I would like to share an issue I am experiencing with three Proxmark3 devices where the LF antenna is reported as unusable.
I own three Proxmark3 devices that were working normally until yesterday. Both the LF and HF antennas were functioning properly. For some reason (I suspect the USB hub), while trying to read a T5577 card, I was unable to identify the chip type using the lf search command.
When I ran the hw tune command, I received the following information:
[usb] pm3 → hw tune
[=] ---------- Reminder ------------------------
[=] hw tune doesn’t actively tune your antennas,
[=] it’s only informative.
[=] Measuring antenna characteristics, please wait…
[/] 10
[=] ---------- LF Antenna ----------
[!] LF antenna is UNUSABLE
[=] ---------- HF Antenna ----------
[+] HF antenna: 13.85 V - 13.56 MHz
[+] Approx. Q factor (*): 4.0 by peak voltage measurement
[+] HF antenna is OK
(*) Q factor must be measured without tag on the antenna
[-] Not showing LF tuning graph since all values is zero.
I had the same problem with another Proxmark3 reader.
In the end, I took a third reader, connected it, and when I ran the hw tune command, it showed that the LF antenna was MARGINAL.
I tried to read the card again, but without success. When I ran the hw tune command once more, it showed that the LF antenna was UNUSABLE.
Do you know what could be the cause of this issue, and whether it can be resolved, and if so, how?
Are you sure that you’re firmware and bootloader and client software are all the same version? What does the screen show immediately after running the pm3 command? It should spit out a bunch of stuff.. post screenshots for each of your proxmark devices, clearly labeled which is which. I want to see three separate screenshots, clearly labeled proxmark 1, proxmark 2, and proxmark 3. Screenshots need to include the version information for firmware, bootloader, and client.
I tried tightening the screws, and I also tried removing the middle spacer in case the signal might be stronger. I also attempted to re-solder the contacts on the small board where the LF antenna is connected, but none of this resolved the problem.
Put the middle board back and make sure all your screws are in place and tight, and make sure your LF antenna board is correctly oriented. The middle board helps improve tuning and performance (it’s meant to separate the antenna from the electrical components on the board which cause interference).
I managed to assemble two working units out of three Proxmark devices, and now the LF antenna is working on both of them. I removed the board from the third Proxmark about two years ago and it worked until now, but that’s fine — the important thing is that I have at least two units that are working.
What do you think about the firmware versions we are using? Are these the latest ones, or could you perhaps share some newer firmware versions than the ones I am currently using?
There’s definitely newer firmware, but how you get there depends on what you’re running on. Are you on Windows or Mac? If Windows, are your running proxspace or some other linux type environment? If you’re on Mac how did you get your current firmware and client set up? Are they pre-compiled binaries from Brew or something like that or did you download the source and compile?
