- radio interference
- radio interferometry
- radio link
- radio network
- radio operator
- radio oscillation
- radio path
- radio ray
- radio receiver
- radio room
- radio shielding
- radio signal
- radio sonobuoy
- radio source
- radio spectroscopy
- radio star
- radio station
- radio subscriber
- radio subsystem
- radio teletype
- radio-amplifier
- radio-compass
- radioastronomy antenna
- radioastronomy band
- radioastronomy station
- radiobeacon station
- radiometric technique
- radiospectroscopy
- radiotelegraph circuit
- radioteletype
- radiotelex
- raditechnology
- rain attenuation
- rain scatter
- radiosound antenna
- radiosource
- radiotelegraph certificate
- radiotube
- radix sorting
- radome
- railwayman
- rain cell
- rain factor
- random error
- random instability
- random organization
- random selection
- range finding
- rated power
- rating scale
- ratio control
- rational function
- raw data
- rayleigh fading
- RCTL logic
- re-employment
- reach
- reactance attenuator
- reaction device
- read statement
- read transistor
- reading screen
- raindrop population
- rainfall rate
- ramark
- random component
- random excitation
- random fading
- random hunting
- random movement
- random noise
- random traffic
- range finder
- range marker
- range system
- ranked data
- raster unit
- rate meter
- ray path
- rc
- re-flyable
- reactance chart
- reaction jet
- reaction wheel
- read buffer
- read system
- reading device
- reading gun
- readout station
- rear feed
- receiver board
- receiver diode
- receiver gate
- receiving terminal
- receiving tube
- reception area
- reception level
- random data
- random distribution
- random failure