Is it safe to connect both a transmitter and receiver, of the 315 MHz RF Link kits, to the same microcontroller, using the VirtualWire library?
If so, can they share the same antenna for half-duplex operation?
It is safe to connect several wireless devices (being them transmitter and receiver or any combination of them) to the same microcontroller, assuming you know what you are doing and the dedicated digital control pins are properly used for each device.
It is not, however, safe to share any RF circuitry (such as the antenna) between them. If you want to do that, at the very least you will need RF Switch with proper termination to redirect RF signal to the same antenna from each device. It is certainly easier if you use dedicated antenna for each one.
Hope this helps.
Thanks a lot.
Can I ask another RF question? I want to use an SMD quarter wavelength ground plane antenna. Is it good design to just connect it to the same ground plane that is used by the rest of the board? Should I have a completely separate RF ground plane? Or have two ground planes on the board separated by a thin trace? (This is an 8x10 cm board with MCU and a few other chips plus the RF bits.)
In general terms, using the same GND is correct, but you need to be sure all the high speed digital signals are not in the GND path that will go from antenna to RF link. Put some picture of your prototype if you need additional help.
I think I understand. I’m placing the RF link module quite close to the antenna, and other components are at the other end of the board.