HIGHLIGHTED-Microwave-Communications.pdf

D transverse electromagnetic 464 the wavelength of a

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d. Transverse electromagnetic 464. The wavelength of a wave in a waveguide a. Is greater than in free space b. Depends on waveguide dimensions and free space wavelength c. Is inversely proportional to the phase velocity d. Is directly proportional to the group velocity 465. When electromagnetic waves are propagated in a waveguide, they a. Travel along the broader walls of the guide b. Are reflected from walls but not travel along them c. Travel through the dielectric without touching the walls d. Travel along the 4 walls of the waveguides 466. When microwave signals follow the curvature of the earth, this is known as a. Faraday Effect b. Deducting c. Tropospheric Scatter d. Ionospheric Reflection 467. A waveguide mode in which there is no component of electric field in the direction of propagation given in the British European standards. a. H-mode b. E-mode c. TE mode d. M-mode 468. The extra strength needed in order to assure that enough signal reaches the receiving antenna and must be made available to compensate for fades; computed as the difference between the received signal strength and the threshold level a. Fade Margin b. Threshold Level c. Noise Figure d. RSL 469. The use of redundant system to reduce the effects of multipath fading is a. Combining b. Modulation c. Multiplexing d. Diversity 470. A profile graph of the microwave energy path a. Shows the cross section of the earth’s surface b. Determines LOS or site technical feasibility c. Determines the actual clearance, antenna heights and system reliability d. All of the preceding 471. In locating microwave relay stations, the systems designer must consider a. Terrain obstructions and reflection points b. Site security and navigational hazards c. Availability of power, water source and accessible roads d. All of the above 472. A microwave path over which radio waves barely touches the obstruction is called a. Line of Sight b. Obstructed Path c. Grazing Path d. Crooked Path 473. What is the function of regenerative repeater? a. To eliminate bias distortion b. To help in the loading of the telegraphs lines c. To reduce required signal levels d. To reshape the pulses after they have become distorted 474. A situation when there is no change in attenuation or “no gain, no loss” occurs when ________ % of the first Fresnel radius clears a path obstruction in microwave systems. a. 45% b. 60% c. 75%
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d. 85% 475. ____________ are concentric circular zones about a direct path of a microwave signal called Huygen’s radiation center, forming an imaginary solid called an ellipsoid __________. a. Temperature zone b. Skip zone c. Fresnel zone d. Fraunhoffer zone 476. Waveguides are used mainly for microwave transmission because a. They depend on straight line propagation b. Losses are heavy at lower frequencies c. They are bulky at lower frequencies d. No generator is powerful enough to excite them 477. A waveguide assembly that lets the radar
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