Question 6A395

Self-excited oscillators generate their operating frequency directly from their resonant tank circuit (comprising inductors and capacitors). In a shipboard environment, these components are highly susceptible to changes. Temperature variations, vibrations, and fluctuating power supplies can cause the values of the inductor and capacitor to drift. These changes directly alter the resonant frequency of the tank circuit, leading to significant **frequency instability**. For reliable radio communication, particularly on a moving vessel where consistent signal integrity is critical for distress calls, navigation, or general communication, a stable operating frequency is paramount. A drifting frequency can cause signals to wander out of band or become unintelligible. More modern transmitters use crystal-controlled or synthesized oscillators for vastly superior stability. * **B) Parasitic oscillations:** While possible in any circuit, these are typically design flaws or construction issues rather than an inherent characteristic defining the instability of a self-excited oscillator *type*. * **C) Violent sound intensities:** This is completely irrelevant to the electrical operation of a radio transmitter. * **D) Large capacity:** This term is vague; if referring to capacitance, it's not a general disadvantage of the oscillator *type*. Self-excited oscillators are often simpler and can be quite compact.