Thanks to a few dedicated community members
Notably @Hamspiced and @Satur9
There are now a number of resonant repeaters for us to choose from.
I have carried out independent testing on a variety of repeaters, and the below serves to document my findings for you to make your own decision as to what will suit your own scenario.
For the purposes of clarity, I have broken the testing down into 3 Categories
Large Form Factor - Small Form Factor - Sticker Form Factor
Previous similar tests, I carried out with:
My Phone, A PM3 Easy, A PM3 RDV4 and a Flipper.
Due to [considerations, blah blah decisions blah blah, explained, deleted, boring] this round of testing I have chosen to simply use:
EQUIPMENT
- Vector Network Analyzer
- Flipper Zero
TARGET
The target was an OG copper antenna FlexM1 (chinese knock off)
PROCESS
-
The average was taken over 5 tests on each repeater.
*The repeater placed on reader and “implant” presented to reader. using my test rig.
-
I used hammys Diagnostic Discs to find the sweet spot.
BASELINE MEASUREMENT
(No Repeater)
FLIPPER 
FlexM1
20mm
LARGE FORM FACTOR
V2.1 - Larger sized repeater
42mm
13.959MHz
NFC Amplifier V3L
42mm
13.56Mhz
SMALL FORM FACTOR
25mm
13.5MHz
RFID Antenna Adapter for Tuning Antennas
Flex model is the thinnest possible for tight spaces and needs.
PCB’s come bare, you will need to supply your own Antenna coil and capacitor
25mm
13.56MHz
STICKER FORM FACTOR
(testing was carried out on 4 stickers of each offering)
Flex NFC Repeaters 13.56mhz Range Extenders
25mm
13.35MHz
DT Sticker pack
10mm
12.78MHz
My personal picks/ recommendations
-
Large Form Factor
If you have the space, go for a Large Form Factor
To me there was no discernable performance factor between the V2.1L or the V3.0.
But the V3.0 is Sleek having no protruding components.
GREAT for a desk reader mounted under a desk, you could even place the V3.0 on the top surface of the desk as functional eye candy.
and it is tuned BANG ON!!! -
Small Form Factor
They all provide an improvement, so you can’t go wrong.
The decision will depend on where you want to use it -
Sticker Form Factor
Hammys stickers are what I am using and I am super happy with them
BONUS CONTENT
Curiosity test - Field detector = 23mm
