[Discuss-gnuradio] Re: RFID Capture

[Michael Buettner]

Are you using the ThingMagic in monostatic mode (one antenna that does RX and TX)? If so, you probably won't be able to see the tag reply.  Further down the receive path the ThingMagic has circuitry that removes the strong TX signal leaving only the tag reply, but I assume you are tapped in before that. You MIGHT have better luck if you use the reader in bistatic mode and tap in at the receive antenna, particularly if you don't use the full 1W output power. Another option would be to just put the USRP antenna near the tag, and receive both reader and tag commands there. I have had pretty good luck with that, and can decode tag responses from a few feet away.

michael

> Hello All,
>  I am trying to capture the communications between a RFID reader and
> an EPC Gen 2 tag (920 MHz).  I tapped directly into the antenna of a
> Thinkmagic M5e RFID reader.  I turn it on and it starts reading the
> tags.  When I look at the raw signal from the usrp or an Agilent
> signal analyzer, I can clearly make out the reader-to-tag data bursts.
>  But, I don't see the tag-to-reader bursts.  I know they should be
> considerably smaller in amplitude, but all I see is noise.

> Has anyone had any luck capturing this type of data?  Any suggestions
> would be greatly appreciated.

> Thanks in advance,
> Kevin



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