====== radio ======

===== ramp up time =====

  * fast ramp-up 40us (from disabled state)
  * turn around >20us possible without ''disabled'' state: [[https://devzone.nordicsemi.com/f/nordic-q-a/17999/nrf5x-radio-state-transition-from-transmit-to-receive-ramp-up|nRF5x radio state transition from transmit to receive, ramp up]]