yan 🐇random n00by question: say that i have a key card and already determined that it's not NFC. what's the easiest way to figure out what protocol it is using? assuming it is passive RFID, is there a DIY way to read it (like with an SDR)?
Tomas SA2TMSPut a coil around it and start sweeping from a couple of kHz up to a few MHz maybe? Say short bursts then listen for echoes. A MIMO SDR like LimeSDR might be good for this