AvdyneAeroservice:.Element #3C 69-Questions

Element #3C....Good luck!...and remember you will be asked 6 questions from this pool.

(E3C1) What is a frequency standard?
1. A well known (standard) frequency used for transmitting certain messages.
2. A device used to produce a highly accurate reference frequency.
3. A device for accurately measuring frequency to within 1 Hz.
4. A device used to generate wide-band random frequencies.
(E3C2) What is a frequency-marker generator?
1. A device used to produce a highly accurate reference frequency.
2. A sweep generator.
3. A broadband white noise generator.
4. A device used to generate wide-band random frequencies.
(E3C3) How is a frequency-marker generator used?
1. In conjunction with a grid-dip meter.
2. To provide reference points on a receiver dial.
3. As the basic frequency element of a transmitter.
4. To directly measure wavelength.
(E3C4) How is a frequency counter used?
1. To provide reference points on an analog receiver dial thereby aiding in the alignment of the receiver.
2. To heterodyne the frequency being measured with a known variable frequency oscillator until zero beat is achieved, thereby indicating what the unknown frequency is.
3. To measure the deviation in an FM transmitter in order to determine the percentage of modulation.
4. To measure the time between events, or the frequency which is the reciprocal of the time.
(E3C5) What is the most the actual transmitter frequency could differ from a reading of 156,520,000-Hertz on a frequency counter with a time base accuracy of+/- 1.0 ppm?
1. 165.2 Hz.
2. 15.652kHz.
3. 156.52 Hz.
4. 1.4652MHz.
(E3C6) What is the most the actual transmitter frequency could differ from a reading of 156,520,000-Hertz on a frequency counter with a time base accuracy of+/- 10 ppm?
1. 146.52 Hz.
2. 10 Hz.
3. 156.52kHz.
4. 1565.20 Hz.
(E3C7) What is the most the actual transmitter frequency could differ from a reading of 462,100,000-Hertz on a frequency counter with a time base accuracy of+/- 1.0 ppm?
1. 46.21 MHz.
2. 10 Hz.
3. 1.0 MHz.
4. 462.1 Hz.
(E3C8) What is the most the actual transmit frequency could differ from a reading of 462,100,000-Hertz on a frequency counter with a time base accuracy of+/- 0.1 ppm?
1. 46.21 Hz.
2. 0.1 MHz.
3. 462.1 Hz.
4. 0.2MHz.
(E3C9) What is a dip-meter?
1. A meter used as a nonradiating load (dummy load) to measure transmitter output power.
2. A meter used to measure the reflection coefficient of an RF transmission path.
3. A variable LC oscillator with metered feedback current.
4. A fixed tuned LC oscillator used to troubleshoot RF tank circuits.
(E3C10) How does a dip-meter function?
1. Reflected waves at a specific frequency desensitize the detector coil.
2. Power absorbed by a resonant circuit causes a decrease in dip-meter current.
3. Power from a transmitter cancels feedback current.
4. Harmonics of the oscillator cause an increase in resonant circuit Q resulting in an increase in transmitter output power.
(E3C11) What two ways could a dip-meter be used in a radio station?
1. To measure resonant frequency of antenna traps and to measure percentage of modulation.
2. To measure antenna resonance and to measure percentage of modulation.
3. To measure antenna resonance and to measure antenna impedance.
4. To measure resonant frequency of antenna traps and to measure a tuned circuit resonant frequency.
(E3C12) How tight should the dip-meter be coupled with the tuned circuit being checked?
1. As loosely as possible, for best accuracy.
2. As tightly as possible, for best accuracy.
3. First loose, then tight, for best accuracy.
4. With a soldered jumper wire between the meter and the circuit to be checked, for best accuracy.
(E3C13) What factors limit the accuracy, frequency response, and stability of an oscilloscope?
1. Sweep oscillator quality and deflection amplifier bandwidth.
2. Tube face voltage increments and deflection amplifier voltage.
3. Sweep oscillator quality and tube face voltage increments.
4. Deflection amplifier output impedance and tube face frequency increments.
(E3C14) What factors limit the accuracy, frequency response, and stability of a D'Arsonval movement type meter?
1. Calibration, coil impedance and meter size.
2. Calibration, series resistance and electromagnet current.
3. Coil impedance, electromagnet voltage and movement mass.
4. Calibration, mechanical tolerance and coil impedance.
(E3C15) What factors limit the accuracy and stability of a frequency counter?
1. Number of digits in the readout, speed of the logic and time base stability.
2. Time base accuracy, speed of the logic and time base stability.
3. Time base accuracy, temperature coefficient of the logic and time base stability.
4. Number of digits in the readout, external frequency reference and temperature coefficient of the logic.
(E3C16) How can the frequency response of an oscilloscope be improved?
1. By using a triggered sweep and a crystal oscillator as the time base.
2. By using a crystal oscillator as the time base and increasing the vertical sweep rate.
3. By increasing the vertical sweep rate and the horizontal amplifier frequency response.
4. By decreasing the minimum rise time of the vertical amplifier.
(E3C17) How can the accuracy of a frequency counter be improved?
1. By using slower gating circuitry and increasing the number of digits used for display.
2. By increasing the amount of time the control gate is held open, more pulses can be counted.
3. By using a crystal controlled oscillator mounted in a thermal oven for the time base.
4. By using faster gating circuitry and decreasing the number of digits used for display.
(E3C18) What is the name of the condition that occurs when the signals of two transmitters in close proximity mix together in one or both of their final amplifiers, and unwanted signals at the sum and difference frequencies of the original transmissions are generated?
1. Amplifier desensitization.
2. Neutralization.
3. Adjacent channel interference.
4. Intermodulation interference.
(E3C19) How does intermodulation interference between two transmitters usually occur?
1. When the signals from the transmitters are reflected out of phase from airplanes passing overhead.
2. When they are in close proximity and the signals mix in one or both of their final amplifiers.
3. When they are in close proximity and the signals cause. feedback in one or both of their final amplifiers.
4. When the signals from the transmitters are reflected in phase from airplanes passing overhead.
(E3C20) How can intermodulation interference between two transmitters in close proximity often be reduced or eliminated?
1. By using a Class C final amplifier with high driving power.
2. By installing a terminated circulator or ferrite isolator in the feed line to the transmitter and duplexer.
3. By installing a band-pass filter in the antenna feed line.
4. By installing a low-pass filter in the antenna feed line.
(E3C21) What will occur when a non-linear amplifier is used with a single-sideband phone transmitter?
1. Reduced amplifier efficiency.
2. Increased intelligibility.
3. Sideband inversion.
4. Distortion.
(E3C22) How can even-order harmonics be reduced or prevented in transmitter amplifier design?
1. By using a push-push amplifier.
2. By using a push-pull amplifier.
3. By operating class C.
4. By operating class AB.
(E3C23) What is receiver desensitizing?
1. A burst of noise when the squelch is set too low.
2. A burst of noise when the squelch is set too high.
3. A reduction in receiver sensitivity because of a strong signal on a nearby frequency.
4. A reduction in receiver sensitivity when the AF gain control is turned down.
(E3C24) What is the term used to refer to a reduction in receiver sensitivity caused by unwanted high-level adjacent channel signals?
1. Intermodulation distortion.
2. Quieting.
3. Desensitizing.
4. Overloading.
(E3C25) What is cross-modulation interference?
1. Interference between two transmitters of different modulation type
2. Interference caused by audio rectification in the receiver preamp.
3. Harmonic distortion of the transmitted signal.
4. Modulation from an unwanted signal is heard in addition to the desired signal.
(E3C26) What is the term used to refer to the condition where the signals from a very strong station are superimposed on other signals being received?
1. Intermodulation distortion.
2. Cross-modulation interference.
3. Receiver quieting.
4. Capture effect.
(E3C27) What is the capture effect?
1. All signals on a frequency are demodulated by an FM Receiver.
2. All signals on a frequency are demodulated by an AM receiver.
3. The strongest signal received is the only demodulated signal.
4. The weakest signal received is the only demodulated signal.
(E3C28) If a strong FM-phone signal and a weak FM-phone signal, both using the same carrier frequency, are received simultaneously, why is only one demodulated?
1. Strong signal desensitizes the receiver circuitry to block the weak signal.
2. Strong signal causes cross-modulation interference to prevent the weaker signal from being received.
3. Strong signal captures the local oscillator preventing the weak signal from being detected.
4. Strong signal forces the receiver RF amps to discriminate against the weaker signal.
(E3C29) How does a spectrum analyzer differ from a conventional oscilloscope?
1. The oscilloscope is used to display electrical signals while the spectrum analyzer is used to measure ionospheric reflection.
2. The oscilloscope is used to display electrical signals in the frequency domain while the spectrum analyzer is used to display electrical signals in the time domain.
3. The oscilloscope is used to display electrical signals in the time domain while the spectrum analyzer is used to display electrical signals in the frequency domain.
4. The oscilloscope is used for displaying audio frequencies and the spectrum analyzer is used for displaying radio frequencies.
(E3C30) What does the horizontal axis of a spectrum analyzer display?
1. Amplitude.