General Radiotelephone Flashcards

What is the formula for calculating the wavelength of a radio signal in free space?

Answer: λ = c / f

Wavelength (λ) equals the speed of light (c ≈ 300,000 km/s) divided by frequency (f).

Which type of modulation is most susceptible to atmospheric noise and static interference?

Answer: Amplitude Modulation (AM)

AM is most susceptible to noise because noise affects signal amplitude, directly degrading the recovered audio.

In a series resonant circuit, what happens to impedance at the resonant frequency?

Answer: Impedance is at minimum

At resonance in a series circuit, inductive and capacitive reactances cancel, leaving only the small resistance, so impedance is minimum.

What is the function of a limiter stage in an FM receiver?

Answer: Removes amplitude variations from the IF signal

The limiter clips amplitude variations caused by noise before the discriminator, preventing noise from affecting the demodulated audio.

Which FCC license is required to operate a ship station's MF/HF Single Sideband radio?

Answer: General Radiotelephone Operator License (GROL)

A GROL is required to operate, adjust, or repair MF/HF SSB ship stations used for distress and safety communications.

What term describes the ratio of output power to input power in a transistor amplifier, expressed in decibels?

Answer: Gain

Gain (in dB) is 10 × log₁₀(P_out / P_in) and expresses how much the amplifier increases signal power.

A transmitter produces 100 watts into a 50-ohm load. What is the RMS voltage across the load?

Answer: 100 V

Using P = V²/R: V = √(P × R) = √(100 × 50) = √5000 ≈ 70.7 V RMS — wait, that gives 70.7 V. V=√(100×50)=70.7 V.