Letter: r
- radio astronomy, astronomy, astrophysics, spectroscopy, stargazing
- radio beacon, Roman candle, alarm, beacon, beam, bell, blinker, buoy, celestial navigation, chronometer, dead reckoning, fix, flare, foghorn, glance, green light
- radio bearing, aspect, attitude, azimuth, bearing, bearings, celestial navigation, dead reckoning, exposure, fix, frontage, lay, lie, orientation, position, set
- radio compass, compass, direction finder, instrument, needle
- radio control, automatic electronics, bionics, circuit analysis, communication theory, cybernetics, information theory, servo engineering, system engineering, systems analysis, systems planning, telemetry
- radio direction finder, compass, device, direction finder, instrument, needle, radio
- radio drama, Passion play, ballet, bomb, charade, cliff hanger, dialogue, drama, duologue, extravaganza, failure, flop, gasser, give-away, happening, hit
- radio electrician, ham, mixer, monitor, radio operator, radio technician
- radio engineer, engineer, ham, mixer, monitor, radio operator, radio technician
- radio fare, broadcast, commercial, newscast, serial, soap opera, sportscast, sustainer
- radio frequency, RF, UHF, VHF, audio frequency, cycle, frequency, kilocycle, megacycles, spectrum
- radio links, circuit, hookup, net, network
- radio navigation, celestial navigation, chronometer, dead reckoning, fix, navigation, radar, sextant, sonar
- radio observatory, observatory, planetarium, reflector, spectrograph, spectroscope, telescope
- radio operator, amateur radio operator, black gang, bungs, cabin boy, chips, commissary steward, complement, control engineer, deckhand, fireman, gun loader, gunner, ham, hand, hospital steward
- radio range beacon, beacon, radiator, radio transmitter, transmitter
- radio receiver, amplifier, baffle, bypass, cabinet, capacitor, chassis, coil, condenser, console, detector, dial, exciter, filter, heater, heterodyne
- radio relay station, radio station, studio
- radio set, cabinet, chassis, console, housing, radio, radio receiver, receiver, set, wireless
- radio star, black hole, magnitude, nova, population, pulsar, quasar, supernova
- radio station, direction-finder station, radio relay station, studio
- radio technician, amateur radio operator, control engineer, electrician, ham, linesman, mixer, monitor, radio electrician, radio engineer, radio operator, radioman, rigger
- radio telescope, cabinet, chassis, console, device, housing, observatory, planetarium, radio, radio receiver, receiver, reflector, set, spectrograph, spectroscope, telescope
- radio transmitter, amateur transmitter, beacon, coaxial cable, fan marker, frequency meter, microphone, mixer, modulator, monitor, oscillator, radiator, radio beacon, radio range beacon, radiosonde, transceiver
- radio wave, amplitude, carrier, crest, diffraction, electric wave, electromagnetic radiation, electromagnetic wave, frequency, frequency band, frequency spectrum, ground wave, guided wave, high-frequency wave, in phase, interference
- radio, Teletype, advice, adviser, air, announce, announcer, annunciator, authority, automation, avionics, beam, broadcast, broadcast journalism, cabinet, cable
- radio-frequency amplifier, beam, bounce, parts, radio receiver
- radio-phonograph combination, Gramophone, PA, PA system, bitch box, cartridge, intercom, jukebox, monaural system, mono, needle, phonograph, pick-up, record changer, record player, sound truck
- radio-telegraphy, communications, electronics, radio, telecommunication, television, wireless
- radio-telephone, headphone, headset, phone, telephone, wireless
