Description : What range of frequencies are usually referred to as the UHF Band? w) 3 to 30 Megahertz x) 30 to 300 Megahertz y) 300 to 3,000 Megahertz z) 30,000 to 300,000 Megahertz
Last Answer : ANSWER: Y -- 300 TO 3,000 MEGAHERTZ
Description : At frequencies above 100 megahertz, the intrinsic (i) region causes a pin diode to act as what?
Last Answer : Variable resistance.
Description : What type of polarization should be used if an antenna is mounted on a moving vehicle at frequencies below 50 megahertz?
Last Answer : Vertical polarization.
Description : It is known that WWV operates on a frequency of 10 megahertz. What is the wavelength of WWV?
Last Answer : 30 meters.
Description : If the fundamental frequency is 200 megahertz, what is the third harmonic?
Last Answer : 600 megahertz.
Description : What IF frequencies are normally used in radar receivers
Last Answer : Thirty or sixty megahertz.
Description : For AM transmissions, the carrier is normally modulated within what range?
Last Answer : 60% to 95%.
Description : The full range of VHF frequencies used for communications is: a. 3 to 30 MHz b. 88 to 108 MHz c. 108.0 to 139.95 MHz d. 118.0 to 136.975 MHz
Last Answer : d. 118.0 to 136.975 MHz
Description : What range of frequencies are usually referred to as the Ultra High Frequency (UHF) Band? w) 3 to 30 Mega Hertz x) 30 to 300 Mega Hertz y) 300 to 3,000 Mega Hertz z) 30,000 to 300,000 Mega Hertz
Last Answer : ANSWER: Y -- 300 to 3,000 MEGA HERTZ
Description : What range of frequencies are usually referred to as audio frequencies for humans? w) 0 to 20 Hertz x) 20 to 20,000 Hertz y) 200 to 200,000 Hertz z) 10,000 to 30,000 Hertz
Last Answer : ANSWER: X -- 20 TO 20,000 HERTZ
Description : What is an advantage of using horizontal polarization at high frequencies?
Last Answer : Less interference is experienced by man-made noise sources
Description : What is the WAVELENGTH of the carrier wave, in meters, of a radio station which is broadcasting at a frequency of 100 megahertz?
Last Answer : ANSWER: 3 METERS
Description : Which of the following frequencies is normally used for distress and safety communications? A. 4209.5 kHz B. 490 kHz C. 518 kHz D. 2174.5 kHz
Last Answer : D. 2174.5 kHz
Description : What type of insulator works well at very high frequencies?
Last Answer : A shorted quarter-wave section called a metallic insulator.
Description : At very high frequencies, what characteristics are displayed by ordinary insulators?
Last Answer : The characteristics of the dielectric of a capacitor.
Description : . Why are coaxial lines more efficient at microwave frequencies than two-wire transmission lines?
Last Answer : The electromagnetic fields are completely confined
Description : A cavity that vibrates at its natural frequency produces a louder sound than at other frequencies. What term is used to describe this phenomenon?
Last Answer : Resonance.
Description : What type filter is used to block the passage of current for a narrow band of frequencies, while allowing current to flow at all frequencies above or below this band?
Last Answer : . Band-reject.
Description : What type filter is used to allow a narrow band of frequencies to pass through a circuit and attenuate all other frequencies above or below the desired band?
Last Answer : Bandpass.
Description : What term is used to describe the frequency at which the filter circuit changes from the point of rejecting the unwanted frequencies to the point of passing the desired frequencies?
Last Answer : Frequency cutoff (fco).
Description : What is the filter called that passes low frequencies but rejects or attenuates high frequencies?
Last Answer : Low-pass filter, high-frequency discriminator or high-frequency attenuator.
Description : What is the filter called in which the low frequencies do not produce a useful voltage?
Last Answer : High-pass filter, low-frequency discriminator, or low-frequency attenuator.
Description : What is the device called that will separate alternating current from direct current, or that will separate alternating current of one frequency from other alternating currents of different frequencies?
Last Answer : A filter.
Description : What is the band of frequencies called that is included between the two points at which current falls to 70 percent of its maximum value in a resonant circuit?
Last Answer : Bandwidth of the circuit
Description : What effect does transit time have on a conventional triode operated at uhf frequencies?
Last Answer : It causes the control grid to short to the cathode
Description : How does fog affect radio waves at frequencies above 2 gigahertz?
Last Answer : It can cause attenuation by absorbtion.
Description : When a wide band of frequencies is transmitted simultaneously, each frequency will vary in the amount of fading. What is this variable fading called?
Last Answer : Selective fading.
Description : Receiver bandwidth is defined as those frequencies spread between what two points of the receiver response curve?
Last Answer : Half-power points.
Description : What transmitter component allows the radiation of a large number of discrete frequencies over a wide band?
Last Answer : . Frequency synthesizer.
Description : Why do 2D air-search radars use relatively low carrier frequencies and low pulse-repetition rates?
Last Answer : Increased maximum range.
Description : Is it possible for a transmission line to operate improperly at certain frequencies and properly at others?
Last Answer : Yes, it is quite common.
Description : What device sweeps a band of frequencies to determine frequencies and amplitudes of each frequency component?
Last Answer : Spectrum analyzer.
Description : The cavities of a multicavity klystron are tuned to slightly different frequencies in what method of tuning?
Last Answer : Stagger tuning.
Description : How does transit time affect the relationship of the grid voltage and the plate current at high frequencies?
Last Answer : Transit time causes the grid voltage and plate current to be out of phase
Description : What frequencies are provided through the back-panel BNC?
Last Answer : 1 MHz and 10 MHz.
Description : What type of polarization should be used at medium and low frequencies?
Description : What circuit section is required in the output of a multivibrator modulator to eliminate unwanted output frequencies?
Last Answer : An LCR filter.
Description : With a single modulating tone, what is the amplitude of the sideband frequencies at 100-percent modulation?
Last Answer : One-half the amplitude of the carrier.
Description : What type of coupling is most effective at high frequencies?
Last Answer : Impedance coupling.
Description : What is the approximate range of frequencies that humans can hear?
Last Answer : Answers is the place to go to get the answers you need and to ask the questions you want
Description : In what range of frequencies are most omnidirectional horizontally polarized antennas used? A. VHF, UHF B. VLF, LF C. SH, EHF D. MF, HF
Last Answer : A. VHF, UHF
Description : What noise is observable at frequencies in the range from about 8 MHz to somewhat 1.5 GHz? A. Industrial noise B. Atmospheric noise C. Space noise D. Shot noise
Last Answer : C. Space noise
Description : The following are true about the contrast sensitivity: a. Pelli-Robson chart tests the contrast sensitivity b. is a measure of the ratio of brightness to darkness c. a contrast of 1 means that there is no contrast d. is highest at middle range frequencies
Last Answer : is highest at middle range frequencies
Description : The full range of VHF frequencies used for communication is:
Last Answer : 118.0 to 136.975
Description : X-rays that are emitted in all directions and with a continuous range of frequencies are known as a) characteristic X-rays b) continuous X-rays c) scattered X-rays d) stimulated X-rays.
Last Answer : b) continuous X-rays
Description : The range of frequencies used in induction heating is : (A) 0-25 Hz (C) less than 200 Hz (B) 50 to 100 Hz (D) more than 1 kHz
Last Answer : The range of frequencies used in induction heating is : more than 1 kHz
Last Answer : Frequencies in the UHF range propagate by means of space wave.
Description : For a continuous flow type of sedimentation tanks A. Width of the tank is normally kept about 6 m B. Length of the tank is normally kept 4 to 5 times the width C. Maximum horizontal flow velocity is limited to 0.3 m/minute D. All the above
Last Answer : ANS: D
Description : At what distance is VHF propagation normally limited? A. Around 500 miles B. Around 1500 miles C. Around 2000 miles D. Around 1000 miles
Last Answer : A. Around 500 miles