b. dBa c. dBr d. dBx ans: c Standard test tone used for audio measurement. a. 800 Hz b. 300 Hz c. 100 Hz d. 1000 Hz ans: d When VSWR is equal to zero, this means a. that no power is applied b. that the load is purely resistive c. that the load is a pure reactance d. that the load is opened ans: a ___________ ___________ is the ratio of reflected voltage to the forward traveling voltage. a. SWR b. VSWR c. Reflection coefficient d. ISWR ans: c

b. dBa c. dBr d. dBx ans: c Standard test tone used for audio measurement. a. 800 Hz b. 300 Hz c. 100 Hz d. 1000 Hz ans: d When VSWR is equal to zero, this means a. that no power is applied b. that the load is purely resistive c. that the load is a pure reactance d. that the load is opened ans: a ___________ ___________ is the ratio of reflected voltage to the forward traveling voltage. a. SWR b. VSWR c. Reflection coefficient d. ISWR ans: c

Transmission line must be matched to the load to __________. __________. a. transfer maximum voltage to the load b. transfer maximum power to the load c. reduce the load current d. transfer maximum current to the load ans: b Which indicate the relative energy loss in a capacitor? a. Quality factor b. Reactive factor c. Dissipation factor d. Power factor ans: c What is the standard test tone? a. 0 dB b. 0 dBW c. 0 dBm d. 0 dBrn ans: c The energy that neither radiated into space nor completely transmitted. a. Reflective waves b. Captured waves

c. Incident Incident waves d. Standing waves ans: d Micron is equal to _____________ _____________ meter. a. 10^ -10 b. 10^ -9 c. 10^ -6 d. 10^ -3 ans: c 1 Angstrom (A^ 0) is equal to ___________. ___________. a. 10^ -3 micron b. 10^ -10 m c. 10^ -6 micron d. 10^ -6 m ans: b Why is it impossible to use a waveguide at low radio frequencies? a. Because of the size of the waveguide b. Due to severe atte nuation c. Due to too much r adiation d. All of these ans: a -

__________ is the transmission transmission and reception of information. information. a. Modulation b. Communications c. Radiation d. Emission ans: b What is the loss of the circuit c ircuit in dB if the power ratio o f output to input is 0.01? a. 20 b. -20 c. 40 d. -40 ans: a Transmission lines are either balanced or unbalanced with respect to a. negative terminal b. reference c. ground d. positive terminal ans: c The standing wave ratio is equal to ____________ if the load is properly matched with the transmission line. a. infinity b. 0 c. -1

d. 1 ans: d __________ is the advantage of the balanced transmission line compared to unbalanced line. a. Low attenuation b. Easy installation c. Low radiation loss d. Tensile strength ans: a __________ is the method of determining the bandwidth of any processing system. a. Fourier series b. Spectral analysis c. Frequency analysis d. Bandwidth analysis ans: b What causes the attenuation present in a waveguide? a. The air dielectric filling the guide b. The coating of silver inside c. Losses in the conducting walls of the guide d. Radiation loss ans: c A device that converts a balanced line to an unbalanced line of a transmission line.

a. Hybrid b. Stub c. Directional coupler d. Balun ans: d What is the approximate line impedance of a parallel-strip line spaced 1 cm apart with the length of 50 cm? a. 10 ohms b. 15 ohms c. 18 ohms d. 23 ohms ans: a What is the average power rating of RG-58 C/u? a. 25 W b. 50 W c. 75 W d. 200 W ans: b A coaxial cable used for high temperatures. a. RG-58C b. RG-11A c. RG-213 d. RG-211A

ans: d If you have available number of power amplifiers with a gain o f 100 each, how many such amplifiers do you need to cascade to give an overall gain of 60 dB? a. 2 b. 3 c. 4 d. 5 ans: b You are measuring noise in a voice channel at a -4 dB test point level, the meter reads -73 dBm, convert the reading into dBmCO. a. 12 b. 16 c. 18 d. 22 ans: d The velocity factor of a transmission line a. depends on the dielectric constant of the material used b. increases the velocity along the transmission line c. is governed by the skin effec t d. is higher for a solid dielectric than for air ans: a Impedance inversion can be obtained by

a. a short-circuit stub b. an open-circuited stub c. a quarter-wave line d. a half-wave line ans: c Transmission lines when connected to antennas have a. capacitive load b. resistive load whose resistance is greater than the characteristic impedance of the line c. resistive load whose resistance is less than characteristic impedance of the line d. resistive load at the resonant frequency ans: d One of the following is not a bounded media a. Coaxial line b. Two-wire line c. Waveguide d. Ocean ans: d The impedance measured at the input of t he transmission line when its length is infinite. a. Input impedance b. Open circuit impedance c. Characteristic impedance d. Short circuit impedance

ans: c The following are considered primary line constants except a. conductance b. resistance c. capacitance d. complex propagation constant ans: d The dielectric constants of materials commonly used in transmission lines range from about a. 1.2 to 2.8 b. 2.8 to 3.5 c. 3.5 to 5.2 d. 1.0 to 1.2 ans: a Typically, the velocity factor, V(F) of the materials commonly used in transmission lines range from a. 0.6 to 0.9 b. 0.1 to 0.5 c. 1.0 to 0.9 d. 0.6 to 0.8 ans: a For an air dielectric two-wire line, the minimum characteristic impedance value is a. 85 ohms

b. 83 ohms c. 90 ohms d. 88 ohms ans: b When a quarter-wave section transmission line is terminated by a short circuit and is connected to an RF source at the other end, its input impedance is a. inductive b. capacitive c. resistive d. equivalent to a parallel resonant LC circ uit ans: d A transmitter operating at 30 MHz with 4 W output is connected via 10 m of RG-8A/u cable to an antenna that has an input resistance of 300 ohms. Find the reflection coefficient a. 0.71 b. 0.77 c. 0.97 d. 0.76 ans: a A quarterwave transformer is connected to a parallel wire line in order to match the line to a load of 1000 ohms. The transformer has a char. I mpedance of 316.23 ohms. The dist. Bet. Centers is 4 inches. What is the % reduction in the diameter of the line? a. 85% b. 83% c. 86%

d. 90% ans: b The concept used to make one Smith chart universal is called a. ionization b. normalization c. rationalization d. termination ans: b What are the basic elements of communications system? a. Source, transmission channel, transmitter b. Transmitter, receiver, transmission channel c. Information, transmission channel, receiver d. Sender and receiver ans: b ___________ is the transmission of printed material over telephone lines. a. Internet b. Data communication c. Telegraphy d. Facsimile ans: d ___________ is a continuous tone generated by the combination of two frequencies of 350 Hz and 440 Hz used in telephone sets.

a. DC tone b. Ringing tone c. Dial tone d. Call waiting tone ans: d ___________ are unidirectional amplifiers having 20-25 decibel gain that are placed about 75 km apart used to compensate for losses along the telephone line. a. VF repeaters b. Loading coils c. Loop extenders d. Echo suppressors ans: a ___________ is a component in the telephone set that has the primary function of interfacing the handset to the local loop. a. Resistor b. Capacitor c. Varistor d. Induction coil ans: d Pulse dialing has __________ rate a. 20 pulses/min b. 10 pulses/min c. 10 pulses/sec

d. 80 pulses/sec ans: c ___________ is a telephone wire that connects two central offices. a. 2-wire circuit b. Trunk line c. Leased line d. Private line ans: b The central switching office coordinating element for all cell sites that has cellular processor and cellular switch. It interfaces with telephone company zone offices, control call processing and handle billing activities. a. MTSO b. Cell Site c. PTSN d. Trunk line ans: a ___________ in a cellular system performs radio-related functions for cellular site. a. Switching system b. Base station c. Operation and support system d. Mobile station ans: b -

A technology used to increase the capacity of a mobile phone system. a. Frequency re-use b. Cell splitting c. TDM d. FDM ans: a If the grade of service of a telephone system indicated P = 0.05, what does it mean? a. Completed calls of 5% b. Lost calls of 5% c. Lost calls of 95% d. Lost calls of 105% ans: b ___________ is the Out-of-Band signaling between Toll Central Offices (Bell System Standard) a. 3,825 Hz b. 3700 Hz c. 2,600 Hz d. 800 Hz ans: b In a telephone system, the customer's telephone directory numbering is from 000 to 999, what is the capacity of a telephone system numbering from 000 to 999? a. 100 lines b. 1000 lines c. 10,000 lines

d. 100,000 lines ans: b If the SWR is infinite, what type of load transmission line has? a. Purely reactive b. Purely resistive c. Purely capacitive d. Purely inductive ans: a Not more than _________ digits make up an international telephone number as recommended by CCITT REC. E. 161. a. 8 b. 10 c. 11 d. 12 ans: d One (1) Erlang is equal to _________. a. 360 CCS b. 36 CCS c. 3.6 CCS d. 100 CCS ans: b Standard tariff for flat rate telephone service beyond the normal flat rate in that area.

a. WATS b. OTLP c. TIP d. DTWX ans: a The standard analog telephone channel bandwidth a. 300-3400 Hz b. 1200 Hz c. 200-3200 Hz d. 300-3000 Hz ans: a Type of switching in which a pair of wire from the telephone set terminates in a jack and the switch is supervised by an operator. a. Crossbar switching b. Manual switching c. Electronic switching d. Step-by-step switching ans: b Every time when the telephone is idle, the handset is in the ___________ state. a. on-hook b. off-hook c. busy d. spare

ans: a ___________ is a component in the telephone set that has the primary function of compensating for the local loop length a. Resistor b. Varistor c. Capacitor d. Induction coil ans: b What kind of receiver is used in conventional telephone handset? a. Carbon b. Electromagnetic c. Ceramic d. Capacitor ans: b A voice-grade circuit using the PTN has an ideal passband of a. 0 to 4 Hz b. 0 to 4 MHz c. 0 to 4 kHz d. 0 to 4 GHz ans: c ___________ is the minimum-quality circuit available using the PTN. a. Basic voice grade (VG)

b. Basic voice channel (VC) c. Basic voice band (VB) d. Basic telephone channel ans: a Direct distance dialing (DDD) network is called a. Private-line network b. PT network c. Dial-up network d. Trunk network ans: c What is the advantage of sidetone? a. Transmission efficiency is increased b. Speaker increases his voice resulting in a strengthened signal c. No dissipation of energy in the balancing network d. Assure the customer that the telephone is working ans: d ___________ is a special service circuit connecting two private branch exchanges (PBX). a. Phatom line b. Tie trunk c. Tandem trunk d. Private line ans: b

The published rates, regulations, and descriptions governing the provision of communications service for public use. a. Toll rate b. Tariff c. Bulk billing d. Detailed billing ans: b What is the power loss of a telephone hybrid? a. 1 dB b. 2 dB c. 3 dB d. 6 dB ans: c Telephone channel has a band-pass c haracteristic occupying the frequency range of ___________. a. 300-400 Hz b. 300-3400 Hz c. 300-3000 Hz d. 300-2700 Hz ans: b The first strowger step-by-step switch was used in ____________. a. 1875 b. 1890

c. 1897 d. 1913 ans: c What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees? a. 52 µsec b. 1.25 µsec c. 83.33 µsec d. 26 µsec ans: a What is the CCITT recommendation for a preparation of loss plan, a variable loss plans and a fixed loss plan? a. G.133 b. G.141 c. G.132 d. G.122 ans: d What is the diameter of a copper wire to be used in a 16 km loop with a dc loop resistance of 100 ohms/km? a. 0.838 mm b. 0.465 mm c. 1.626 mm d. 2.159 mm ans: b

What kind of cell is appropriate for load management, fast moving mobiles and low-usage areas? a. Pico cells b. Micro cells c. Nano cells d. Umbrella cells ans: d In cellular networks, standard base station antennas are replaced by ____________. a. adaptive array b. flat plate antenna c. dipole array d. focused antenna ans: a What is the basis of the first generation wireless local loop? a. Digital cellular technology b. Analogue cellular technology c. PSTN d. AMPS technology ans: b When the calling party hears a "busy" tone on his telephone, the call is considered a. lost b. disconnected

c. completed d. incomplete ans: c Short-circuited stubs are preferred to open circuited because the latter are a. more difficult to make and connect b. made of a transmission line with a different c haracteristic impedance c. liable to radiate d. incapable of giving a full range of re actances ans: c What is the ratio of the reflected voltage to the incident voltage? a. VSWR b. ISWR c. SWR d. Coefficient of reflection ans: d One method of determining antenna impedance. a. Stub matching b. Trial and error c. Smith chart d. Quarter-wave matching ans: d -

___________ is a single conductor running from the transmitter to the antenna. a. Single-wire line b. Microstrip c. Twin-lead d. Coaxial line ans: a Coaxial cable impedance is typically ________________. a. 150 to 300 ohms b. 50 to 75 ohms c. 30 to 45 ohms d. 300 to 600 ohms ans: b Waveguide becomes compulsory above what frequencies? a. Above 3 GHz b. Above 10 kHz c. At 300 MHz d. Above 10 GHz ans: a Nominal voice channel bandwidth is ___________. a. 20 to 30 kHz b. 0 to 3 kHz c. 4 kHz

d. 55 kHz above ans: c Echo suppressors are used on all communications system when the round trip propagation time exceeds _____________. a. 50 ms b. 30 ms c. 100 ms d. 1 ms ans: a A radio transmission line of 300 ohms impedance is to be connected to an antenna having an input impedance of 150 ohms. What is the impedance of a quarter-wave matching line? a. 212 ohms b. 250 ohms c. 200 ohms d. 150 ohms ans: a Quarter-wavelength line is used as ___________. a. impedance transformer b. lecher line c. transmission line d. harmonic suppressor ans: a -

The transmission lines which can convey electromagnetic waves only in higher modes is usually called a. coaxial cable b. waveguide c. power lines d. twisted wire of telephone line ans: b Why is nitrogen gas sometimes used in waveguide? a. To increase the distributed capacitance b. To keep the waveguide dry c. To reduce the skin effect at the walls of the guide d. To raise the guide's wave impedance ans: b Why is it impossible to use a waveguide at low radio frequencies? a. High dielectric loss b. Severe attenuation c. Excessive radiation d. The size of the waveguide ans: d How do you couple in and out of a waveguide? a. Wrap a coil of wire around one end of the waveguide b. Insertion of an E-probe into the w aveguide c. Insertion of an H-loop into the waveguide

d. Both B and C ans: d A rectangular waveguide is operating in the dominant TE(10) mode. The associated flux lines are established a. transversely across the narrow dimension of the waveguide b. transversely across the wide dimension of the waveguide c. in the metal walls parallel to the direction of propagation d. in the metal walls perpendicular to the direction of propagation ans: a For dominant mode of a rectangular waveguide, t he distance between two instantaneous consecutive positions of maximum field intensity (in a direction parallel to the walls of the waveguide) is referred to as half of the a. free-space wavelength b. cutoff wavelength in the wide dimension c. guide wavelength d. group wavelength ans: c The guide wavelength, lambda g, in a re ctangular waveguide is a. equal to the free-space wavelength at the cutoff frequency b. equal to the free-space wavelength for the same signal frequency c. less than the free-space wavelength at the cut-off frequency d. greater than the free-space wavelength at the same signal frequency ans: d -

Using the TE(10) mode, microwave power can only be transmitted in free rectangular guide provided a. the wider dimension is less than one-half of the wavelength in free space b. the narrow dimension is less than one-quarter of the wavelength in free space c. the wide dimension is greater t han one-half of the guide wavelength d. the wide dimension is greater than one-half of the wavelength in free space ans: d If the signal frequency applied to a rectangular guide is increased and the dominant mode is employed a. the free space wavelength, lambda, is increased b. the phase velocity, Vphi, increased c. the guide wavelength is increased d. the group velocity, Vg is incre ased ans: d If a 6 GHz signal is applied to a rectangular waveguide and the reflection angle, theta, is 20 degrees, what is the value of the guide wavelength, lambda g? a. 6.10 cm b. 5.32 cm c. 4.78 cm d. 5.00 cm ans: b The inner dimensions of a rectangular waveguide are 1 .75 cm by 3.5 cm. The cutoff wavelength for the dominant mode is a. 1.75 cm b. 3.5 cm

c. 7.0 cm d. 0.4375 cm ans: c A signal whose wavelength is 3.5 cm is being propagated along a guide whose inner dimensions are 2 cm by 4 cm. What is the value of the guide wavelength, lambda g? a. 3.12 cm b. 3.89 cm c. 3.57 cm d. 6.30 cm ans: b The frequency range over which a rectangular waveguide is excited in the dominant mode is limited to a. the difference between the frequency for which the reflection angle, theta, is 90 degrees and the frequency for which theta is zero. b. the difference between the frequency for which the free-space wavelength is equal to the cutoff value and the frequency for which the free-space wavelength is equal to the guide wavelength c. the difference between the frequency at which the cutoff wavelength is twice the narrow dimension. d. none of these ans: c If a rectangular waveguide is to be excited in the dominant mode, the E -probe should be inserted a. at the sealed end b. at a distance of one quarter-wavelength from the sealed end c. at a distance of one-half wavelength from the sealed end d. at a distance of three-quarters of a wavelength from the sealed end ans: b

A quarter-wave line is connected to an RF generator and is shorted out at the far end. What is the input impedance to the line generator? a. a low value of resistance b. a high value of resistance c. a capacitive resistance which is e qual in the value to the line's surge impedance d. an inductive resistance which is equal to the value to the line's surge impedance ans: b If the SWR on a transmission line has a high value, the reason could be a. an impedance mismatch between the line and the load. b. that the line is nonresonant c. a reflection coefficient of zero at the load d. that the load is matched to the line ans: a If a quarter-wave transmission line is shorted at one e nd a. there is minimum current at the shorted end b. the line behaves as a parallel-tuned circuit in relation to the generator c. the line behaves as a series-tuned circuit in relation to the generator d. there is a minimum voltage at the shorted end. ans: b A 50-ohm transmission line is feeding an antenna which represents a 50 ohms resistive load. To shorten the line, the length must be a. any convenient value

b. an odd multiple of three-quarters of a wavelength c. an odd multiple of half a wavelength d. an even multiple of a quarter of a wavelength ans: a The outer conductor of the coaxial cable is usually grounded a. at the beginning and at the end of the cable b. only at the beginning of the cable and only at the end of the c able c. only at the end of the cable d. at the middle of the cable ans: a A feature of an infinite transmission line is that a. its input impedance at the generator is equal to the line's surge impedance b. its phase velocity is greater than the velocity of light c. no RF current will be drawn from the generator d. the impedance varies at different positions on the line ans: a When the surge impedance of a line is matched to a load, the line will a. transfer maximum current to the load b. transfer maximum voltage to the load c. transfer maximum power to the load d. have a VSWR equal to zero ans: c

A lossless line is terminated by a resistive load which is not equal to the surge impedance. If the value of the reflection coefficient is 0.5, the VSWR is a. 2 b. 3 c. 4 d. 15 ans: b Ratio of the mismatch between the antenna and the transmitter power. a. Standing wave pattern b. Reflection coefficient c. SWR d. Index of refraction ans: c Emission designation for a facsimile a. H3E and A4E b. R3E and A4E c. F4E and J3E d. F3C and A3E ans: d Commonly used telephone wire. a. AWG #19 b. AWG #18

c. AWG #30 d. AWG #33 ans: a What is the distance traveled by a wave in the time of one cycle? a. Frequency b. Hop c. Wavelength d. Crest ans: c The velocity factor is inversely proportional with respect to the _________. a. square of the dielectric constant b. square root of the dielectric constant c. dielectric constant d. square root of refractive index ans: b What circuit connects a balanced line to an unbalanced line? a. Stub b. Hybrid c. Balun d. Directional coupler ans: c -

To connect a coaxial line to a parallel wire line, _________ is used. a. hybrid circuit b. balun c. directional coupler d. quarter-wave transformer matching circuit ans: b What length for which the input power has been halved for a transmission line with an attenuation of 6 dB/km? a. 1.5 km b. 0.5 km c. 63 km d. 2 km ans: b What is the wavelength in the waveguide with 4.5 GHz cut-off frequency exc ited by 6.7 GHz? a. 0.196 m b. 0.336 m c. 0.136 m d. 0.136 cm ans: a A rectangular waveguide has dimensions of 3 cm x 5 cm. What is the dominant mode cut-off frequency? a. 2 GHz b. 3 GHz

c. 2.5 GHz d. 3.5 GHz ans: b __________ are transmission lines which can convey electromagnetic waves only in higher order modes? a. Coaxial cables b. Twisted pairs of telephone wire c. Power cables d. Waveguides ans: d The amount of uncertainly in a system of symbols is also called a. bandwidth b. loss c. entropy d. quantum ans: c The twists in twisted wire pairs a. reduced electromagnetic interference b. occur at a 30-degree angle c. eliminate loading d. were removed due to cost ans: a -

An example of bounded medium is a. coaxial cable b. waveguide c. fiber-optic cable d. all of the above ans: d Loading means to the addition of a. resistors b. capacitors c. bullets d. inductance ans: d What is the most commonly used transmission line for high frequency application? a. Two-wire balance line b. Single wire c. Three-wire line d. Coaxial ans: d The characteristic impedance of a t ransmission does not depend upon its a. length b. conductor diameter c. conductor spacing

d. dielectric material ans: a One of the following is not a common t ransmission line impedance. a. 50 ohms b. 75 ohms c. 120 ohms d. 300 ohms ans: c For maximum absorption of power at the antenna, the relationship between the characteristic impedance of the line Zo and the load impedance Zl should be a. Zo = Zl b. Zo > Zl c. Zo < Zl d. Zo = 0 ans: a The mismatch between antenna and transmission line impedance cannot be corrected for by a. using LC matching network b. adjusting antenna length c. using a balun d. adjusting the length of transmission line ans: d -

____________ is a pattern of voltage and current variations along a transmission line not terminated in its characteristic impedance. a. an electric field b. radio waves c. standing waves d. a magnetic field ans: c Which is the desirable SWR on a transmission line? a. 0 b. 1 c. 2 d. infinity ans: b A 50 ohms coax is connected to a 73-ohms antenna. What is the SWR? a. 0.685 b. 1 c. 1.46 d. 2.92 ans: c What is the most desirable reflection coefficient? a. 0 b. 0.5 c. 1

d. infinity ans: a What is the ratio expressing the percentage of incident voltage reflected on a transmission line? a. Velocity factor b. Standing-wave ratio c. Reflection coefficient d. Line efficiency ans: c The minimum voltage along a transmission line is 260 V, while the maximum is 390 V sub 1. The S WR is a. 0.67 b. 1.0 c. 1.2 d. 1.5 ans: d One meter is one wavelength at a frequency of a. 150 MHz b. 164 MHz c. 300 MHz d. 328 MHz ans: c At very high frequencies. Transmission lines act as

a. tuned circuits b. antennas c. insulators d. resistors ans: b A shorted quarter-wave line at the operating frequency acts like a/an a. capacitor b. inductor c. series resonant circuit d. parallel resonant circuit ans: d A shorted half-wave line at the oper ating frequency acts like a/an a. capacitor b. inductor c. series resonant circuit d. parallel resonant circuit ans: c A medium least susceptible to noise? a. Shielded pair b. Twisted pair c. Fiber-optic d. Coaxial

ans: d A medium most widely used in LANs? a. Parallel-wire line b. Twisted pair c. Fiber-optic d. Coaxial ans: b The most commonly used transmission line in television system. a. Parallel-wire line b. Coaxial cable c. Waveguide d. Open-wire with ceramic supports ans: b The impedance of a TV transmission line depends on several factor s. Which is not one of those factors? a. Diameter b. Length of the wire c. Dielectric material d. Separation between conductors ans: b DC blocks are used in coaxial transmission line for the purpose of a. passing DC while blocking AC

b. passing AC voltage but prevent DC c. preventing AC voltage from re aching the pre-amplifier d. preventing AC power supply voltage from being shorted by a balun or band splitter ans: d _________ is a type of interference caused by off-air TV channels 2 and 4, plus a satellite dish operating on channel 3. a. Adjacent channel interference b. Ghost c. Co-channel interference d. Crosstalk ans: a Dithering (in TVRO communications) is a process for a. reducing the effect of noise on the TVRO video signal b. centering the video fine tuning on TVRO channels c. moving the feedhorn rotor to the precise angle d. moving the actuator exactly onto the desired satellite beam ans: a A network that has an input of 75 dB and an output of 35dB. The loss of the network is ______________. a. -40 dB b. 40 dB c. 40 dBm d. -40 dBm

ans: b Important useful quantities describing waveforms. a. Time and frequency b. Voltage and current c. Frequency and voltage d. Power and frequency ans: c Halving the power means a. 6-dB gain b. 3-dB loss c. 3-dB gain d. 6-dB loss ans: b One neper (Np) is how many decibels? a. 8.866 b. 8.686 c. 8.688 d. 8.868 ans: b A signal is amplified 100 times in power. The dB gain is a. 20 dB

b. 119 dB c. 15 dB d. 25 dB ans: a Which of the following is used to measure S WR? a. Spectrum analyzer b. Reflectometer c. Oscilloscope d. Multimeter ans: b 214-056 twin lead which is commonly used for TV lead-in has a characteristics impedance of a. 52 ohms b. 75 ohms c. 600 ohms d. 300 ohms ans: d What is the characteristic impedance of a transmission line which is to act as a quarterwave m atching transformer between a 175 ohms transmission line and 600 ohms load? a. 300.04 ohms b. 324.04 ohms c. 310.04 ohms d. 320.04 ohms ans: b

What is the EIRP in dBW of a 50 dB antenna connected to transmitter with an output of 10 kW through a transmission line with a loss of 5 dB? a. 85 dBW b. 955 dBW c. 90 dBW d. 80 dBW ans: a A coaxial cable is a good example o f a/an a. unbounded medium b. transmission channel c. non-metallic medium d. bounded medium ans: d If a quarterwave transformer is required to match a 180ohms load to a t ransmission line w/ an impedance of 300ohms, what should be the char. impedance of the matching transformer? Assume that the matching transformer is to be connected directly to the load a. 180 ohms b. 232 ohms c. 300 ohms d. 480 ohms ans: b A transmitter of 100 W RF power output, 100% modulated is operating on a frequency of 169 MHz. The antenna transmission line consists of a 50 ohms coaxial cable 150 ft. long. The coaxial inner conductor

outer diameter is 0.162 in. Determine the outside diameter of the outer conductor if the outer conductor has a thickness of 0.05 in (Assume k = 1). a. 1.0 in b. 0.9 in c. 0.7 in d. 0.5 in ans: d A transmitter of 100 W RF power output, 100% modulated is operating on a frequency of 169 MHz. The antenna transmission line consists of a 50 ohms coaxial cable 150 ft. long. The coaxial inner conductor outer diameter is 0.162 in. The outer conductor has a thickness of 0.05 in (Assume k = 1). In the problem, calculate the line current. a. 1.7 A b. 1.3 A c. 1.5 A d. 1.0 A ans: a A transmitter of 100 W RF power output, 100% modulated is operating on a frequency of 169 MHz. The antenna transmission line consists of a 50 ohms coaxial cable 150 ft. long. The coaxial inner conductor outer diameter is 0.162 in. The outer conductor has a thickness of 0.05 in (Assume k = 1). Determine the total attenuation of the line in the problem. a. 2.0 dB b. 1.5 dB c. 2.5 dB d. 1.0 dB ans: b -

What is the max. subscriber loop length, in ft., of a telephone system if the signaling resistance is 1800 ohms using a tel. cable pair of gauge # 26 with a loop resistance of 83.5 ohms per 1000 ft. Assume the telephone set resistance is equal to 200 ohms. a. 15,161.7 feet b. 19,161 feet c. 15,300 feet d. 20,000 feet ans: b If the same subscriber loop above limits the vo ice attenuation to a maximum of 6 dB, w hat is the maximum allowable subscriber loop length, in feet, using the same gauge # 26 telephone wire? Assume a 2.7 dB loss per mile. a. 20,000 ft b. 13,900 ft c. 15,280 ft d. 11,733 ft ans: d The input is 0.1 W and the net work gain is 13 dB, the output is a. 2.0 W b. 2.5 W c. 1.5 W d. 1.8 W ans: a Known as one-tenth of a neper. a. dB

b. dBm c. dBp d. dNp ans: d The input impedance of a quarterwave short-circuited tr ansmission line at its resonant frequency is a. 0 ohms b. infinite or an open circuit c. ohms d. 70 ohms ans: b The ratio of the largest rms value to the smallest rms value of t he voltage in the line is called a. SWR b. ISWR c. VSWR d. Coefficient of reflection ans: c An open-wire, two-wire transmission line is to be c onnected to a dipole antenna through a quarterwave matching stub. At a frequency of 1 0 MHz, compute the length of t he dipole a. 20 m b. 7.5 m c. 15 m d. 25 m ans: c

An open-wire, two-wire transmission line is to be c onnected to a dipole antenna through a quarte rwave matching stub. At a frequency of 1 0 MHz, compute the length of t he quarterwave stub. a. 15 m b. 7.5 m c. 20 m d. 25 m ans: b To find the char. Impedance of a coaxial cable, measurements are made with (a) the far end open circuited & (b) far end short circ uited, the corresponding readings being a) Ro=3ohms & Xc=55ohms, capacitive b) Rs=10ohms & Xl=90ohms, inductive What is the characteristic impedance, Zo, of the line? a. 75.7 - j2.0 ohms b. 70.7 + j1.19 ohms c. 87.5 - j5 ohms d. 70.7 - j1.97 ohms ans: d A TV antenna receives a signal measured at 200 µV and is immediately amplified by a pre -amplifier with a 15 dB gain. This amplified signal then passes through a coaxial cable with 3 dB loss, what is the resulting input to the TV set, in dBmV? a. 1.98 b. 13.98 c. -1.98 d. -13.98 ans: c -

The characteristic impedance of a transmission line does not depend upon its __________. a. conductor spacing b. conductor diameter c. length d. conductor radius ans: c What does a power difference of -3 dB mean? a. a loss of one third of the power b. a loss of one half of the power c. a loss of three watts of the power d. no significant change ans: b Which of the following is an advantage of the balance transmission line? a. Easy installation b. Outer shield eliminates radiation losses c. Low attenuation d. None of these ans: c Waveguides are used mainly for microwave transmission because a. they are bulky at lower frequencies b. losses are heavy at lower frequencies c. they depend on straight line propagation

d. no generators are powerful enough to excite them ans: d The input is 1 W and the network loss is 27 dB, the output is a. 1 mW b. 3 mW c. 2 mW d. 4 mW ans: c A combiner has two inputs + 30 dBm and + 30 dBm, what is the resultant output? a. + 36 dBm b. + 30 dBm c. + 60 dBm d. + 33 dBm ans: d The ratio of the smallest to the largest rms current value is called a. SWR b. VSWR c. ISWR d. Coefficient of reflection ans: c If the ratio of the maximum current to the minimum current in a transmission line is 2:1 then the ratio of maximum voltage to minimum voltage is

a. 4:1 b. 1:2 c. 1:4 d. 2:1 ans: d Two wires of 600 ohms characteristic impedance is to be constructed out of a number 12 wire (81 mils). Find the attenuation of the line at 0.6 G Hz per 100 feet length. a. 0.05 dB b. 0.55 dB c. 0.44 dB d. 0.35 dB ans: c Two wires of 600 ohms characteristic impedance is to be constructed out of a number 12 wire (81 mils). Determine the spacing between wires from center to center. a. 6 in b. 4 in c. 5 in d. 3 in ans: a A lossless transmission line has a shunt capacitance of 100 nF/m and a series inductance of 4 mH/m. What is the characteristic impedance? a. 500 ohms b. 400 ohms c. 300 ohms

d. 200 ohms ans: d A ten times power change in transmission system is equivalent to a. 10 dBm b. 10 dB c. 20 dB d. 100 dB ans: b A type of transmission line employed where balanced properties are required. a. Balun b. Parallel-wire line c. Coaxial line d. Quarterwave line ans: b What is the characteristic impedance o f a transmission line which has a capacitance of 40 nF/ft and an inductance of 0.5 mH/ft a. 111.8 ohms b. 110.8 ohms c. 112.8 ohms d. 109.8 ohms ans: a -

The input power to a loss-free cable is 5W. If the reflected power is 7 dB down on the incident power, the output power to the load is a. 4 W b. 5 W c. 6 W d. 7 W ans: a To be properly matched the ratio o f a maximum voltage along a transmission line should be equal to a. 1 b. 10 c. 50 d. 2 ans: a A coaxial line with an outer diameter of 6 mm has a 50 ohms characteristic impedance. If the dielectric constant of the insulation is 1.60, calculate the inner diameter. a. 2.09 cm b. 2.09 in c. 2.09 mm d. 2.09 mm ans: c If an amplifier has equal input and output impedances, what voltage rat io does the gain of 50 dB represent? a. 316.2 b. 325.2

c. 320.1 d. 315.0 ans: a What is the inductance per foot of a cable that has a capacitance of 50 pF/ft and a characteristic impedance of 60 ohms? a. 0.167 µH/ft b. 0.178 µH/ft c. 0.19 µH/ft d. 0.18 µH/ft ans: d The ratio between the energy absorbed by a surface to the total energy received by the surface. a. Reflection coefficient b. Absorption coefficient c. Linear coefficient d. Thermal coefficient ans: b When the diameter of the conductors of a 2 wire transmission line is held constant, the effect of decreasing the distance between the conductors is a. increase the surge impedance b. increase the radiation resistance c. decrease the SWR d. decrease the impedance ans: d

The higher the gauge number of a conductor a. the bigger the diameter b. the higher the resistance or the smaller the diameter c. the higher the resistance d. none of these ans: b A short length of transmission line used to reduce/eliminate standing waves in the main transmission line. a. Stub b. Balun c. lambda/4 transformer d. Slot ans: c Ratio of reflected power to incident power? a. Incidence b. Reflectance c. Reflection index d. None of these ans: b A quarter wave transformer is used to match a 600 ohms load ante nna to a line of 52 ohms impedance, the characteristic impedance of the m atching transformer is a. 200 ohms

b. 150 ohms c. 176 ohms d. 300 ohms ans: d What is the capacitance of 55 miles # 44 copper wire spaced 18 inches? From wire tables, # 44 wire has a radius to 0.10215 in. a. 0.476 µF b. 0.476 nF c. 0.476 pF d. 0.476 fF ans: a A two-wire transmission line consists of No. 12 wire AWG (81 mils). The distance between wire ce nters is 10 inches. What is the characteristic impedance of the line? a. 650 ohms b. 300 ohms c. 600 ohms d. 660 ohms ans: d A two-wire transmission line consists of No. 12 wire AWG (81 mils). The distance between wire c enters is 10 inches. What is the attenuation in dB per 100 ft. of t he line for a frequency of 4 MHz? a. 0.05 b. 0.03 c. 0.04 d. 0.06

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