Key Topic 40: Transmission Lines Flashcards
8-40E1: The VSWR of a microwave transmission line device might be measured using:
A. A dual directional coupler and a power meter.
B. A network analyzer.
C. A spectrum analyzer.
D. A dual directional coupler, a power meter, and a network analyzer.
D. A dual directional coupler, a power meter, and a network analyzer.
8-40E2: The impedance total (Zo) of a transmission line can be calculated by Zo = sqrt{L/C} when L and C are known. When a section of transmission line contains 250 microhenries of L and 1000 picofarads of C, its impedance total (Zo) will be:
A. 50 ohms.
B. 250 ohms.
C. 500 ohms.
D. 1,000 ohms.
C. 500 ohms.
8-40E3: If long-length transmission lines are not properly shielded and terminated:
A. The silicon crystals can be damaged.
B. Communications receiver interference might result.
C. Overmodulation might result.
D. Minimal RF loss can result.
B. Communications receiver interference might result.
8-40E4: A certain length of transmission line has a characteristic impedance of 72 ohms. If the line is cut at its center, each half of the transmission line will have a Zo of:
A. 36 ohms.
B. 144 ohms.
C. 72 ohms.
D. The exact length must be known to determine Zo.
C. 72 ohms.
8-40E5: Standing waves on a transmission line may be an indication that:
A. All energy is being delivered to the load.
B. Source and surge impedances are equal to Zo and ZL.
C. The line is terminated in impedance equal to Zo.
D. Some of the energy is not absorbed by the load.
D. Some of the energy is not absorbed by the load.
8-40E6: What precautions should be taken with horizontal waveguide runs?
A. They should be sloped slightly downwards at the elbow and a small drain hole drilled in the elbow.
B. They should be absolutely level.
C. They should not exceed 10 feet in length.
D. None of the above.
A. They should be sloped slightly downwards at the elbow and a small drain hole drilled in the elbow.
