- rocket exhaust
- rod antenna
- roger
- roll control
- roll in
- roof antena
- roof aerial
- room noise
- rotatable polarizer
- room reverberation
- room temperature
- root test
- rotatable antenna
- rotating goniometer
- rotating mechanism
- rotational symmetry
- rough tuning
- rounded pulse
- route calls
- route group
- routine check
- routing code
- routing information
- routing ladder
- routing plan
- running heading
- s-band
- safety standards
- sag
- routine component
- routine maintenance
- routing check
- routing control
- routing data
- routing indicator
- routing prefix
- routing table
- RQ cycle
- runway
- running state
- rural network
- safety band
- safety communication
- salary differential
- salary increment
- salary range
- salary survey
- root director
- rotary exchange
- rotary system
- round angle
- route congestion
- routine test
- routing centre
- routing key
- routing translator
- rubidium maser
- ruby laser
- ruin problem
- run time
- rural switch
- safelight
- safety call
- safety frequency
- safety margin
- salary advance
- sample point
- sample program
- sample pulses
- sampled data
- sampled signal
- sampled value
- sampling amplifier
- sampling location
- sampling machine
- sampling structure
- sand time
- sapphire substare
- satellite antenna
- satellite drift
- satellite exchange
- satellite failure
- satellite link
- satellite position
- satellite surface
- satellite transponder
- saturated fluorescence
- saturated logic
- saturated transistor
- saturation point
- saxophone
- scanning cycle
- scanning range
- scattered radiation
- scattering phenomenon
- scatterometer
- Schottky TTL
- scientific payload
- sand reel
- satellite change