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 : 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 method of diversity reception where the signal is transmitted on 2 different frequencies over the same path? A. Quadruple B. Frequency C. Polarization D. Space
Last Answer : B. Frequency
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 : Why do 2D air-search radars use relatively low carrier frequencies and low pulse-repetition rates?
Last Answer : Increased maximum range.
Description : Rotating the plane of polarization of a wavefront by passing it through a ferrite device is called what?
Last Answer : . Faraday rotation.
Description : What is the polarization of the energy radiated by a vertical slot?
Last Answer : Horizontal.
Description : Describe three ways to prevent polarization.
Last Answer : Vent the cell, add a material rich in oxygen, and use a material that will absorb hydrogen.
Description : Describe three ways to prevent polarization
Last Answer : vent the cell, add a material rich in oxygen, and use a material that will absorb hydrogen.
Description : If a wave's electric lines of force rotate through 360 degrees with every cycle of rf energy, what is the polarization of this wave?
Last Answer : Circular polarization.
Description : The direction of what field is used to designate the polarization of a wave?
Last Answer : Electric (E) field.
Description : .In electromagneticwaves,polarization a. is caused by reflection b.isdue to the transversenature ofthewaves c. results from the longitudinal nature of the waves d. is always vertical in an isotropic medium
Last Answer : b.isdue to the transversenature ofthewaves
Description : What type of insulator works well at very high frequencies?
Last Answer : A shorted quarter-wave section called a metallic insulator.
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 type of coupling is most effective at high frequencies?
Last Answer : Impedance coupling.
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 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 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 IF frequencies are normally used in radar receivers
Last Answer : Thirty or sixty megahertz.
Description : What transmitter component allows the radiation of a large number of discrete frequencies over a wide band?
Last Answer : . Frequency synthesizer.
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 : At frequencies above 100 megahertz, the intrinsic (i) region causes a pin diode to act as what?
Last Answer : Variable resistance.
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 : When using frequencies above 30 megahertz, you are normally limited to using what range?
Last Answer : Line of sight.
Description : What frequencies are provided through the back-panel BNC?
Last Answer : 1 MHz and 10 MHz.
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 : Electrical machinery insulation will break down more rapidly due to _________________. A. low loading of motors and generators B. frequent megger testing C. high temperatures and vibration D. high operating frequencies
Last Answer : Answer: C
Description : Which of the following low noise transistors is commonly used at microwave frequencies? A. MOSFET B. GASFET C. MESFET D. JFET
Last Answer : C. MESFET
Description : A porous material is far more efficient at high than low frequency absorption. How to improve sound absorption at lower frequencies using this absorber? A. Increase the thickness B. Decrease the thickness C. Mount with and airspace behind D. Both A and C above
Last Answer : D. Both A and C above
Description : The ___________ filter attenuates signals but passes frequencies below and above that band. A. low pass B. band pass C. band stop D. high pass
Last Answer : C. band stop
Description : An oscillator that uses crystal control should be A) Frequency stable B) useful only at low frequencies C) AVFO D) none of the above.
Last Answer : A) Frequency stable
Description : The band of light frequencies that are too low to be seen by the human eye ∙ A. Infrared ∙ B. X-rays ∙ C. Visible ∙ D. Ultraviolet
Last Answer : Ultraviolet
Description : One of the potential health effects of exposure to high levels of noise is called tinnitus (pron: ti - NI - tes), which means: w) a permanent loss of hearing. x) a persistent ringing ... ) a temporary loss of hearing, especially of upper frequencies. z) abdominal discomfort from low frequency noise.
Last Answer : ANSWER: X -- A PERSISTENT RINGING OR HISSING IN THE EARS AFTER EXPOSURE.
Description : In electronic circuits, what name is given to a frequency discriminating network designed to select or pass certain bands of frequencies with low attenuation and cause very high attenuation to other frequencies?
Last Answer : ANSWER: FILTER
Description : At very low frequencies a series R-C circuit behaves as almost purely?
Last Answer : At very low frequencies a series R-C circuit behaves as almost purely capacitive.
Description : A refracted wave occurs when a wave passes from one medium into another medium. What determines the angle of refraction?
Last Answer : The density of the two mediums, and the velocity of the waves.
Description : What is the meaning of the term recording medium as it pertains to magnetic recording?
Last Answer : A recording medium is any material that has the ability to become magnetized, in varying amounts, in small sections along its entire length.
Description : What condition causes a light ray to be totally reflected back into its medium of propagation?
Last Answer : Total internal reflection occurs when the angle of refraction approaches 90 degrees. This condition occurs when the angle of incidence increases to the point where no refraction is possible.