Generic CC1101 modules for SubGhz
When sourcing a generic module make sure it is the 868/915Mhz version NOT the 433 Mhz version.
The two modules are identical other than component values which are unmarked.
Note: there are major problems with the some generic CC1101 "Green" Modules, i.e.
they don't work!
Always verify that VDD is NOT shorted to ground!
Also check for shorts between the "castellated" pads at the edge of the board.
(Yes the "quality" of some module is that good, you get what you pay for.)
Note: EByte E07-900M10S Modules seem to work without major issues.
There are various CC1101 module with differing pinouts available from the "usual places".
Here are two examples, note the one with a solid white silkscreen on the back seems to be a slightly higher quality than the other version.
It is STRONGLY recommended that you verify the connections to the CC1101 pins rather than making any assumptions.
One popular module used by the Mini V3 and early Mini v4s and Yellow APs has this pinout.
It is known that the most trouble come from the shifted base frequency of such modules https://asksinpp.de/Grundlagen/FAQ/Fehlerhafte_CC1101.html#ermittlung-der-cc1101-frequenz .
OEPL uses a wide receiver bandwidth and the CC1101s frequency error measurement and adjustment to attempt to compensate for inaccurate base frequency caused by cheap crystals.