It might work. You would have to ensure that there were no surface mount components (like caps or resistors) hidden on the antenna connector or body. Sometimes they’re so small you can barely see them (0201s and 01005s, I’m looking at you).
Inductance is all that matters for resonance, so you could replace it if you found the correct connection points. Another factor is power delivery though, and that’s affected by impedance. Two coils with the same Inductance don’t necessarily have the same resistance (different thickness/length wires) or capacitance (more or less insulated surfaces in close proximity), and that can seriously impact the impedance. More impedance at the target frequency means less power delivered.
You could create a type of patch antenna or antenna extension though.
I was wondering if it would be possible to make a semi-universal patch antenna that could be permanently stuck to a reader that works well with x series transponders assuming the reader provides enough power. But I assume it is not that simple. I barely understand what I am doing with standalone coil design, let alone an coil that acts as an adapter. Gives me a headache just thinking about it rn.
Hmm, yes, and no. CB antennas are designed to be interchangeable. There is a standard / expectation they have to meet. The CB expects that the antenna connected to that jack at the back will meet those requirements (50 ohm impedance, resonating at 27MHz). Making your own antenna that does not meet the expectations and electrical requirements can actually damage the CB.
So while it is possible to make interchangeable antennas for RFID (as seen with the DT LF antenna), you have to fully understand what the circuit is expecting. These expectations and requirements are not standardized at a point in the system like CBs are at their antenna connector. They depend on a plethora of variables.
In regard to the RDV4 and the interchangeable antenna, I am not sure but based on the 3 pins for the antenna I would guess that it is more than just a coil, I expect at least the capacitor for the coil to be on the antenna board as well. Aka the RDV4 system has been designed with modular antenna in mind with it’s own spec where as most RFID systems are designed as one tuned unit.
So an update on this lock, it seems to have stopped working. I cannot get it to read my implant anymore. Works fine with cards.
I’m guessing the warmer weather may have pushed the tuning of the antenna out just enough so it won’t read anymore.
I last reported it didn’t seem to work in hot weather. I now take that back.
Since it’s like a billion degrees here, I installed an A/C in my garage. That means my “routine” of entering/exiting through the garage 99.9999% of the time has changed and I now use the front door with this lock 99% of the time as to not let the cold air out of the garage. I can say this lock does indeed work when it’s well over 100 deg F. It is just super critical of placement and using it regularly has given me the practice to be able to get a good read on the first try 7 out of 10 times.
I need to make a fist so I know exactly where the ends of the implant are as I have found that it is even sensitive to lateral placement across the antenna. The antenna on the xNT is biased towards one end of the tube, and you have to place that end right on the antenna. If you miss the first time, it can be a pain to get it again without putting it back to sleep and trying again. But it does work and I’ve definitely gotten better at getting a good read on the first attempt. And it is glorious when that happens.
Here’s me trying it a bunch of times. It was actually harder as I was trying to make sure I got the video framed right making my placement less accurate.