RFID Field Detectors
Originally, I saw a cheap field detector on Aliexpress, and I thought I would give it a try.
I then thought I should put together a quick review, THEN I thought, well I actually have a few different ones I should review them all together
So here we are
DT Diagnostic Card
USD$20 or Free $ with DT implant
X Field Detector
USD$15ea or Free $ with DT implant
Proxgrind RF Field detector
USD$15
RFID Field Detector
USD $10
Results ( I will let the figures speak for themselves )
Green Indicates the best performer in that test
Summary:
Dangerous Things RFID Diagnostic Card
Find out frequency and duty cycle of any passive LF/HF reader!
- Indicates both 125kHz and 13.56MHz fields
- Determine duty cycle (how often the field is on)
- Check field strength through LED intensity
- Fits snugly in any wallet or purse
X Field Detector
The X Field Detector is designed to show the ideal location, rotation, and orientation to position one of our x-series chips when presenting to a reader.
- Indicates both 125kHz and 13.56MHz fields
- Determine duty cycle (how often the field is on)
- Check field strength through LED intensity
- Keyring form factor
RF Detector by ProxGrind
The LF coil has high Q, high sensitivity and long luminescence distance using 6-layer plate technology. HF uses a diode voltage doubler circuit, high sensitivity, long luminous distance.
LF and HF are placed in the smallest volume without weakening, to ensure the best performance in small size. Using epoxy resin to drop glue craft, ten years is like a new, waterproof and moistureproof, wear-resisting and fall-resistant, can carry.
RFID Field Detector
Used to identify the presence of an RFID field. You can easily identify the frequency and unknown reader is operating at.
- 13.56mhz high frequency or nfc reader
- 125khz low frequency reader
Conclusion
The AliExpress RFID Field Detector, is a piece of shit 
and we can write that off right from the start.
Note: They claim " Form factor that fits in your wallet! " Technically true, but it is about 4 times the thickness of the DT Diagnostic Card.
The xFDs are the perfect tool for testing anything xSeries related and there are no other options on the market I am aware of.
The Proxgrind “keyring” style performed better than expected, it is approximately 33% the area of the DT Diagnostic card HOWEVER it is approximately 66% thicker.
They performed quite similarly, with the DT card just nudging out the Proxgrind in more areas.
But in reality, If you had to decide between the two, it would probably come down to form factor and price.
Form Factor and Price
DT Diagnostic card if you prefer to carry in your Wallet (USD$20 or Free $ with DT implant)
Proxgrind if you prefer a Keyring (USD$15)
Polls
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Price
DT Diagnostic Card
USD$20 or Free $ with DT implant
X Field Detector
USD$15ea or Free $ with DT implant
Proxgrind RF Field detector
USD$15
RFID Field Detector
USD $10
