On the lf antenna?
That seam high, I don’t remember what the “normal” is and how far I’ve pushed it long term.
The risk is to blow the adc
With your LF antenna and board i get 24v i have no idea where my stock antenna is so i cant test against that.
My antenna is tad hurt than the stock in terms of voltage 
The stock is 20-21 from memory but I haven’t looked at it in a while. I need to check my notes.
I think I’ve pushed it to 25 or so during testing, but I never ran it long term above that
This is my stock antenna at 39v. I’ve had the device for a couple of years and it has always been around that voltage. Possible QC issue?
it seems to me you may need to correct your firmware.
I’m in the UK, but I’d happily take a test board and could cover the shipping if the cost isn’t too crazy.
I did update the client & firmware recently so it’s possible I messed something up. All version numbers look like they match though…
Let me see how much it is, it’s a small PCB so it might fit in an envelope
The version seam good, I don’t know.
I’m no proxmark/coding expert …@Iceman might be able to help with that one 
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International stamps are pretty cheap, i wanna say around 1$
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@glob , looks like you’ll get a jacked up prototype PCB in the slooow mail 
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what is the issue? tldr
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Poor performance with a bar antenna despite it being resonant.
The pm3 client warns that I may be running generic firmware on an RDV4, while I’m actually running an ‘easy’ device. Unsure if that’s relevant or just a false positive. Firmware and client versions all match.
Voltage is also apparently too high at 46v (similar when using stock antenna). I’m not sure what I can do about that.
Thank you @XEMON ! I have your board installed for testing now.
The measurements are very similar, and sadly performance is more or less the same. It works, but only about as well as the stock antenna.
It seems as though your PM3 is slightly larger than mine. I had to employ some rather advanced electronics techniques to get a solid connection:
I wonder if I just have a duff PM3. I bought it from PiSwords on Aliexpress a couple of years ago. Apparently they are the good seller, but I guess QC is never perfect.
The PCB size is wired … no idea on he different version.
Kapton tape: like screws but better!
Take one of the solder jump off and add a resistor in there, you will be able to drop that voltage. the frequency might change a bit and you will have to adjust the turn count.
teh array on the left are to put resistor and capa but when not used, they act as stub witch can cause isue with tuning so i broke the traces on yours as a tester.
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Every individual proxmark3 easy seems to have different measurements… Likely due to poor tolerances and undocumented impromptu part swaps during manufacture. Also brokers often mix various manufacturer output streams together.
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That’s more likely the case over poor tolerances.
Chances are that there are many different board designs that look similar but are not compatible with each other.
You should see what I have seen in chinise designs… I wonder if chinise students read Mao in their electronics classes…
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Don’t underestimate poor tolerances… I’ve ordered plenty of Chinese 5% parts that have been as high as 20% out of spec… not to mention a ton of these parts are totally Chinese factory specials with no sku or part number… just some random parts in a dusty bin some back alley broker supplied.
Even things like quality and purity of the copper used will totally change resistance… and that kind of thing is important in an antenna.
You almost have to expect things to not be what they seem when dealing with a country that invented gutter oil.
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I’ve had worse experiences, but the boards of those Proxmarks appear to fit together well. However, they don’t fit with boards from other Proxmarks or community designs. This is why I think that it’s by design.
The worst case I’ve came across when it comes to poor tolerances, was a bunch of RFP50N06 mosfets that were an order of magnitud off spec.
True…
So I tried a 100Ω resistor. That brought the voltage down quite a bit and increased the Q factor quite a bit. However, I was not able to get it to read the implant at all. Interestingly, the firmware warning disappeared.
Next I tried a 47Ω resistor. Higher voltage and lower Q than 100Ω as expected. The warning has returned too. Unfortunately still no reads though.
I’ve double checked that can still read a T5577 fob on the PM3 and that I can read my implant on my flipper, just to rule out any any issues there.
Should I keep going with different resistors? Or should I roll the QC dice on another PM3?
If the math is slightly off and you’re getting weird warnings, then it’s probably because of manufacturing tolerances.
Dangerous Things is probably your best bet if you want good QC on a Proxmark3 Easy. Amal checks them, adds solder to the weak spots, flashes the latest Iceman firmware, etc…
There’s also the Proxmark3 RDV4 which is smaller and you know exactly what you are getting, but it’s significantly more expensive. Even if it’s still cheaper than buying 5 Easys.
And there’s a fancy LF implant antenna available for the RDV4.