433MHz transmitter Coil missing
I received my 433MHz pairs of transmiters and wondered that the little coil on the transmitter was missing (on all 4!)
but at first sight I thinked “why not?”
I tried a lot of example (VirtualWire & RadioHead) and nothing was functionning (I didn’t get a transmission),
- what is this little coil intended for?
- is there an electrical schema to understand it?
- how to make it with simple wire to add it on the board?