RAWS CDC Set B UREs Vol. 1-3 Combined

What scientific notation is the correct way to express the number 764,500?

7.645 x 10^5

What metric prefix is used to describe the decimal number .001?

Milli

An atom becomes an ion by

gaining or losing electrons in it outer shell.

Which electrical term is measured in watts (W)?

Power

With the alternating current (AC) method, voltage forces electrons to flow

first in one direction, then in the opposite direction, alternating very quickly.

In 1819, Hans Christian Oersted discovered the strength of a magnetic field can be changed by varying what characteristic?

Current through a conductor.

If a conductor lies in a magnetic field, and either the field or conductor moves, a voltage is induced in the conductor. This effect is called

electromagnetic induction

A resistor is used in a circuit to

control current flow.

A capacitor will oppose a change in

voltage and store energy in an electrostatic field.

The two basic purposes of a transistor are either to perform as a

switch or amplify a circuit.

In a schematic diagram, how is current flow always portrayed on a transistor when it is forward biased

Against the arrow.

A Zener diode is specifically designed to operate in

reverse bias mode.

An advantage of integrated circuits (IC) is that they

are more reliable.

The number of pulses in the direct current (DC) output of a bridge rectifier is called the

ripple frequency.

What power supply circuit senses changes in output voltages and compensates for the changes, usually within plus or minus (±) 0.1 percent?

Regulator

What wave-shaping circuit ties down the upper or lower extremity of a waveform to a fixed direct current (DC) potential?

Clamping

What is the binary equivalent of the decimal number 7?

111

What is the binary coded decimal (BCD) equivalent of the binary number 1011?

0001 0001

Which is not a conventional problem that microwave tubes overcome in order to be used in high power, high frequency oscillators and amplifiers?

Inter-cathode resistance

What is the wavelength if the frequency is changed from 150 megahertz (MHz) to 250 MHz?

1.2 meters

On a transmission line with an open termination, the wave is reflected back to the source and

there would be significant signal loss

What data bus was originally developed for military avionics applications?

Military Standard (MIL-STD)-155

Energy travels through a waveguide because of

interaction of magnetic and electric fields.

Three devices used to inject or remove energy from waveguides are known as

probes, loops, and slots.

When the modulating signal and carrier signal are combined within a modulator, the output signal contains the

carrier, upper sideband, and lower sideband.

If the modulating audio signal is 10 kilohertz (kHz) wide, what is the bandwidth (BW) of the transmitted amplitude modulated signal?

20 kHz

Reducing modulation to less than 100 percent results in

no reduction in carrier power.

The oscillator output in a frequency modulation (FM) modulator increases in frequency with each

positive half cycle of the modulating signal.

The formula to find the modulating index is

deviation divided by frequency of modulation.

What is the modulation index of a 5 kilohertz (kHz) modulating signal that has enough peak voltage to cause a deviation of 15 kHz?

3.0.

In phase modulation, the rate of phase shift is

proportional to the frequency of the modulating signal.

Space modulation is commonly referred to as

difference in the depth of modulation (DDM).

What is the first step in the pulse code modulation (PCM) process?

Band-limiting the analog signal

How does synchronous transmission reduce the overhead costs of data transmission?

Blocks many characters together for transmission.

Which method of transmission requires the receiving end to be synchronized with the transmitting commutator?

Time division multiplexing.

When using forward error control as a method of error correction, error correction takes place

at the receiving end.

Which statement describes an advantage of using fiber optic (FO) cables?

Electromagnetic fields do not affect fiber optic cables.

One disadvantage to using fiber optic (FO) cables is that

nuclear radiation can darken the optical fiber and cause signal loss.

What component of a fiber optic (FO) cable provides the reflective surface that allows light to propagate?

Cladding.

When considering light wave propagation, what is the name of the angle between the normal in the first material and the ray that is bounced back in the first material?

Angle of reflection.

What logarithmic expression do we use to specify the ratio of power loss in fiber optic (FO) cables?

Decibels-per-kilometer (dB/km).

What is the most useful way to classify fiber optic (FO) cable?

Core's refractive index profile and number of modes.

What type of fiber has a core diameter of 50-125 micrometers (µm) and consists of numerous concentric layers of glass, something like the annular rings of a tree, configured to reduce dispersion?

Multimode graded-index.

What is the process of heterodyning an intelligence (audio) signal with a radio frequency (RF) carrier to produce a new signal?

Amplitude modulation (AM).

The frequency range of the AN/GRT−22 transmitter, in megahertz (MHz), is

225.000 to 399.975

In what AN/GRT−21/22 transmitter transmit mode should you connect the antenna to K1J3?

10-watt (W).

What AN/GRT−21/22 transmitter component eliminates unwanted harmonics generated in the A10 driver?

Tunable filter, FL2.

If the AN/GRT−21/22 transmitter power supply temperature is too high, the thermal detector in the A7 module

develops the keyer inhibit voltage.

What type of multiplier does the AN/GRT−21 transmitter have?

Doubler

What should you do if an AN/GRT−21/22 transmitter's voltage standing wave ratio (VSWR) exceeds 3:1?

Bypass the linear power amplifier (LPA)

What is the difference in channel spacing between the very high frequency (VHF) CM- 300/350 and the ultra high frequency (UHF) CM-300 transmitters?

VHF has a channel spacing of 8.33 or 25 kHz and the UHF channel spacing is 25 kHz only

The radio frequency (RF) power output of the CM-350 transmitter is

12 to 35 watts (W)

What term describes the process of tuned circuits selecting a band of receiver frequencies around a desired signal?

Pre-selection.

Which receiver component determines the overall selectivity?

Intermediate frequency (IF) filter

The image frequency is a(n)

undesired signal that, when mixed in the mixer, produces the correct IF.

Diode detectors give

high-fidelity detection for signals of sufficient amplitude

The automatic gain control (AGC) voltage maintains a constant audio output with a

varying RF input.

Which circuit cuts off a receiver's audio output if the radio frequency (RF) signal is too weak and allows the signal to reproduce when the RF signal strength meets or exceeds a predetermined level?

Squelch.

CM-300 series receivers support legacy analog audio and

Voice over Internet Protocol (VoIP)

Both CM-300 series receivers can operate on

120 V AC or 24 V DC

How many seconds maximum does it take the AN/GRC-171/211 transceiver to tune?

10

What is the transmit duty cycle for the AN/GRC-171 transceiver?

9 minutes transmit, 1 minute receive

No matter the input keying voltage to the AN/GRC-171/211 transceiver, the output is always

a ground

In the audio section of the AN/GRC-171/211 transceiver, what component keeps the modulation percentage constant?

Compression amplifier

What happens to the audio in the AN/GRC-171/211 transceiver when the squelch sample is greater than the front panel squelch reference?

Audio is heard at the speaker.

When a CM-300 series transmitter and receiver are connected to a common antenna, and the antenna transfer relay (ATR) switch position is set to ATR0, the transmit and receive switching is handled by

an internal ATR switch in the transmitter.

What needs to happen in the CM-350 transceiver configuration antenna transfer relay (ATR) switch in order to transmit?

The transmitter keys, then the ATR routes the transmit signal to the antenna.

The biggest limitation to space-wave communications is

curvature of the Earth

A theoretically perfect radiator (antenna) that radiates equally well in all directions is

isotropic.

What type of antenna receives well in all directions but also allows interference from all directions

Omnidirectional

How many channels does the CU-547/GR antenna coupler support

4

What type of line fault can be found by putting a tone on one end and checking for continuity at the distant end

Open circuit.

When using the Fluke 8025A multimeter, what is the input direct current (DC) voltage range that can be measured when the function selector is in the DC volts (V) position?

-1000 to +1000

When using the Fluke 8025A multimeter for diode checks, what does it mean when you get an "OL" indication when you place the leads across the diode and also when the leads are reversed?

Diode is considered non-operational.

What oscilloscope control adjusts how fast the trace is drawn across the screen?

Time per division (TIM/DIV)

Which is not a reason why oscilloscope probes are used?

They ensure circuit loading.

Before measuring a signal with the oscilloscope and the source voltage is totally unknown, it is wise to start with a divider probe rated at

100:1

Which test equipment item would you use to check transmission lines and antenna systems for proper operation?

Radio frequency (RF) generator.

Which is not a waveform produced by a function generator?

Compound wave

The decibel (dB) does not (in itself) indicate power; instead, it indicates a ratio or comparison between

two power levels.

What feature of the 436A power meter is ideal for monitoring fast changes while adjusting peak transmitter output?

Auxiliary meter.

For greatest wattmeter accuracy, select the power element(s) having

the lowest possible power range that will not result in over-ranging.

When bench-checking a transmitter, what test equipment should you use to absorb any transmitted radio frequency (RF) signals?

Dummy load

What test equipment enables technicians to communicate with telephone switching equipment through the use of pulse, dual tone multi-frequency (DTMF), and multi-frequency (MF) dialing?

Ameritec Model (AM)‒48 transmission test set.

When testing a fiber optic (FO) cable, what is the energy that travels back toward the optical source called?

Backscatter.

When measuring high noise figures with a noise figure meter, at what decibel (dB) level does the result become very inaccurate?

10

The tone generator applies an audio tone to a pair or cable and the inductive amplifier is used to

listen for the generated tone at the other end.

What test equipment is essentially an upgraded, portable spectrum analyzer?

Field Fox.

On the vector voltmeter, the phase indicated on the meter represents the relative phase between what two signals?

B channel with respect to the A channel.

What Precision Approach Radar (PAR) test set allows you to test radar power, frequency, pulse repetition frequency (PRF), range tracking capabilities, receiver bandwidth, and minimum discernible signal?

AN/UPM-145.

How many different pieces of test equipment does a communication service monitor (CSM) have combined in one package?

16.

What test equipment allows individual access to all signal conductors in a 25-wire Recommended Standard (RS)-232 connector?

Breakout box.

Which is not an acceptable action to take if a communications facility ground testing reveals more than 10 ohms (Ω) resistance?

Watering the soil around the facility

When an aircraft, vehicle, or person enters the protected area of a surface designated for the landing and take-off of aircraft without approval from Air Traffic Control Tower (ATCT), it is called a

runway incursion.

When selecting a site for the Instrument Landing System (ILS), what is the localizer maximum height tolerance, in feet, for surface roughness in area "A"?

±0.5.

Because of screening, you need to avoid placing the AN/TPS−75 Radar System in

depressions and valleys.

When siting weather equipment, when are midfield sensor groups necessary?

Runway is longer than 8,000 feet (ft.) or the location must meet Category II criteria.

A non-rechargeable, primary battery is often referred to as a(n)

dry cell.

Which is not a type of rechargeable, secondary cell battery?

Carbon Zinc.

Which is not an uninterruptible power supply (UPS) topology?

Passive conversion.