ProxMark3 low voltage on lf and hf antenna ( < 23 mV ) No implant read

[amal]

It can be tricky positioning the proxmark3 over a NExT, especially when it’s implanted and hard to pin down exactly where it is under the skin.

First off, if you’ve not found this gem, I would make use of the delay command;

How to add a delay to Proxmark3 commands for implantees

Having an implant in your body and trying to use the Proxmark3 can be a tricky balancing act of trying to hold the Proxmark3 antenna just so over your implant and then trying to hit Enter to initiate the command. But, there is a way to solve this by using the msleep command along with command chaining to add a delay between pressing enter and the command you want to execute against your implant is actually run. For example, to perform an lf search with a 3 second delay before actually performing…

Now you have a fighting chance to properly position the LF antenna coil directly over the NExT.

When it comes to HF, it’s important to note that the actual HF antenna coil is on the bottom PCB, not the middle PCB which is what you see looking down at the top. If you look closely at the bottom PCB you can see the traces of the HF antenna coil running on the top side of the bottom PCB… basically sitting between the bottom PCB and the middle PCB. Because of this, you get much better reads of x-series implants if you actually just place the proxmark3 down on your NExT so the bottom PCB is resting with the antenna traces running perpendicular across your NExT.

Finally, the voltage levels do vary a considerable amount with every proxmark3. If your hw tune indicates both antennas are ok, then they should work just fine with the NExT when ideally positioned.