Set to true when a message is received. This variable triggers the section registered by the regradio command to handle radio events.
This variable is reset to false automatically when the radio event handle completes. The _radio variable can also be manually reset with the clear command. If no section has been registered to handle radio events and the clear command is not used, _radio will remain true after the first message is received.
_radiocomm, regradio, radiosend, radiochannel, clear