300 QUESTION BOARD EXAM REVIEWER PART1

Question 1

What is the opposition to the transfer of energy, which is considered the dominant characteristic of a cable or circuit that emanates from its physical structure?

Answer 1

Impedance

Question 2

2. When load impedance is equal to characteristic impedance of the line, it means that the load _____ all the power.

Answer 2

Absorbs

Question 3

3. Impedance matching ratio of a coax balun (balancing unit).

Answer 3

4:1

Question 4

Which stands for dB relative level?

Answer 4

dBr

Question 5

Standard test tone used for Audio measurement?

Answer 5

1000Hz or 1KHz

Question 6

When VSWR is equal to zero, this means?

Answer 6

No power is applied

Question 7

_____ is the ratio of reflected voltage to the forward travelling voltage?

Answer 7

Reflection coefficient

Question 8

Transmission lines must be matched to the load to _____

Answer 8

transfer maximum power to the load

Question 9

Which indicates the relative energy loss in a capacitor?

Answer 9

Dissipation factor

Question 10

What is the standard test tone?

Answer 10

0 dBm (decibel relative to milliwatt), 1mW

Question 11

The energy that neither radiated into space nor completely transmitted.

Answer 11

Standing waves

Question 12

Micron is equal to _____ meter.

Answer 12

10^-6

Question 13

1 Angstrom is equal to ______ meter.

Answer 13

10^-10

Question 14

Why is it impossible to use a waveguide at low radio frequencies?

Answer 14

Because of the size of the waveguide

Question 15

_____ is the transmission and reception of information

Answer 15

Communications

Question 16

What is the loss of the circuit if the power ratio of output to input is 0.01?

Answer 16

-20 (20 answer in calculator, but if input is greater than output, 1/100 = 0.01, then there is loss, formula is dBp=10log(I/O))

Question 17

Transmission lines are either balanced or unbalanced with respect to?

Answer 17

Ground

Question 18

The standing wave ratio is equal to _____ if the load is properly matched.

Answer 18

1

Question 19

_____ is the advantage of the balanced transmission line compared to unbalanced transmission line.

Answer 19

Low attenuation

Question 20

_____ is the method of determining the bandwidth of any processing system.

Answer 20

Spectral Analysis

Question 21

What causes the attenuation present in a waveguide?

Answer 21

Losses in the conducting walls of the guide

Question 22

A device that converts a balanced line to an unbalanced line of a transmission line.

Answer 22

Balun (Balancing Unit / Balanced to Unbalanced)

Question 23

What is the approximate impedance of a parallel-strip line spaced 1cm apart with the length of 50cm?

Answer 23

10 Ohms (length/spacing?)

Question 24

What is the average power rating of RG-58 C/u?

Answer 24

50W

Question 25

A coaxial cable used for high temperatures.

Answer 25

RG-211

Question 26

If you have available number of power amplifiers with a gain of 100 each, how many such amplifiers do you need to give an overall gain of 60dB?

Answer 26

3 amplifiers (dB=10log(Power Input to Output ratio), (20dB = 10log(100))

Question 27

The Velocity factor of the transmission lines depends on _____

Answer 27

the dielectric constant of the material used.

Question 28

Impedance inversion can be obtained by?

Answer 28

A quarter wave line (a half wave, pi/2, will lead to same impedance, admittance is at pi/4 )

Question 29

Transmission lines when connected to the antennas have ______.

Answer 29

Resistive load at the resonant frequency.

Question 30

One of the following is not a bounded media: Coaxial, Two-Wire line, Waveguide, and Ocean.

Answer 30

Ocean

Question 31

The impedance measured at the input of the transmission line when its length is infinite.

Answer 31

Characteristic Impedance (the question is referring to the impedance seen at z=positive infinity, aka at the right most side, aka at the load)

Question 32

The following are considered primary line constants except ______. Conductance, Resistance, Capacitance, Complex Propagation Constant.

Answer 32

Complex Propagation Constant

Question 33

The dielectric constants of materials commonly used in transmission lines range from about?

Answer 33

1.2 to 2.8

Question 34

Typically, the velocity factor of the materials used in transmission lines range from?

Answer 34

0.6 to 0.9

Question 35

For an air dielectric two-wire line, the minimum characteristic impedance value is?

Answer 35

85 Ohms

Question 36

When a quarter-wave section transmission line is terminated by a short circuit and is connected to an RF source at the other end, it’s input impedance is?

Answer 36

Equivalent to parallel resonant LC circuit (Current Max, Impedance Minimum, Voltage Minimum)

Question 37

When a half-wave section transmission line is terminated by a short circuit and is connected to an RF source at the other end, it’s input impedance is?

Answer 37

Equivalent to series resonant LC circuit (Current Min, Voltage Max, Impedance Max)

Question 38

The concept used to make one Smith Chart universal is called?

Answer 38

Normalization

Question 39

What are the basic elements of communications system?

Answer 39

Transmitter, Receiver and Transmission Channel

Question 40

_____ is a continuous tone generated by the combination of two frequencies of 350Hz and 440Hz used in telephone sets.

Answer 40

Call waiting tone

Question 41

_____ is the transmission of printed material over telephone lines.

Answer 41

Facsimile

Question 42

_____ are unidirectional amplifiers having 20-25 dB gain that are placed about 75km apart used to compensate for losses along the telephone line.

Answer 42

VF (Voice Frequency) Repeaters

Question 43

_____ is a component in the telephone set that has the primary function of interfacing the handset to the local loop.

Answer 43

Induction Coil

Question 44

Pulse Dialing has _____ rate

Answer 44

10 pulse per sec

Question 45

______ is a telephone wire that connects two central offices.

Answer 45

Trunk line

Question 46

The central switching office coordinating element for all cell sites that has a cellular processor and a cellular switch. It interfaces with telephone company zone offices, control call processing and handle billing activities.

Answer 46

Mobile Telephone Switching Office (MTSO)

Question 47

_____ in a cellular system performs radio-related functions for cellular site.

Answer 47

Base Station

Question 48

A technology used to increase the capacity of a mobile phone system.

Answer 48

Frequency re-use