🔍 Key Concepts

• Harmonics are multiples of the transmitter’s fundamental frequency • How radio-frequency interference can affect nearby electronic equipment • How ionospheric skip (skywave) can make a fundamental frequency inaudible at certain ranges

💭 Think About

• Think about what a harmonic is in relation to the main (fundamental) transmitting frequency. Where in the spectrum do harmonics fall? • Could those harmonic frequencies be received in places or by devices that are not intended to receive the original signal? • Consider whether interference is limited to the radio path only, or whether it can also appear inside other equipment on the same vessel.

✅ Before You Answer

• Check whether harmonic frequencies can travel and be received even when the fundamental frequency is not heard because of propagation conditions like skip. • Ask yourself if high-power transmitters can induce unwanted currents or signals in other shipboard electronics (radar, nav gear, audio systems, etc.). • Before choosing, verify whether interference is restricted to only one situation described, or could logically apply to both situations mentioned in the options.