Love this picture, one of the funniest product photos I’ve seen
INTRODUCTION
These field meters are tuned to detect any standing NFC field. They will display a value of 1/10vm or 1mH (megaHammy).
They come in 4 different colors (Red, Orange, Blue, Green) that will be selected at random. (if you put in your order notes prefference i will do my best to accomodate).
I cannot guarantee accuracy. But i can guarantee that the meters are accurate to themselves. Meaning each meter will display the same value across each other. If in the future i can get my hands on more precise NFC field testing equipment i can zero these in more and will update with future version releases.
• Can be used like a field detector for optimum placement of implants of Repeater stickers
• .stl for case already available
CONs
Can’t measure phones (that is more of a failure of the phone, not the Field meter)
Fragile, due to exposed components (i personally like that look and feel)
CR2032 that will not be included
( I was struggling to find fault, its a simple fix, and no alternative due to shipping regulations) But its like getting a toy at christmas without batteries, So make sure you have a 2032 handy
PRICE
USD$50
BUT
SUMMARY:
A thing that didn’t exist, now does. (Thanks Hammy)
We can now measure and see the field strength of a variety of readers, allowing you to compare readers to visually determine if a reader could likely work with an implant , which adds another tool for fault finding to our RFID toolbox.
Locate antennas and find best placement for implants and/or repeaters
I am really disappointed that I couldn’t get this digital version to measure field with low duty cycles so I’m working quick to get a version out that will have both an analogue meter and digital meter so you can more precisely take measurements of all devices. The hold up I have is waiting on a supplier to send me some of the actual analogue meters so I can get measurements for assembly holes.
Once those come in it will be a pretty quick turn around for me to get a version of this out that can measure phones, most battery powered readers and low powered devices.
But with that aside I’ve had a lot of fun playing with this.
So this is interesting but it also explains what we see with attempting to use two repeaters.
The field meter is tuned and adding a repeater is like trying to put two repeaters in line. If you turn the meter off and throw a field detector on top you’ll see it actually acts just like a repeater. I’ve not tried this but I’m curious what a VNA would read with the repeater and field meter in line. I’m betting the field gets offset at least a mhz or two.
Guys it doesn’t focus really… it repeats. It literally absorbs field and in doing so;
slightly modifies the shape of the field emitted from the device (reader/source)
inducting power from the source field generates its own ts own magnetic field
the target (NFC transponder) couples with this secondary field
if the target is close to the repeater it will couple with both fields, but they are offset from each other and will cause interference which results in overall reduction of power transfer
This is why the hw tune proxmark3 command is broken with the booster installed.
= 
result.