🔍 Key Concepts
• Emission designators like J2B and H3E and what each character means
• The difference between carrier, sidebands, and audio tones in radio transmissions
• How many audio tones are typically used in common radioteletype/FSK-style telegraphy modes
💭 Think About
• Look at each option and ask: Is this describing the structure of the RF signal (carrier/sidebands) or the audio/baseband signal (tones)?
• For H3E, recall whether it is a double-sideband AM, single-sideband with reduced carrier, or some other combination—how many sidebands are present?
• For J2B, think about how many distinct audio frequencies (mark and space) are typically used in automatic telegraphy modes carried over SSB.
✅ Before You Answer
• Verify whether an RF carrier is always necessary to convey information, or if some modes use a suppressed or reduced carrier.
• Check a radio reference table for the structure of H3E: does it have one sideband or two? Full, reduced, or no carrier?
• Confirm, from a J2B description, whether the telegraphy signal uses one tone or two distinct tones (e.g., mark and space) in the audio spectrum.