some responses disappear due to sample rate or bit depth imho?
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Jose Vicente Campos
Jose Vicente Campos@Jose4Vi·
@5ch4um1 @jilles_com There is nothing wrong with a classic RTL-SDR receiver, simply to decode NFC signals it is not the best option due to its bandwidth and the resolution of 8 bits per sample. Especially for the load modulation generated by the card.
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Re: trasado
Re: trasado@5ch4um1·
@Jose4Vi @jilles_com "only some responses in very clean signals", because sample rate and only 8 bits ? Still sounds strange to me...I mean, sure, if you're half a meter away you probably won't get a clean signal, but why blame the receiver when it has nothing to do with it?
Re: trasado tweet media
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Jose Vicente Campos
Jose Vicente Campos@Jose4Vi·
@5ch4um1 @jilles_com The main reason to need 10Msps (or more) is the complexity of decoding the card responses at high speeds like 424kbps, it is necessary to determine the shape of each symbol, the niquist frequency is not enough for it.
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Re: trasado
Re: trasado@5ch4um1·
@jilles_com Wow, that looks like a lot of work. Why the concerns about the rtlsdr though? With 3 mbps, you are almost at 30 times the symbol rate of nfcA, plenty to make Mr. Nyquist happy?
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Jose Vicente Campos
Jose Vicente Campos@Jose4Vi·
@giammaiot2 @hydrabus @CyberAntani Hello, I am the author of nfc-laboratory, I think we are a great community in which we all contribute, once the misunderstanding has been clarified, let's continue working to help each other.
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GiamMa-based researchers SDR R&D IoT
@cemaxecuter The code is not mine, but on github they opened an issue to understand how to install and / or compile. I received an .exe but I don't think I can share it.
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