# Multi-Gigabit Microwave and Millimeter-Wave Wireless CommunicationsRF Cafe Quiz #34

All RF Cafe Quizzes make great fodder for employment interviews for technicians or engineers - particularly those who are fresh out of school or are relatively new to the work world. Come to think of it, they would make equally excellent study material for the same persons who are going to be interviewed for a job. Bonne chance, Viel Glück, がんばろう, buena suerte, удачи, in bocca al lupo, 행운을 빕니다, ádh mór, בהצלחה, lykke til, 祝你好運. Well, you know what I mean: Good luck!

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Note: Some material based on books have quoted passages.

This quiz is based on the information presented in Multi-Gigabit Microwave and Millimeter-Wave Wireless Communications, by Jonathan Wells. Artech House is the publisher.

1.  Which entity is the primary regulatory agency in the world with responsibility for coordinating

shared global use of the radio spectrum?

a)  WWR (World Wide Radio)

b)  GCU (Global Communications Union)

c)  URU (Universal Radio Union)

d)  ITU (International Telecommunication Union)

2.  What is a primary obstacle to FSO (Free Space Optics) terrestrial usage?

a)  Very high attenuation

b)  Nighttime-only operation

c)  Difficulty generating the light

d)  FM radio interference

3.  Which condition causes the least amount of attenuation on electromagnetic signals?

a)  Moist air

b)  Dry air

c)  High wind

d)  Low wind

4.  What is the equation for determining attenuation factor (specific attenuation) due to snow and ice?

(R=snowfall rate in mm/hr, λ=wavelength in mm)

a)  Attenuation Factor = λ/R

b)  Attenuation Factor = λ/R2

c)  Attenuation Factor = λ/R3

d)  Attenuation Factor = [(0.00349*R1.6)/λ4] + [(0.00224*R)/λ]

5.  What is the equation for determining attenuation due to foliage?

(f=frequency in MHz, R=depth of foliage in m)

a)  Loss = 10 log (f2R)

b)  Loss = 20 log (fR)

c)  Loss = 20R log (f)

d)  Loss = 0.2f0.3R0.6

6.  What is a primary feature of a plesiochronous digital hierarchy (PDH) system?

a)  Running in a state where different parts of the network are nearly,

but not quite perfectly, synchronized

b)  Having features discovered in the Plesioic era

c)  Operating in an orthogonally asynchronous state

d)  Using a deterministic hierarchy

7.  What does the image to the right depict?

a)  An NTSC test signal for CATV

b)  256 QAM with phase noise

c)  The whirlpool constellation

d)  RF astigmatism

8.  Which frequencies in the 60 GHz band are allocated by the FCC for unlicensed use?

a)  57 to 64 GHz

b)  Only at 60 GHz

c)  71 to 74 GHz

d)  There are no unlicensed bands at 60 GHz

9.  What is a link budget?

a)  The cost of a communications system

b)  The total link count in a communications system

c)  A fictitious number representing system performance

d)  An accounting of all gains and losses in a communications system

10.  Which city would likely have higher 23 GHz system availability due to weather?

a)  Riyadh, Saudi Arabia

b)  New Your City, USA

c)  Sydney, Australia

d)  Singapore, Singapore

Need some help? Click here for the answers and explanations.