FCC Element 3

3-50F4 What is cross-modulation interference?

Modulation from an unwanted signal heard in addition to the desired signal.

3-95P5 What is the main function of the COSPAS-SARSAT satellite system?

Monitor 406 MHz for distress calls from EPIRBs.

3-26C3 An emitter-follower amplifier has:

More current gain than common emitter or common base.

3-52G5 The class AB amplifier output is present for what portion of the input cycle?

More than 180 but less than 360 degrees.

3-26C1 A common base amplifier has:

More voltage gain than common emitter or common collector.

3-79L1 When soldering or working with CMOS electronics products or equipment, a wrist strap:

Must have less than 100,000 ohms of resistance to prevent static electricity.

3-5A4 What are the two basic types of junction field-effect transistors?

N-channel and P-channel.

3-89N1 What data language is bi-directional, multi-transmitter, multi-receiver network?

NMEA 2000.

3-92O5 What pulse width and repetition rate should you use at short ranges?

Narrow pulse width and fast repetition rates.

3-32D3 What will occur if an amplifier input signal coupling capacitor fails open?

No amplification will occur, with DC within the circuit measuring normal.

3-100Q5 Do shorted-stub lightning protectors work at all frequencies?

No, only at the tuned frequency band.

3-100Q3 Should you use a power drill without eye protection?

No.

3-71K2 What is meant by the term "night effect" when using an aircraft's Automatic Direction Finding (ADF) equipment? Night effect refers to the fact that:

Non Directional Beacon (NDB) transmissions can bounce-off the Earth's ionosphere at night and be received at almost any direction.

3-87N5 Which of the following statements concerning satellite EPIRBs is true?

Once activated, these EPIRBs transmit a signal for use in identifying the vessel and for determining the position of the beacon.

3-13B3 746 watts, corresponding to the lifting of 550 pounds at the rate of one-foot-per-second, is the equivalent of how much horsepower?

One horsepower.

3-29D3 How could voltage be greater across reactances in series than the applied voltage?

Resonance.

3-8A1 What is the term used to identify an AC voltage that would cause the same heating in a resistor as a corresponding value of DC voltage?

Root mean square (RMS).

3-75L5 Which of the following frequency standards is used as a time base standard by field technicians?

Rubidium Standard.

3-90O4 Shipboard RADAR is most commonly operated in what band?

SHF.

3-75L6 Which of the following contains a multirange AF voltmeter calibrated in dB and a sharp, internal 1000 Hz bandstop filter, both used in conjunction with each other to perform quieting tests?

SINAD meter.

3-58H1 In Figure 3H17, the block labeled 4 would indicate that this schematic is most likely a/an:

SSB radio transmitter.

3-45F3 A receiver selectivity of 2.4 kHz in the IF circuitry is optimum for what type of signals?

SSB voice.

3-97P2 The INMARSAT mini-M system is a:

Satellite system utilizing spot beams to provide for small craft communications.

3-7A5 What type of wave is made up of sine waves at the fundamental frequency and all the harmonics?

Sawtooth wave.

3-7A6 What type of wave is characterized by a rise time significantly faster than the fall time (or vice versa)?

Sawtooth wave.

3-46F3 What is the primary purpose of the first IF amplifier stage in a receiver?

Selectivity.

3-82M4 A TDMA radio uses what to carry the multiple conversations sequentially?

Separate time slots.

3-27C6 What circuit component must be connected in series to protect an LED?

Series resistor.

3-77L6 What instrument is commonly used by radio service technicians to monitor frequency, modulation, check receiver sensitivity, distortion, and to generate audio tones?

Service monitor.

3-7A4 What is the description of a square wave?

. A wave that abruptly changes back and forth between two voltage levels and stays at these levels for equal amounts of time.

3-7A1 What is a sine wave?

. A wave whose amplitude at any given instant can be represented by the projection of a point on a wheel rotating at a uniform speed.

3-1A4 What device is used to store electrical energy in an electrostatic field?

. Capacitor.

3-14B4 What is the meaning of the term "time constant of an RL circuit"? The time required for the:

. Current in the circuit to build up to 63.2% of the maximum value.

3-55G1 What will occur when a non-linear amplifier is used with a single-sideband phone transmitter?

. Distortion.

3-8A3 Halving the cross-sectional area of a conductor will:

. Double the resistance.

3-6A1 An AC ammeter indicates:

. Effective (RMS) values of current.

3-38E3 What does the term "IO" mean within a microprocessor system?

. Input-output.

3-48F1 What is a product detector?

. It uses a mixing process with a locally generated carrier.

3-21C2 A transformer used to step up its input voltage must have:

. More turns of wire on its secondary than on its primary.

3-5A5 A common emitter amplifier has:

. More voltage gain than a common collector.

3-8A5 How do you compute true power (power dissipated in the circuit) in a circuit where AC voltage and current are out of phase?

. Multiply apparent power times the power factor.

3-68K3 The Distance Measuring Equipment (DME) ground station has a built-in delay between reception of an interrogation and transmission of the reply to allow:

. Operation at close range.

3-6A4 What is the easiest voltage amplitude to measure by viewing a pure sine wave signal on an oscilloscope?

. Peak-to-peak.

3-8A4 Which of the following groups is correct for listing common materials in order of descending conductivity?

. Silver, copper, aluminum, iron, and lead.

3-7A3 What type of wave is made up of sine waves of the fundamental frequency and all the odd harmonics?

. Square.

3-8A6 Assuming a power source to have a fixed value of internal resistance, maximum power will be transferred to the load when:

. The load impedance equals the internal impedance of the source.

3-90O3 What is the normal range of pulse widths?

.05 s to 1.0 s.

3-66J5 Referred to the fundamental frequency, a shorted stub line attached to the transmission line to absorb even harmonics could have a wavelength of:

1/4 wavelength.

3-9B3 If a current of 2 amperes flows through a 50-ohm resistor, what is the voltage across the resistor?

100 volts.

3-55G5 What is the output peak envelope power from a transmitter as measured on an oscilloscope showing 200 volts peak-to-peak across a 50-ohm load resistor?

100 watts.

3-67J4 What is the effective radiated power of a repeater with 100 watts transmitter power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 7 dB antenna gain?

100 watts.

3-73K3 Typical airborne HF transmitters usually provide a nominal RF power output to the antenna of ____ watts, compared with ____ watts RF output from a typical VHF transmitter.

100, 20

3-99Q4 At what aggregate power level is an MPE (Maximum Permissible Exposure) study required?

1000 Watts ERP.

3-52G4 What is the approximate DC input power to a Class AB RF power amplifier stage in an unmodulated carrier transmitter when the PEP output power is 500 watts?

1000 watts.

3-72K1 What type of antenna pattern is radiated from a ground station phased-array directional antenna when transmitting the PPM pulses in a Mode S interrogation signal of an aircraft's Traffic alert and Collision Avoidance System (TCAS) installation?

1030 MHz directional pattern.

3-69K3 What is the frequency range of the ground-based Very-high-frequency Omnidirectional Range (VOR) stations used for aircraft navigation?

108.00 MHz to 117.95 MHz.

3-70K1 What is the frequency range of the localizer beam system used by aircraft to find the centerline of a runway during an Instrument Landing System (ILS) approach to an airport?

108.10 MHz to 111.95 MHz.

3-76L1 What is used to decrease circuit loading when using an oscilloscope?

10:1 divider probe.

3-6A3 What is the RMS voltage at a common household electrical power outlet?

117-V AC.

3-72K3 What is the frequency range of an aircraft's Very High Frequency (VHF) communications?

118.000 MHz to 136.975 MHz (worldwide up to 151.975 MHz).

3-98P1 Global Positioning Service (GPS) satellite orbiting altitude is:

12,554 miles.

3-90O2 The RADAR range in nautical miles to an object can be found by measuring the elapsed time during a RADAR pulse and dividing this quantity by:

12.346 μs.

3-88N2 What is the standard scan rate for high-frequency 3 MHz - 23 MHz weather facsimile reception from shore stations?

120 lines per minute.

3-12B5 What is the RMS value of a 340-volt peak-to-peak pure sine wave?

120 volts AC.

3-72K4 Aircraft Emergency Locator Transmitters (ELT) operate on what frequencies?

121.5, 243 and 406 MHz.

3-98P2 The GPS transmitted frequencies are:

1227.6 MHz and 1575.4 MHz.

3-67J5 What is the effective radiated power of a repeater with 100 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain?

126 watts.

3-44F1 What is the image frequency if the normal channel is 151.000 MHz, the IF is operating at 11.000 MHz, and the LO is at 140.000 MHz?

129.000 MHz.

3-14B6 After two time constants, the capacitor in an RC circuit is discharged to what percentage of the starting voltage?

13.5 %

3-17B2 In polar coordinates, what is the impedance of a network composed of a 100-ohm-reactance inductor in series with a 100-ohm resistor?

141 ohms, /45 degrees

3-45F1 What degree of selectivity is desirable in the IF circuitry of a wideband FM phone receiver?

15 kHz.

3-60I4 What is the total voltage when 12 Nickel-Cadmium batteries are connected in series?

15 volts.

3-67J2 What is the effective radiated power of a repeater with 75 watts transmitter power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 10 dB antenna gain?

150 watts.

3-11B4 What is the most the actual transmitter frequency could differ from a reading of 156,520,000 hertz on a frequency counter with a time base accuracy of ± 1.0 ppm?

156.52 Hz.

3-11B5 What is the most the actual transmitter frequency could differ from a reading of 156,520,000 Hertz on a frequency counter with a time base accuracy of +/- 10 ppm?

1565.20 Hz.

3-16B5 In rectangular coordinates, what is the impedance of a network composed of a 0.01-microfarad capacitor in parallel with a 300-ohm resistor, at 50 kHz?

159 - j150

3-53G3 What is the total bandwidth of a FM phone transmission having a 5 kHz deviation and a 3 kHz modulating frequency?

16 kHz.

3-95P2 What frequency band is used by the Iridium system for telephone and messaging?

1616 -1626 MHz.

3-61I6 A 12.6 volt, 8 ampere-hour battery is supplying power to a receiver that uses 50 watts and a RADAR system that uses 300 watts. How long will the battery last?

17 minutes or 0.3 hours.

3-60I3 What capacity in amperes does a storage battery need to be in order to operate a 50 watt transmitter for 6 hours? Assume a continuous transmitter load of 70% of the key-locked demand of 40 A, and an emergency light load of 1.5 A.

177 ampere-hours.

3-18B1 What is the magnitude of the impedance of a series AC circuit having a resistance of 6 ohms, an inductive reactance of 17 ohms, and zero capacitive reactance?

18 ohms.

3-52G1 The class B amplifier output is present for what portion of the input cycle?

180 degrees.

3-71K1 What is the frequency range of an aircraft's Automatic Direction Finding (ADF) equipment?

190 kHz to 1750 kHz.

3-60I2 A battery with a terminal voltage of 12.5 volts is to be trickle-charged at a 0.5 A rate. What resistance should be connected in series with the battery to charge it from a 110-V DC line?

195 ohms.

3-64J3 Which of the following represents the best standing wave ratio (SWR)?

1:1.

3-20C3 In Figure 3C4, which component (labeled 1 through 4) is used to provide a signal ground?

2

3-32D6 With a pure AC signal input to the circuit shown in Figure 3D11, what output wave form would you expect to see on an oscilloscope display?

2

3-36E1 A flip-flop circuit is a binary logic element with how many stable states?

2

3-36E2 What is a flip-flop circuit? A binary sequential logic element with ___stable states.

2

3-36E3 How many flip-flops are required to divide a signal frequency by 4?

2

3-43F6 In Figure 3F15, which block diagram symbol (labeled 1 through 4) is used to represent a local oscillator?

2

3-58H2 In Figure 3H17, which block diagram symbol (labeled 1 through 4) represents where audio intelligence is inserted?

2

3-32D2 Which lamps would be lit in the circuit shown in Figure 3D8?

2, 3, 4, 7 and 8.

3-33E2 What is the voltage range considered to be a valid logic high input in a TTL device operating at 5.0 volts?

2.0 to 5.5 volts.

3-60I5 The average fully-charged voltage of a lead-acid storage cell is:

2.06 volts.

3-47F1 A good crystal band-pass filter for a single-sideband phone would be?

2.1 KHz.

3-57H3 What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz and accepting a maximum modulation rate of 3.5 kHz?

2.14

3-22C6 What is the range of voltage ratings available in Zener diodes?

2.4 volts to 200 volts and above.

3-55G4 What is the approximate ratio of peak envelope power to average power during normal voice modulation peak in a single-sideband phone signal?

2.5 to 1.

3-18B3 Given a power supply with a no load voltage of 12 volts and a full load voltage of 10 volts, what is the percentage of voltage regulation?

20 %

3-16B1 What is the impedance of a network composed of a 0.1-microhenry inductor in series with a 20-ohm resistor, at 30 MHz? Specify your answer in rectangular coordinates.

20 +j19

3-27C4 What would be the maximum current to safely illuminate a LED?

20 mA.

3-27C3 What is the approximate operating current of a light-emitting diode?

20 mA.4

3-18B2 A 1-watt, 10-volt Zener diode with the following characteristics: Imin. = 5 mA; Imax. = 95 mA; and Z = 8 ohms, is to be used as part of a voltage regulator in a 20-V power supply. Approximately what size current-limiting resistor would be used to set its bias to the midpoint of its operating range?

200 ohms.

3-10B1 What is the peak-to-peak RF voltage on the 50 ohm output of a 100 watt transmitter?

200 volts.

3-96P1 What is the orbital altitude of INMARSAT Satellites?

22,177 miles.

3-15B1 What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors all in parallel?

220 seconds.

3-15B4 What is the time constant of a circuit having a 220-microfarad capacitor and a 1-megohm resistor in parallel?

220 seconds.

3-15B6 What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors all in series?

220 seconds.

3-98P3 How many GPS satellites are normally in operation?

24

3-17B5 In polar coordinates, what is the impedance of a network comprised of a 400-ohm-reactance inductor in parallel with a 300-ohm resistor?

240 ohms, /36.9 degrees

3-17B1 What is the impedance of a network composed of a 100-picofarad capacitor in parallel with a 4000-ohm resistor, at 500 KHz? Specify your answer in polar coordinates.

2490 ohms, /-51.5 degrees

3-85N1 What is the channel spacing used for VHF marine radio?

25 kHz.

3-64J6 There is an improper impedance match between a 30 watt transmitter and the antenna, with 5 watts reflected. How much power is actually radiated?

25 watts.

3-18B5 Given a power supply with a full load voltage of 200 volts and a regulation of 25%, what is the no load voltage?

250 volts.

3-62I5 A 3 horsepower, 100 V DC motor is 85% efficient when developing its rated output. What is the current?

26.300 amps.

3-21C3 A transformer primary of 2250 turns connected to 120 VAC will develop what voltage across a 500-turn secondary?

26.7 volts.

3-21C4 What is the ratio of the output frequency to the input frequency of a single-phase full-wave rectifier?

2:1.

3-20C4 In Figure 3C5, which capacitor (labeled 1 through 4) is being used as a bypass capacitor?

3

3-32D5 In Figure 3D10 with a square wave input what would be the output?

3

3-53G1 What is the modulation index in an FM phone signal having a maximum frequency deviation of 3,000 Hz on either side of the carrier frequency when the modulating frequency is 1,000 Hz?

3

3-53G2 What is the modulation index of a FM phone transmitter producing a maximum carrier deviation of 6 kHz when modulated with a 2 kHz modulating frequency?

3

3-69K2 The rate that the transmitted VOR variable signal rotates is equivalent to how many revolutions per second?

30

3-16B2 In rectangular coordinates, what is the impedance of a network composed of a 0.1-microhenry inductor in series with a 30-ohm resistor, at 5 MHz?

30 +j3

3-64J5 An antenna radiates a primary signal of 500 watts output. If there is a 2nd harmonic output of 0.5 watt, what attenuation of the 2nd harmonic has occurred?

30 dB.

3-67J6 What is the effective radiated power of a repeater with 50 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 7 dB antenna gain?

31.5 watts.

3-10B3 A 500-ohm, 2-watt resistor and a 1500-ohm, 1-watt resistor are connected in parallel. What is the maximum voltage that can be applied across the parallel circuit without exceeding wattage ratings?

31.6 volts.

3-18B4 What turns ratio does a transformer need in order to match a source impedance of 500 ohms to a load of 10 ohms?

7.1 to 1.

3-11B2 The second harmonic of a 380 kHz frequency is:

760 kHz.

3-36E5 How many R-S flip-flops would be required to construct an 8 bit storage register?

8

3-11B3 What is the second harmonic of SSB frequency 4146 kHz?

8292 kHz.

3-14B5 After two time constants, the capacitor in an RC circuit is charged to what percentage of the supply voltage?

86.5 %

3-87N3 In which frequency band does a search and rescue transponder operate?

9 GHz

3-10B5 In Figure 3B2, what is the voltage drop across R1?

9 volts.

3-68K1 What is the frequency range of the Distance Measuring Equipment (DME) used to indicate an aircraft's slant range distance to a selected ground-based navigation station?

962 MHz to 1213 MHz.

3-84M3 Which statement best describes the code used for GMDSS-DSC transmissions?

A 10 bit error correcting code starting with bits of data followed by a 3 bit error correcting code.

3-50F1 Where would you normally find a low-pass filter in a radio receiver?

A and C, but not B.

3-72K2 What type of antenna is used in an aircraft's Instrument Landing System (ILS) marker beacon installation?

A balanced loop reception antenna.

3-48F4 What is a frequency discriminator in a radio receiver?

A circuit for detecting FM signals.

3-37E2 What is an astable multivibrator?

A circuit that alternates between two unstable states.

3-37E3 What is a monostable multivibrator?

A circuit that can be switched momentarily to the opposite binary state and then returns after a set time to its original state.

3-83M1 What is a CODEC?

A coder/decoder IC or circuitry that converts a voice signal into a predetermined digital format for encrypted transmission.

3-2A2 What will produce a magnetic field?

A current flowing through a conductor.

3-63J1 Which of the following could cause a high standing wave ratio on a transmission line?

A detuned antenna coupler.

3-75L2 What is a frequency standard?

A device used to produce a highly accurate reference frequency.

3-31D1 What frequency synthesizer circuit uses a phase comparator, look-up table, digital-to-analog converter, and a low-pass antialias filter?

A direct digital synthesizer.

3-47F4 What is an m-derived filter?

A filter that uses a trap to attenuate undesired frequencies too near cutoff for a constant-k filter.

3-70K4 What type of antenna is used in an aircraft's Instrument Landing System (ILS) glideslope installation?

A folded dipole reception antenna.

3-33E4 TTL inputs left open develop what logic state?

A high-logic state.

3-35E3 For the logic input levels given in Figure 3E13, what are the logic levels of test points A, B and C in this circuit? (Assume positive logic.)

A is high, B is high and C is high.

3-35E2 For the logic input levels shown in Figure 3E12, what are the logic levels of test points A, B and C in this circuit? (Assume positive logic.)

A is low, B is high and C is high.

3-35E5 Given the input levels shown in Figure 3E14 and assuming positive logic devices, what would the output be?

A is low, B is high and C is high.

3-20C5 In Figure 3C5, the 1 μF capacitor is connected to a potentiometer that is used to:

Adjust tone.

3-87N1 What causes the SART to begin a transmission?

After being activated the SART responds to RADAR interrogation.

3-96P6 Which of the following conditions can render INMARSAT -B communications impossible?

All of these. An obstruction, such as a mast, causing disruption of the signal between the satellite and the SES antenna when the vessel is steering a certain course. A satellite whose signal is on a low elevation, below the horizon. Travel beyond the effective radius of the satellite.

3-64J2 The voltage produced in a receiving antenna is:

Always proportional to the received field strength.

3-77L3 What does the vertical axis of a spectrum analyzer display?

Amplitude.

3-87N4 Which piece of required GMDSS equipment is the primary source of transmitting locating signals?

An EPIRB transmitting on 406 MHz.

3-5A6 How does the input impedance of a field-effect transistor compare with that of a bipolar transistor?

An FET has high input impedance; a bipolar transistor has low input impedance.

3-72K6 What type of antenna is attached to an aircraft's Mode C transponder installation and used to receive 1030 MHz interrogation signals from the Air Traffic Control Radar Beacon System (ATCRBS)?

An L-band monopole blade-type omnidirectional antenna.

3-19C4 What is the description of an optoisolator?

An LED and a photosensitive device.

3-19C6 What is the description of an optocoupler?

An LED and a photosensitive device.

3-74L6 What instrument may be used to verify proper radio antenna functioning?

An SWR meter.

3-99Q5 Why must you never look directly into a fiber optic cable?

An active fiber signal may burn the retina and infra-red light cannot be seen.

3-71K6 Choose the only correct statement about an aircraft's Automatic Direction Finding (ADF) equipment.

An aircraft's ADF antennas can receive transmissions that are over the Earth's horizon (sometimes several hundred miles away) since these signals will follow the curvature of the Earth.

3-63J5 What is meant by the term radiation resistance of an antenna?

An equivalent resistance that would dissipate the same amount of power as that radiated from an antenna.

3-44F5 If a receiver mixes a 13.8 MHz VFO with a 14.255 MHz receive signal to produce a 455 kHz intermediate frequency signal, what type of interference will a 13.345 MHz signal produce in the receiver?

An image response.

3-94O6 RADAR collision avoidance systems utilize inputs from each of the following except your ship's:

Anemometer.

3-23C2 What are the three terminals of an SCR?

Anode, cathode, and gate.

3-1A1 The product of the readings of an AC voltmeter and AC ammeter is called:

Apparent power.

3-29D1 What is the approximate magnitude of the impedance of a parallel R-L-C circuit at resonance?

Approximately equal to the circuit resistance.

3-29D2 What is the approximate magnitude of the impedance of a series R-L-C circuit at resonance?

Approximately equal to the circuit resistance.

3-39E5 In a microprocessor, what is the meaning of the term "ALU"?

Arithmetical logic unit.

3-94O2 Prior to testing any RADAR system, the operator should first:

Assure no personnel are in front of the antenna.

3-80L2 What is most important when routing cables in a mobile unit?

Assuring radio or electronics cables do not interfere with the normal operation of the vehicle.

3-26C5 For current to flow in an NPN silicon transistor's emitter-collector junction, the base must be:

At least 0.7 volts positive with respect to the emitter.

3-94O3 In the term "ARPA RADAR," ARPA is the acronym for which of the following?

Automatic RADAR Plotting Aid.

3-12B6 Determine the phase relationship between the two signals shown in Figure 3B3.

B is lagging A by 90 degrees.

3-97P4 Which INMARSAT systems offer High Speed Data at 64/54 kbps?

B, M4 and Fleet.

3-16B4 In rectangular coordinates, what is the impedance of a network composed of a 1.0-millihenry inductor in series with a 200-ohm resistor, at 30 kHz?

B. 200 + j188

3-48F2 Which circuit is used to detect FM-phone signals?

BFrequency discriminator.

3-46F4 What parameter must be selected when designing an audio filter using an op-amp?

Bandpass characteristics.

3-25C4 What are the elements of a unijunction transistor?

Base 1, base 2, and emitter.

3-25C2 What are the three terminals of a bipolar transistor?

Base, collector and emitter.

3-40E2 What does the term "BCD" mean?

Binary coded decimal.

3-37E1 The frequency of an AC signal can be divided electronically by what type of digital circuit?

Bistable multivibrator.

3-86N2 What might contribute to apparent low voltage on marine SSB transmitting?

Blown black negative fuse.

3-65J3 An excited 1/2 wavelength antenna produces:

Both electro-magnetic and electro-static fields.

3-31D4 What spectral impurity components might be generated by a phase-locked-loop synthesizer?

Broadband noise.

3-57H4 How can an FM-phone signal be produced in a transmitter?

By feeding the audio directly to the oscillator.

3-56G1 How can intermodulation interference between two transmitters in close proximity often be reduced or eliminated?

By installing a terminated circulator or ferrite isolator in the feed line to the transmitter and duplexer.

3-95P6 How does the COSPAS-SARSAT satellite system determine the position of a ship in distress?

By measuring the Doppler shift of the 406 MHz signal taken at several different points in its orbit.

3-58H5 How can a double-sideband phone signal be produced?

By modulating the supply voltage to a class C amplifier.

3-13B4 In a circuit where the AC voltage and current are out of phase, how can the true power be determined?

By multiplying the apparent power times the power factor.

3-56G2 How can parasitic oscillations be eliminated in a power amplifier?

By neutralization.

3-53G5 How can a single-sideband phone signal be generated?

By using a balanced modulator followed by a filter.

3-42F1 How can selectivity be achieved in the front-end circuitry of a communications receiver?

By using a preselector.

3-56G5 How can even-order harmonics be reduced or prevented in transmitter amplifier design?

By using a push-pull amplifier.

3-82M6 What are the two most-used PCS (Personal Communications Systems) coding techniques used to separate different calls?

CDMA and GSM.

3-96P4 When engaging in voice communications via an INMARSAT-B terminal, what techniques are used?

CODECs are used to digitize the voice signal.

3-4A5 How would you calculate the total capacitance of three capacitors in parallel?

CT = C1 + C2 + C3.

3-55G2 To produce a single-sideband suppressed carrier transmission it is necessary to ____ the carrier and to ____ the unwanted sideband.

Cancel, filter.

3-85N2 What VHF channel is assigned for distress and calling?

Channel 16

3-85N3 What VHF Channel is used for Digital Selective Calling and acknowledgement?

Channel 70

3-51G1 What class of amplifier is distinguished by the presence of output throughout the entire signal cycle and the input never goes into the cutoff region?

Class A.

3-51G3 Which class of amplifier has the highest linearity and least distortion?

Class A.

3-51G6 Which class of amplifier has an operating angle of more than 180 degrees but less than 360 degrees when driven by a sine wave signal?

Class AB.

3-52G6 What class of amplifier is characterized by conduction for 180 degrees of the input wave?

Class B.

3-51G4 Which class of amplifier provides the highest efficiency?

Class C.

3-51G5 What class of amplifier is distinguished by the bias being set well beyond cutoff?

Class C.

3-39E4 What portion of a microprocessor circuit is the pulse generator?

Clock

3-65J6 To lengthen an antenna electrically, add a:

Coil.

3-25C3 What is the meaning of the term "beta" with regard to bipolar transistors? The change of:

Collector current with respect to base current.

3-25C1 What is the meaning of the term "alpha" with regard to bipolar transistors? The change of:

Collector current with respect to emitter current.

3-43F3 What are three major oscillator circuits found in radio equipment?

Colpitts, Hartley, and Pierce.

3-43F4 Which type of oscillator circuit is commonly used in a VFO (variable frequency oscillator)?

Colpitts.

3-30D5 Which of the following op-amp circuits is operated open-loop?

Comparator.

3-28C3 What do the initials CMOS stand for?

Complementary metal-oxide semiconductor.

3-41F3 What is the term used to refer to a reduction in receiver sensitivity caused by unwanted high-level adjacent channel signals?

Desensitizing.

3-78L5 A communications technician would perform a modulation-acceptance bandwidth test in order to:

Determine the effective bandwidth of a communications receiver.

3-70K6 On runway approach, an ILS Localizer shows:

Deviation left or right of runway center line.

3-57H6 In an FM-phone signal, what is the term for the maximum deviation from the carrier frequency divided by the maximum audio modulating frequency?

Deviation ratio.

3-66J2 What determines the velocity factor in a transmission line?

Dielectrics in the line.

3-49F3 What makes a Digital Coded Squelch work?

Digital codes.

3-39E2 What does the term "DAC" refer to in a microprocessor circuit?

Digital to analog converter.

3-95P3 What services are provided by the Iridium system?

Digital voice and Data at 2.4 kbps.

3-82M2 Name two types of spread spectrum systems used in most RF communications applications?

Direct Sequence and Frequency Hopping.

3-48F5 In a CTCSS controlled FM receiver, the CTCSS tone is filtered out after the:

Discriminator but before the audio section.

3-68K5 What radio navigation aid determines the distance from an aircraft to a selected VORTAC station by measuring the length of time the radio signal takes to travel to and from the station?

Distance Measuring Equipment (DME).

3-20C1 What factors determine the capacitance of a capacitor?

Distance between the plates and the dielectric constant of the material between the plates.

3-40E1 What is the purpose of a prescaler circuit?

Divides an HF signal so that a low-frequency counter can display the operating frequency.

3-45F4 A receiver selectivity of 10 KHz in the IF circuitry is optimum for what type of signals?

Double-sideband AM.

3-13B2 If a resistance to which a constant voltage is applied is halved, what power dissipation will result?

Double.

3-73K2 Aviation services use predominantly ____ microphones.

Dynamic

3-41F6 What is the term for the ratio between the largest tolerable receiver input signal and the minimum discernible signal?

Dynamic range.

3-84M4 Which is the code used for SITOR-A and -B transmissions?

Each character consists of 7 bits with 4 "zeros" and 3 "ones".

3-91O3 What device can be used to determine the performance of a RADAR system at sea?

Echo box.

3-91O2 What is the purpose or function of the RADAR duplexer/circulator? It is a/an:

Electronic switch that allows the use of one antenna for both transmission and reception.

3-60I1 When a lead-acid storage battery is being charged, a harmful effect to humans is:

Emission of hydrogen gas.

3-25C5 The beta cutoff frequency of a bipolar transistor is the frequency at which:

Emitter current gain has decreased to 0.707 of maximum.

3-89N5 An NMEA 2000 system with devices in a single location may be powered using this method:

End-powered network.

3-73K4 Before ground testing an aircraft RADAR, the operator should:

Ensure that the area in front of the antenna is clear of other maintenance personnel to avoid radiation hazards.

3-65J1 A vertical 1/4 wave antenna receives signals:

Equally from all horizontal directions.

3-100Q4 What class of fire is one that is caused by an electrical short circuit and what is the preferred substance used to extinguish that type of fire?

FE30.

3-4A3 Which of the 4 groups of metals listed below are the best low-resistance conductors?

Gold, silver, and copper.

3-80L1 What color is the binder for pairs 51-75 in a 100-pair cable?

Green

3-43F5 What condition must exist for a circuit to oscillate? It must:

Have sufficient positive feedback.

3-42F5 What is the advantage of a GaAsFET preamplifier in a modern VHF radio receiver?

High gain and low noise floor.

3-35E4 In a positive-logic circuit, what level is used to represent a logic 1?

High level

3-35E1 In a negative-logic circuit, what level is used to represent a logic 0?

High level.

3-47F3 What are the three general groupings of filters?

High-pass, low-pass and band-pass.

3-73K5 What type of antenna is used in an aircraft's Very High Frequency Omnidirectional Range (VOR) and Localizer (LOC) installations?

Horizontally polarized omnidirection reception antenna.

3-9B2 Which of the following Ohms Law formulas is incorrect?

I = R / E

3-97P5 When INMARSAT-B and INMARSAT-C terminals are compared:

INMARSAT-C antennas are small and omni-directional, while INMARSAT-B antennas are larger and directional.

3-24C6 What is the principal characteristic of a tunnel diode?

Negative resistance region.

3-26C6 When an NPN transistor is operating as a Class A amplifier, the base-emitter junction:

Is forward biased and the collector-base junction is reverse biased.

3-63J3 A radio frequency device that allows RF energy to pass through in one direction with very little loss but absorbs RF power in the opposite direction is a:

Isolator.

3-46F5 What are the distinguishing features of a Chebyshev filter?

It allows ripple in the passband.

3-8A2 What happens to reactive power in a circuit that has both inductors and capacitors?

It alternates between magnetic and electric fields and is not dissipated.

3-20C6 What is the purpose of a coupling capacitor?

It blocks direct current and passes alternating current.

3-85N5 What is the reason for the USA-INT control or function?

It changes some channels that are normally duplex channels into simplex channels.

3-53G4 How does the modulation index of a phase-modulated emission vary with RF carrier frequency?

It does not depend on the RF carrier frequency.

3-47F6 What are the distinguishing features of a Butterworth filter?

It has a maximally flat response over its passband.

3-47F5 What is an advantage of a constant-k filter?

It has high attenuation of signals at frequencies far removed from the pass band.

3-30D2 What are the characteristics of an inverting operational amplifier (op-amp) circuit?

It has input and output signals 180 degrees out of phase.

3-19C1 What happens to the conductivity of photoconductive material when light shines on it?

It increases.

3-81L5 How might an installer verify correct GPS sentence to marine DSC VHF radio?

Look for latitude and longitude on the display.

3-85N6 How might an installer verify correct GPS sentence to marine DSC VHF radio?

Look for latitude and longitude, plus speed, on VHF display.

3-69K1 All directions associated with a VOR station are related to:

Magnetic north.

3-91O6 The component or circuit providing the transmitter output power for a RADAR system is the:

Magnetron.

3-4A2 Good conductors with minimum resistance have what type of electrons?

Many free electrons.

3-57H1 The deviation ratio is the:

Maximum carrier frequency deviation to the highest audio modulating frequency.

3-5A1 What are the two most commonly-used specifications for a junction diode?

Maximum forward current and PIV (peak inverse voltage).

3-64J4 At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna?

Maximum voltage and minimum current.

3-29D4 What is the characteristic of the current flow in a series R-L-C circuit at resonance?

Maximum.

3-29D5 What is the characteristic of the current flow within the parallel elements in a parallel R-L-C circuit at resonance?

Maximum.

3-78L4 What is the common method for determining the exact sensitivity specification of a receiver?

Measure the recovered audio for 12 dB of SINAD.

3-76L5 An oscilloscope can be used to accomplish all of the following except:

Measure velocity of light with the aid of a light emitting diode.

3-28C4 What is the piezoelectric effect?

Mechanical vibration of a crystal by the application of a voltage.

3-3A6 Which of these will be most useful for insulation at UHF frequencies?

Mica.

3-71K4 In addition to duplicating the functions of a mode C transponder, an aircraft's mode S transponder can also provide:

Mid-Air collision avoidance capabilities.

3-45F6 How should the filter bandwidth of a receiver IF section compare with the bandwidth of a received signal?

Slightly greater than the received-signal bandwidth.

3-93O4 A common shipboard RADAR antenna is the:

Slotted array.

3-84M1 What is a SDR?

Software Defined Radio.

3-82M1 What term describes a wide-bandwidth communications system in which the RF carrier frequency varies according to some predetermined sequence?

Spread spectrum communication.

3-56G6 What is the modulation type that can be a frequency hopping of one carrier or multiple simultaneous carriers?

Spread spectrum.

3-56G4 What term describes a wide-bandwidth communications system in which the RF carrier varies according to some pre-determined sequence?

Spread-spectrum communication.

3-44F6 What might occur in a receiver if excessive amounts of signal energy overdrive the mixer circuit?

Spurious mixer products are generated.

3-31D5 In a direct digital synthesizer, what are the unwanted components on its output?

Spurs at discrete frequencies.

3-37E6 What wave form would appear on the voltage outputs at the collectors of an astable, multivibrator, common-emitter stage?

Square wave.

3-3A3 Which metal object may be least affected by galvanic corrosion when submerged in seawater?

Stainless steel propeller shaft.

3-42F3 How much gain should be used in the RF amplifier stage of a receiver?

Sufficient gain to allow weak signals to overcome noise generated in the first mixer stage.

3-42F4 Too much gain in a VHF receiver front end could result in this:

Susceptibility of intermodulation interference from nearby transmitters.

3-76L4 What factors limit the accuracy, frequency response, and stability of an oscilloscope?

Sweep oscillator quality and deflection amplifier bandwidth.

3-22C2 A switching electronic voltage regulator:

Switches the control device on or off, with the duty cycle proportional to the line or load conditions.

3-59H1 What is an important factor in pulse-code modulation using time-division multiplex?

Synchronization of transmit and receive clock pulse rates.

3-73K6 What is the function of a commercial aircraft's SELCAL installation? SELCAL is a type of aircraft communications __________.

System where a ground-based transmitter can call a selected aircraft or group of aircraft without the flight crew monitoring the ground-station frequency.

3-23C3 Which of the following devices acts as two SCRs connected back to back, but facing in opposite directions and sharing a common gate?

TRIAC.

3-23C4 What is the transistor called that is fabricated as two complementary SCRs in parallel with a common gate terminal?

TRIAC.

3-89N2 How should shielding be grounded on an NMEA 0183 data line?

Terminated to ground at the talker and unterminated at the listener.

3-21C5 A power transformer has a single primary winding and three secondary windings producing 5.0 volts, 12.6 volts, and 150 volts. Assuming similar wire sizes, which of the three secondary windings will have the highest measured DC resistance?

The 150 volt winding.

3-73K1 Some aircraft and avionics equipment operates with a prime power line frequency of 400 Hz. What is the principle advantage of a higher line frequency?

The magnetic devices in a 400 Hz power supply such as transformers, chokes and filters are smaller and lighter than those used in 60 Hz power supplies.

3-27C2 What determines the visible color radiated by an LED junction?

The materials used to construct the device.

3-41F1 What is the limiting condition for sensitivity in a communications receiver?

The noise floor of the receiver.

3-30D3 Gain of a closed-loop op-amp circuit is determined by?

The op-amp's external feedback network.

3-44F4 What are the principal frequencies that appear at the output of a mixer circuit?

The original frequencies and the sum and difference frequencies.

3-76L2 How does a spectrum analyzer differ from a conventional oscilloscope?

The oscilloscope is used to display electrical signals in the time domain while the spectrum analyzer is used to display electrical signals in the frequency domain.

3-93O5 Conductance takes place in a waveguide:

Through electromagnetic and electrostatic fields in the walls of the waveguide.

3-84M6 What principle allows multiple conversations to be able to share one radio channel on a GSM channel?

Time Division Multiplex.

3-42F2 What is the primary purpose of an RF amplifier in a receiver?

To improve the receiver's noise figure.

3-75L1 How is a frequency counter used?

To measure the time between events, or the frequency, which is the reciprocal of the time.

3-100Q6 What is a GFI electrical socket used for?

To prevent electrical shock by sensing ground path current and shutting the circuit down.

3-49F5 What makes a CTCSS squelch work?

Tones.

3-33E6 What do the initials TTL stand for?

Transistor-transistor logic.

3-71K3 What are the transmit and receive frequencies of an aircraft's mode C transponder operating in the Air Traffic Control RADAR Beacon System (ATCRBS)?

Transmit at 1090 MHz, and receive at 1030 MHz

3-87N6 What statement is true regarding 406 MHz EPIRB transmissions?

Transmits a unique hexadecimal identification number.

3-91O4 What is the purpose of a synchro transmitter and receiver?

Transmits the angular position of the antenna to the indicator unit.

3-24C4 What special type of diode is capable of both amplification and oscillation?

Tunnel diodes.

3-58H6 What type of signals are used to conduct an SSB two-tone test?

Two non-harmonically related audio signals that are within the modulation band pass of the transmitter.

3-86N5 The sequence ARQ, FEC, SFEC best corresponds to which of the following sequences?

Two way communications, one-way communications to all stations, one-way communications to a single station.

3-86N6 Which of the following statements concerning SITOR communications is true?

Two-way communication with the coast radio station using FEC is not necessary to be able to receive the broadcasts.

3-92O4 What pulse width and repetition rate should you use at long ranges?

Wide pulse width and slow repetition rate.

3-79L3 What is the proper way to cut plastic wire ties?

With flush-cut diagonal pliers and cut flush.

3-1A5 What formula would determine the inductive reactance of a coil if frequency and coil inductance are known?

XL = 2f L

3-99Q6 If the MPE (Maximum Permissible Exposure) power is present, how often must the personnel accessing the affected area be trained and certified?

Yearly.

3-78L1 Can a P25 radio system be monitored with a scanner?

Yes, if the scanner has P25 decoding.

3-22C4 In a regulated power supply, what type of component will most likely be used to establish a reference voltage?

Zener Diode.

3-22C3 What device is usually used as a stable reference voltage in a linear voltage regulator?

Zener diode.

3-5A3 MOSFETs are manufactured with THIS protective device built into their gate to protect the device from

Zener diode.

3-33E1 What is the voltage range considered to be valid logic low input in a TTL device operating at 5 volts?

Zero to 0.8 volts.

3-3A1 What metal is usually employed as a sacrificial anode for corrosion control purposes?

Zinc bar.

3-54G6 Which network provides the greatest harmonic suppression?

Pi-L network.

3-28C6 In which oscillator circuit would you find a quartz crystal?

Pierce

3-65J2 The resonant frequency of a Hertz antenna can be lowered by:

Placing an inductance in series with the antenna.

3-75L3 What equipment may be useful to track down EMI aboard a ship or aircraft?

Portable AM receiver.

3-49F4 What causes a squelch circuit to function?

Presence of noise.

3-66J3 Nitrogen is placed in transmission lines to:

Prevent moisture from entering the line.

3-94O1 The permanent magnetic field that surrounds a traveling-wave tube (TWT) is intended to:

Prevent the electron beam from spreading.

3-91O1 The ATR box:

Prevents the received signal from entering the transmitter.

3-40E3 What is the function of a decade counter digital IC?

Produce one output pulse for every ten input pulses.

3-34E4 What is a characteristic of a NOR gate?

Produces a logic "0" at its output if any or all inputs are logic "1".

3-34E2 What is a characteristic of a NAND gate?

Produces a logic "0" at its output only when all inputs are logic "1".

3-34E5 What is a characteristic of a NOT gate?

Produces a logic "0" at its output when the input is logic "1" and vice versa.

3-34E3 What is a characteristic of an OR gate?

Produces a logic "1" at its output if any input is logic "1".

3-34E1 What is a characteristic of an AND gate?

Produces a logic "1" at its output only if all inputs are logic "1".

3-70K5 Choose the only correct statement about the localizer beam system used by aircraft to find the centerline of a runway during an Instrument Landing System (ILS) approach to an airport. The localizer beam system:

Produces two amplitude modulated antenna patterns; one pattern with an audio frequency of 90 Hz and one pattern with an audio frequency of 150 Hz, one left of the runway centerline and one right of the runway centerline.

3-38E4 What is the name for a microprocessor's sequence of commands and instructions?

Program.

3-85N4 Maximum allowable frequency deviation for VHF marine radios is:

+/- 5 kHz.

3-12B2 At 150 degrees, what is the amplitude of a sine-wave having a peak value of 5 volts?

+2.5 volts.

3-12B1 At pi/3 radians, what is the amplitude of a sine-wave having a peak value of 5 volts?

+4.3 volts.

3-12B3 At 240 degrees, what is the amplitude of a sine-wave having a peak value of 5 volts?

-4.3 volts.

3-32D1 Given the combined DC input voltages, what would the output voltage be in the circuit shown in Figure 3D7?

-5.5 V

3-6A5 By what factor must the voltage measured in an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the average voltage value?

. 0.9

3-6A2 By what factor must the voltage of an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the peak voltage value?

. 1.414

3-6A6 What is the peak voltage at a common household electrical outlet?

. 165.5 volts.

3-9B4 If a 100-ohm resistor is connected across 200 volts, what is the current through the resistor?

. 2 amperes.

3-10B2 What is the maximum DC or RMS voltage that may be connected across a 20 watt, 2000 ohm resistor?

. 200 volts.

3-55G6 What would be the voltage across a 50-ohm dummy load dissipating 1,200 watts?

. 245 volts.

3-9B5 If a current of 3 amperes flows through a resistor connected to 90 volts, what is the resistance?

. 30 ohms.

3-7A2 How many degrees are there in one complete sine wave cycle?

. 360 degrees.

3-9B1 What value of series resistor would be needed to obtain a full scale deflection on a 50 microamp DC meter with an applied voltage of 200 volts DC?

. 4 megohms.

3-47F2 Which statement is true regarding the filter output characteristics shown in Figure 3F16?

. A is a low pass curve and D is a band stop curve.

3-81L3 A common method of programming portable or mobile radios is to use a:

. A laptop computer.

3-35E6 What is a truth table?

. A list of input combinations and their corresponding outputs that characterizes a digital device's function.

3-54G2 What is a pi-network?

. A network consisting of one inductor and two capacitors or two inductors and one capacitor.

3-92O6 When a RADAR is being operated on the 1.5 mile range setting, what is the most appropriate pulse width and pulse repetition rate?

0.05 s PW and 2,000 pps.

3-74L2 A 50 microampere meter movement has an internal resistance of 2,000 ohms. What applied voltage is required to indicate half-scale deflection?

0.05 volts.

3-92O2 When a RADAR is being operated on the 6 mile range setting what is the most appropriate pulse width and pulse repetition rate?

0.25 s PW and 1,000 pps.

3-10B6 What is the maximum rated current-carrying capacity of a resistor marked "2000 ohms, 200 watts"?

0.316 amps.

3-61I2 What current will flow in a 6 volt storage battery with an internal resistance of 0.01 ohms, when a 3-watt, 6-volt lamp is connected?

0.4995 amps.

3-13B1 What does the power factor equal in an R-L circuit having a 60 degree phase angle between the voltage and the current?

0.5

3-18B6 What is the conductance (G) of a circuit if 6 amperes of current flows when 12 volts DC is applied?

0.50 Siemens (mhos).

3-13B5 What does the power factor equal in an R-L circuit having a 45 degree phase angle between the voltage and the current?

0.707

3-61I5 A 6 volt battery with 1.2 ohms internal resistance is connected across two light bulbs in parallel whose resistance is 12 ohms each. What is the current flow?

0.83 amps.

3-13B6 What does the power factor equal in an R-L circuit having a 30 degree phase angle between the voltage and the current?

0.866

3-40E6 In binary numbers, how would you note the quantity TWO?

0010

3-36E4 How many bits of information can be stored in a single flip-flop circuit?

1

3-3A2 What is the relative dielectric constant for air?

1

3-61I4 If a marine radiotelephone receiver uses 75 watts of power and a transmitter uses 325 watts, how long can they both operate before discharging a 50 ampere-hour 12 volt battery?

1 1/2 hours.

3-61I3 A ship RADAR unit uses 315 watts and a radio uses 50 watts. If the equipment is connected to a 50 ampere-hour battery rated at 12.6 volts, how long will the battery last?

1 hour 43 minutes.

3-88N3 What would be the bandwidth of a good crystal lattice band-pass filter for weather facsimile HF (high frequency) reception?

1 kHz at -6 dB.

3-66J4 A perfect (no loss) coaxial cable has 7 dB of reflected power when the input is 5 watts. What is the output of the transmission line?

1 watt.

3-92O1 When a RADAR is being operated on the 48 mile range setting, what is the most appropriate pulse width (PW) and pulse repetition rate (pps)?

1.0 s PW and 500 pps.

3-92O3 We are looking at a target 25 miles away. When a RADAR is being operated on the 25 mile range setting what is the most appropriate pulse width and pulse repetition rate?

1.0 s PW and 500 pps.

3-60I6 A nickel-cadmium cell has an operating voltage of about:

1.25 volts.

3-89N6 What voltage drop at the end of the last segment will satisfy NMEA 2000 network cabling plans?

1.5 volts

3-57H2 What is the deviation ratio for an FM phone signal having a maximum frequency deviation of plus or minus 5 kHz and accepting a maximum modulation rate of 3 kHz?

1.66

3-61I1 When an emergency transmitter uses 325 watts and a receiver uses 50 watts, how many hours can a 12.6 volt, 55 ampere-hour battery supply full power to both units?

1.8 hours.

3-69K5 The amplitude modulated variable phase signal and the frequency modulated reference phase signal of a Very-high-frequency Omnidirectional Range (VOR) station used for aircraft navigation are synchronized so that both signals are in phase with each other at ____________ of the VOR station.

360 degrees North, magnetic bearing position.

3-67J3 What is the effective radiated power of a repeater with 75 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna gain?

37.6 watts.

3-9B6 A relay coil has 500 ohms resistance, and operates on 125 mA. What value of resistance should be connected in series with it to operate from 110 V DC?

380 ohms.

3-67J1 What is the effective radiated power of a repeater with 50 watts transmitter power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 6 dB antenna gain?

39.7 watts.

3-50F5 In Figure 3F15 at what point in the circuit (labeled 1 through 4) could a DC voltmeter be used to monitor signal strength?

4

3-98P5 How many satellites must be received to provide complete position and time?

4

3-16B3 In rectangular coordinates, what is the impedance of a network composed of a 10-microhenry inductor in series with a 40-ohm resistor, at 500 MHz?

40 +j31400

3-16B6 In rectangular coordinates, what is the impedance of a network composed of a 0.001-microfarad capacitor in series with a 400-ohm resistor, at 500 kHz?

400 - j318

3-72K5 What is the frequency range of an aircraft's radio altimeter?

4250 MHz to 4350 MHz.

3-11B1 What is the most the actual transmit frequency could differ from a reading of 462,100,000 Hertz on a frequency counter with a time base accuracy of ± 0.1 ppm?

46.21 Hz.

3-11B6 What is the most the actual transmitter frequency could differ from a reading of 462,100,000 hertz on a frequency counter with a time base accuracy of ± 1.0 ppm?

462.1 Hz.

3-15B2 What is the time constant of a circuit having two 100-microfarad capacitors and two 470-kilohm resistors all in series?

47 seconds.

3-15B3 What is the time constant of a circuit having a 100-microfarad capacitor and a 470-kilohm resistor in series?

47 seconds.

3-15B5 What is the time constant of a circuit having two 100-microfarad capacitors and two 470-kilohm resistors all in parallel?

47 seconds.

3-95P1 What is the orbiting altitude of the Iridium satellite communications system?

485 miles.

3-99Q2 Sites having multiple transmitting antennas must include antennas with more than _______% of the maximum permissible power density exposure limit when evaluating RF site exposure.

5

3-90O6 If the elapsed time for a RADAR echo is 62 microseconds, what is the distance in nautical miles to the object?

5 nautical miles.

3-10B4 In Figure 3B1, what is the voltage drop across R1?

5 volts.

3-33E3 What is the common power supply voltage for TTL series integrated circuits?

5 volts.

3-94O5 Exposure to microwave energy from RADAR or other electronics devices is limited by U.S. Health Department regulations to _______ mW/centimeter.

5.0

3-78L6 What is the maximum FM deviation for voice operation of a normal wideband channel on VHF and UHF?

5.0 kHz

3-89N4 In an NMEA 2000 device, a load equivalence number (LEN) of 1 is equivalent to how much current consumption?

50 mA

3-21C6 A power transformer has a primary winding of 200 turns of #24 wire and a secondary winding consisting of 500 turns of the same size wire. When 20 volts are applied to the primary winding, the expected secondary voltage will be:

50 volts.

3-31D3 RF input to a mixer is 200 MHz and the local oscillator frequency is 150 MHz. What output would you expect to see at the IF output prior to any filtering?

50, 150, 200 and 350 MHz.

3-17B3 In polar coordinates, what is the impedance of a network composed of a 400-ohm-reactance capacitor in series with a 300-ohm resistor?

500 ohms, /-53.1 degrees

3-17B4 In polar coordinates, what is the impedance of a network composed of a 300-ohm-reactance capacitor, a 600-ohm-reactance inductor, and a 400-ohm resistor, all connected in series?

500 ohms, /37 degrees

3-90O1 What is the normal range of pulse repetition rates?

500 to 2,000 pps.

3-88N5 Which of the following is the primary frequency that is used exclusively for NAVTEX broadcasts internationally?

518 kHz.

3-62I4 What is the line current of a 7 horsepower motor operating on 120 volts at full load, a power factor of 0.8, and 95% efficient?

57.2 amps.

3-64J1 What is the current flowing through a 52 ohm line with an input of 1,872 watts?

6 amps.

3-66J6 If a transmission line has a power loss of 6 dB per 100 feet, what is the power at the feed point to the antenna at the end of a 200 foot transmission line fed by a 100 watt transmitter?

6 watts.

3-99Q1 Compliance with MPE, or Maximum Permissible Exposure to RF levels (as defined in FCC Part 1, OET Bulletin 65) for "controlled" environments, are averaged over _______ minutes, while "uncontrolled" RF environments are averaged over ______ minutes.

6, 30.

3-14B2 What is the meaning of the term "time constant of an RC circuit"? The time required to charge the capacitor in the circuit to:

63.2% of the supply voltage.

3-38E5 How many individual memory cells would be contained in a memory IC that has 4 data bus input/output pins and 4 address pins for connection to the address bus?

64

3-23C6 What circuit might contain a SCR?

A light-dimming circuit.

3-68K4 What is the main underlying operating principle of an aircraft's Distance Measuring Equipment (DME)?

A measurable amount of time is required to send and receive a radio signal through the Earth's atmosphere.

3-53G6 What is a balanced modulator?

A modulator that produces a double sideband, suppressed carrier signal.

3-54G1 What is an L-network?

A network consisting of an inductor and a capacitor.

3-54G5 What is a pi-L network?

A network consisting of two inductors and two capacitors.

3-69K6 What is the main underlying operating principle of the Very-high-frequency Omnidirectional Range (VOR) aircraft navigational system?

A phase difference between two AC voltages may be used to determine an aircraft's azimuth position in relation to a selected VOR station.

3-41F2 What is the definition of the term "receiver desensitizing"?

A reduction in receiver sensitivity because of a strong signal on a nearby frequency.

3-87N2 How should the signal from a Search And Rescue RADAR Transponder appear on a RADAR display?

A series of 12 equally spaced dots.

3-31D6 What is the definition of a phase-locked loop (PLL) circuit?

A servo loop consisting of a phase detector, a low-pass filter and voltage-controlled oscillator.4

3-77L5 What test instrument can be used to display spurious signals in the output of a radio transmitter?

A spectrum analyzer.

3-59H6 What is one way that voice is transmitted in a pulse-width modulation system?

A standard pulse is varied in duration by an amount depending on the voice waveform at that instant.

3-98P6 What is DGPS?

A system to provide additional correction factors to improve position accuracy.

3-93O6 To couple energy into and out of a waveguide use:

A thin piece of wire as an antenna.

3-58H3 What kind of input signal could be used to test the amplitude linearity of a single-sideband phone transmitter while viewing the output on an oscilloscope?

A two-tone audio-frequency sine wave.

3-2A5 What is meant by the term "back EMF"?

A voltage that opposes the applied EMF.

3-40E4 What integrated circuit device converts an analog signal to a digital signal?

ADC

3-83M5 What CODEC is used in Phase 2 P25 radios?

AMBE

3-34E6 Which of the following logic gates will provide an active high out when both inputs are active high?

AND.

3-96P2 Which of the following describes the INMARSAT Satellite system?

AOR-E at 15.5 W, AOR-W at 54 W, POR at 178 E and IOR at 64.5 E.

3-86N4 Which of the following statements concerning SITOR communications is true?

ARQ message transmissions are made in data groups consisting of three-character blocks.

3-83M3 Which of the following codes has gained the widest acceptance for exchange of data from one computer to another?

ASCII.

3-49F1 What is the digital signal processing term for noise subtraction circuitry?

Adaptive filtering and autocorrelation.

3-81L2 The tachometer of a building's elevator circuit experiences interference caused by the radio system nearby. What is a common potential "fix" for the problem?

Add a .01 μF capacitor across the motor/tachometer leads.

3-65J4 To increase the resonant frequency of a 1/4 wavelength antenna:

Add a capacitor in series.

3-22C5 A three-terminal regulator:

Contains a voltage reference, error amplifier, sensing resistors and transistors, and a pass element.

3-84M2 What does the DSP not do in a modern DSP radio?

Control SWR.

3-50F3 What is the term used to refer to the condition where the signals from a very strong station are superimposed on other signals being received?

Cross-modulation interference.

3-40E5 What integrated circuit device converts digital signals to analog signals?

DAC

3-38E6 What is the name of the random-accessed semiconductor memory IC that must be refreshed periodically to maintain reliable data storage in its memory matrix?

DRAM - Dynamic Random-Access Memory.

3-39E6 What circuit interconnects the microprocessor with the memory and input/output system?

Data bus line.

3-20C2 In Figure 3C4, if a small variable capacitor were installed in place of the dashed line, it would?

Decrease parasitic oscillations.

3-93O3 What happens to the beamwidth of an antenna as the gain is increased? The beamwidth:

Decreases as the gain is increased.

3-37E4 What is a bistable multivibrator circuit commonly named?

Flip-flop.

3-37E5 What is a bistable multivibrator circuit?

Flip-flop.

3-79L5 A "hot gas bonder" is used:

For non-contact melting of solder.

3-27C1 What type of bias is required for an LED to produce luminescence?

Forward bias.

3-77L4 What instrument is most accurate when checking antennas and transmission lines at the operating frequency of the antenna?

Frequency domain reflectometer.

3-82M3 What is the term used to describe a spread spectrum communications system where the center frequency of a conventional carrier is altered many times per second in accordance with a pseudo-random list of channels?

Frequency hopping.

3-30D6 In the op-amp oscillator circuit shown in Figure 3D6, what would be the most noticeable effect if the capacitance of C were suddenly doubled?

Frequency would be lower.

3-77L2 What does the horizontal axis of a spectrum analyzer display?

Frequency.

3-30D4 Where is the external feedback network connected to control the gain of a closed-loop op-amp circuit?

From output to the inverting input.

3-42F6 In what stage of a VHF receiver would a low noise amplifier be most advantageous?

Front end RF stage.

3-80L6 What type of wire would connect an SSB automatic tuner to an insulated backstay?

GTO-15 high-voltage cable.

3-86N3 What type of wire connects an SSB automatic tuner to an insulated backstay?

GTO-15 high-voltage cable.

3-93O1 How does the gain of a parabolic dish antenna change when the operating frequency is doubled?

Gain increases 6 dB.

3-46F1 What is the primary purpose of the final IF amplifier stage in a receiver?

Gain.

3-3A5 Corrosion resulting from electric current flow between dissimilar metals is called:

Galvanic corrosion.

3-23C5 What are the three terminals of a TRIAC?

Gate, anode 1, and anode 2.

3-46F2 What factors should be considered when selecting an intermediate frequency?

Image rejection and selectivity.

3-21C1 A capacitor is sometimes placed in series with the primary of a power transformer to:

Improve the power factor.

3-91O5 Digital signal processing (DSP) of RADAR signals (compared with analog) causes:

Improved weak signal or target enhancement.

3-23C1 How might two similar SCRs be connected to safely distribute the power load of a circuit?

In parallel, reverse polarity.

3-78L3 What is a common method used to program radios without using a "wired" connection?

Infra-red communication.

3-81L6 What steps must be taken to activate the DSC emergency signaling function on a marine VHF?

Input of registered 9-digit MMSI.

3-50F2 How can ferrite beads be used to suppress ignition noise? Install them:

Install them in the primary and secondary ignition leads.

3-50F6 Pulse type interference to automobile radio receivers that appears related to the speed of the engine can often be reduced by:

Installing resistances in series with spark plug wires.

3-56G3 What is the name of the condition that occurs when the signals of two transmitters in close proximity mix together in one or both of their final amplifiers, and unwanted signals at the sum and difference frequencies of the original transmissions are generated?

Intermodulation interference.

3-28C1 What describes a diode junction that is forward biased?

It is a low impedance.

3-97P1 What is the best description for the INMARSAT-C system?

It is a store-and-forward system that provides routine and distress communications.

3-65J5 What happens to the bandwidth of an antenna as it is shortened through the use of loading coils?

It is decreased.

3-43F1 Why is the Colpitts oscillator circuit commonly used in a VFO (variable frequency oscillator)?

It is stable.

3-74L4 What is the purpose of a shunt resistor used with an ammeter?

It is used to increase the ampere indicating range of the ammeter.

3-74L3 What is the purpose of a series multiplier resistor used with a voltmeter?

It is used to increase the voltage-indicating range of the voltmeter.

3-63J4 What is an advantage of using a trap antenna?

It may be used for multiband operation.

3-4A4 What is the purpose of a bypass capacitor?

It removes alternating current by providing a low impedance path to ground.

3-62I1 What occurs if the load is removed from an operating series DC motor?

It will accelerate until it falls apart.

3-62I2 If a shunt motor running with a load has its shunt field opened, how would this affect the speed of the motor?

It will speed up.

3-93O2 What type of antenna or pickup device is used to extract the RADAR signal from the wave guide?

J-hook.

3-1A3 What is the term used to express the amount of electrical energy stored in an electrostatic field?

Joules.

3-24C3 Structurally, what are the two main categories of semiconductor diodes?

Junction and point contact.

3-80L5 What tolerance off of plumb should a single base station radio rack be installed?

Just inside the bubble on a level.

3-94O4 Which of the following is NOT a precaution that should be taken to ensure the magnetron is not weakened:

Keep the TR properly tuned.

3-63J2 Why is the value of the radiation resistance of an antenna important?

Knowing the radiation resistance makes it possible to match impedances for maximum power transfer.

3-54G4 Which three network types are commonly used to match an amplifying device to a transmission line?

L network, pi network and pi-L network.

3-4A1 What formula would calculate the total inductance of inductors in series?

LT = L1 + L2

3-2A3 When induced currents produce expanding magnetic fields around conductors in a direction that opposes the original magnetic field, this is known as:

Lenz's law.

3-52G3 The class C amplifier output is present for what portion of the input cycle?

Less than 180 degrees.

3-100Q2 What is the purpose of not putting sharp corners on the ground leads within a building?

Lightning will jump off of the ground lead because it is not able to make sharp bends.

3-58H4 What does a two-tone test illustrate on an oscilloscope?

Linearity of a SSB transmitter.

3-83M6 The International Organization for Standardization has developed a seven-level reference model for a packet-radio communications structure. The _______ level arranges the bits into frames and controls data flow.

Link layer.

3-70K3 Which of the following is a required component of an Instrument Landing System (ILS)?

Localizer: shows aircraft deviation horizontally from center of runway.

3-33E5 Which of the following instruments would be best for checking a TTL logic circuit?

Logic probe.

3-74L5 What instrument is used to indicate high and low digital voltage states?

Logic probe.

3-14B1 What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the supply voltage?

One time constant.

3-14B3 What is the term for the time required for the current in an RL circuit to build up to 63.2% of the maximum value?

One time constant.

3-30D1 What is the main advantage of using an op-amp audio filter over a passive LC audio filter?

Op-amps exhibit gain rather than insertion loss.

3-36E6 An R-S flip-flop is capable of doing all of the following except:

Operate in toggle mode with R-S inputs held constant and CLK initiated.

3-27C5 An LED facing a photodiode in a light-tight enclosure is commonly known as a/an:

Optoisolator.

3-77L1 A(n) ____ and ____ can be combined to measure the characteristics of transmission lines. Such an arrangement is known as a time-domain reflectometer (TDR).

Oscilloscope, pulse generator.

3-76L6 What instrument is used to check the signal quality of a single-sideband radio transmission?

Oscilloscope.

3-51G2 What is the distinguishing feature of a Class A amplifier?

Output for the entire 360 degrees of the signal cycle.

3-74L1 What is a 1/2 digit on a DMM?

Partial extended accuracy on lower part of the range.

3-52G2 What input-amplitude parameter is most valuable in evaluating the signal-handling capability of a Class A amplifier?

Peak voltage.

3-31D2 A circuit that compares the output of a voltage-controlled oscillator (VCO) to a frequency standard and produces an error voltage that is then used to adjust the capacitance of a varactor diode used to control frequency in that same VCO is called what?

Phase-locked loop.

3-59H2 In a pulse-width modulation system, what parameter does the modulating signal vary?

Pulse duration.

3-71K5 What type of encoding is used in an aircraft's mode C transponder transmission to a ground station of the Air Traffic Control RADAR Beacon System (ATCRBS)?

Pulse position modulation.

3-90O5 The pulse repetition rate (prr) of a RADAR refers to the:

Pulse rate of the magnetron.

3-59H3 What is the name of the type of modulation in which the modulating signal varies the duration of the transmitted pulse?

Pulse-width modulation.

3-38E1 What is the name of the semiconductor memory IC whose digital data can be written or read, and whose memory word address can be accessed randomly?

RAM - Random-Access Memory.

3-3A4 Skin effect is the phenomenon where:

RF current flows in a thin layer of the conductor, closer to the surface, as frequency increases.

3-99Q3 RF exposure from portable radio transceivers may be harmful to the eyes because:

RF heating may cause cataracts.

3-24C1 What is one common use for PIN diodes?

RF switch.

3-44F3 In what radio stage is the image frequency normally rejected?

RF.

3-38E2 What is the name of the semiconductor IC that has a fixed pattern of digital data stored in its memory matrix?

ROM - Read-Only Memory.

3-69K4 Lines drawn from the VOR station in a particular magnetic direction are:

Radials.

3-1A6 What is the term for the out-of-phase power associated with inductors and capacitors?

Reactive power.

3-45F2 Which one of these filters can be used in micro-miniature electronic circuits?

Receiver SAW IF filter.

3-88N4 Which of the following statements about NAVTEX is true?

Receives MSI broadcasts using SITOR-B or FEC mode.

3-48F3 What is the process of detection in a radio diode detector circuit?

Rectification and filtering of RF.

3-80L4 What is the 6th pair color code in a 25 pair switchboard cable as is found in building telecommunications interconnections?

Red/Blue, Blue/Red.

3-4A6 How might you reduce the inductance of an antenna coil?

Reduce the number of turns.

3-83M2 The GSM (Global System for Mobile Communications) uses what type of CODEC for digital mobile radio system communications?

Regular-Pulse Excited (RPE).

3-2A4 The opposition to the creation of magnetic lines of force in a magnetic circuit is known as:

Reluctance.

3-28C5 An electrical relay is a:

Remotely controlled switching device.

3-12B4 What is the equivalent to the root-mean-square value of an AC voltage?

The DC voltage causing the same heating in a given resistor as the RMS AC voltage of the same value.

3-84M5 Which of the following statements is true?

The Idle Signal (a) (0000111) is used for FEC Phasing Signal 1.

3-78L2 Which of the following answers is true?

The RF Power reading on a CDMA radio is not accurate on an analog power meter.

3-41F5 Which stage of a receiver primarily establishes its noise figure?

The RF stage.

3-75L4 On an analog wattmeter, what part of the scale is most accurate and how much does that accuracy extend to the rest of the reading scale?

The accuracy is only at full scale, and that absolute number reading is carried through to the rest of the range. The upper 1/3 of the meter is the only truly calibrated part.

3-2A1 What determines the strength of the magnetic field around a conductor?

The amount of current.

3-62I6 The output of a separately-excited AC generator running at a constant speed can be controlled by:

The amount of field current.

3-26C4 What conditions exists when a transistor is operating in saturation?

The base-emitter junction and collector-base junction are both forward biased.

3-25C6 What does it mean for a transistor to be fully saturated?

The collector current is at its maximum value.

3-44F2 What is the mixing process in a radio receiver?

The combination of two signals to produce sum and difference frequencies.

3-22C1 In a linear electronic voltage regulator:

The conduction of a control element is varied in direct proportion to the line voltage or load current.

3-49F6 What radio circuit samples analog signals, records and processes them as numbers, then converts them back to analog signals?

The digital signal processing circuit.

3-54G3 What is the resonant frequency in an electrical circuit?

The frequency at which capacitive reactance equals inductive reactance.

3-63J6 What is meant by the term antenna bandwidth?

The frequency range over which an antenna can be expected to perform well.

3-19C2 What is the photoconductive effect?

The increased conductivity of an illuminated semiconductor junction.

3-19C5 What happens to the conductivity of a photosensitive semiconductor junction when it is illuminated?

The junction resistance decreases.

3-5A2 What limits the maximum forward current in a junction diode?

The junction temperature.

3-41F4 What is meant by the term noise figure of a communications receiver?

The level of noise generated in the front end and succeeding stages of a receiver.

3-70K2 What is the frequency range of the marker beacon system used to indicate an aircraft's position during an Instrument Landing System (ILS) approach to an airport's runway?

The outer, the middle, and the inner marker beacon's carrier frequencies are all 75 MHz but the marker beacons are 95% tone-modulated at 400 Hz (outer), 1300 Hz (middle), and 3000 Hz (inner).

3-59H4 Which of the following best describes a pulse modulation system?

The peak transmitter power is normally much greater than the average power.

3-83M4 The International Organization for Standardization has developed a seven-level reference model for a packet-radio communications structure. What level is responsible for the actual transmission of data and handshaking signals?

The physical layer.

3-17B6 Using the polar coordinate system, what visual representation would you get of a voltage in a sinewave circuit?

The plot shows the magnitude and phase angle.

3-57H5 What is meant by the term modulation index?

The ratio between the deviation of a frequency modulated signal and the modulating frequency.

3-2A6 Permeability is defined as:

The ratio of magnetic flux density in a substance to the magnetizing force that produces it.

3-48F6 What is the definition of detection in a radio receiver?

The recovery of intelligence from the modulated RF signal.

3-19C3 What does the photoconductive effect in crystalline solids produce a noticeable change in?

The resistance of the solid.

3-68K2 The Distance Measuring Equipment (DME) measures the distance from the aircraft to the DME ground station. This is referred to as:

The slant range.

3-55G3 In a single-sideband phone signal, what determines the PEP-to-average power ratio?

The speech characteristics.

3-88N6 What determines whether a NAVTEX receiver does not print a particular type of message content?

The subject indicator matches that programmed for rejection by the operator.

3-79L4 The ideal method of removing insulation from wire is:

The thermal stripper.

3-59H5 In a pulse-position modulation system, what parameter does the modulating signal vary?

The time at which each pulse occurs.

3-88N1 What is facsimile?

The transmission of printed pictures for permanent display on paper.

3-66J1 What is the meaning of the term velocity factor of a transmission line?

The velocity of the wave on the transmission line divided by the velocity of light in a vacuum.

3-29D6 What is the relationship between current through a resonant circuit and the voltage across the circuit?

The voltage and current are in phase.

3-95P4 Which of the following statements about the Iridium system is true?

There are 48 spot beams per satellite with a footprint of 30 miles in diameter.

3-26C2 What does it mean for a transistor to be cut off?

There is no current between emitter and collector.

3-100Q1 What device can protect a transmitting station from a direct lightning hit?

There is no device to protect a station from a direct hit from lightning.

3-32D4 In Figure 3D9, determine if there is a problem with this regulated power supply and identify the problem.

There is no problem with the circuit

3-81L1 On a 150 watt marine SSB HF transceiver, what would be indicated by a steady output of 75 watts when keying the transmitter on?

There is probably a defect in the system causing the carrier to be transmitted.

3-89N3 What might occur in NMEA 2000 network topology if one device in line should fail?

There will be no interruption to all other devices.

3-98P4 What best describes the GPS Satellites orbits?

They are in six orbital planes equally spaced and inclined about 55 degrees to the equator.

3-28C2 Why are special precautions necessary in handling FET and CMOS devices?

They are susceptible to damage from static charges.

3-82M5 Which of the following statements about SSB voice transmissions is correct?

They normally use J3E emissions, which consists of one sideband and a suppressed carrier.

3-96P5 Which of the following statements concerning INMARSAT geostationary satellites is true?

They provide coverage to vessels in nearly all of the world's navigable waters.

3-80L3 Why should you not use white or translucent plastic tie wraps on a radio tower?

UV radiation from the Sun deteriorates the plastic very quickly.

3-45F5 What is an undesirable effect of using too wide a filter bandwidth in the IF section of a receiver?

Undesired signals will reach the audio stage.

3-79L2 Which of the following is the preferred method of cleaning solder from plated-through circuit-board holes?

Use a vacuum device.

3-81L4 In a software-defined transceiver, what would be the best way for a technician to make a quick overall evaluation of the radio's operational condition?

Use the built-in self-test feature.

3-43F2 What is the oscillator stage called in a frequency synthesizer?

VCO.

3-24C2 What is a common use of a hot-carrier diode?

VHF and UHF mixers and detectors.

3-68K6 The majority of airborne Distance Measuring Equipment systems automatically tune their transmitter and receiver frequencies to the paired __ / __ channel.

VOR/LOC.

3-24C5 What type of semiconductor diode varies its internal capacitance as the voltage applied to its terminals varies?

Varactor diode.

3-39E1 In a microprocessor-controlled two-way radio, a "watchdog" timer:

Verifies that the microprocessor is executing the program.

3-76L3 What stage determines the maximum frequency response of an oscilloscope?

Vertical amplifier.

3-96P3 What are the directional characteristics of the INMARSAT-C SES antenna?

Very narrow beam width straight-up from the top of the antenna.

3-97P3 What statement best describes the INMARSAT-B services?

Voice at 16 kbps, Fax at 14.4 kbps and high-speed Data at 64/54.

3-97P6 What services are provided by the INMARSAT-M service?

Voice at 6.2 kbps, Data at 2.4 kbps, Fax at 2.4 kbps and e-mail.

3-39E3 Which of the following is not part of a MCU processor?

Voltage Regulator

3-62I3 The expression "voltage regulation" as it applies to a shunt-wound DC generator operating at a constant frequency refers to:

Voltage fluctuations from load to no-load.

3-86N1 What is a common occurrence when voice-testing an SSB aboard a boat?

Voltage panel indicator lamps may glow with each syllable.

3-1A2 What is the basic unit of electrical power?

Watt.

3-79L6 When repairing circuit board assemblies it is most important to:

Wear safety glasses.

3-49F2 What is the purpose of de-emphasis in the receiver audio stage?

When coupled with the transmitter pre-emphasis, flat audio and noise reduction is received.

3-46F6 When would it be more desirable to use an m-derived filter over a constant-k filter?

When you need more attenuation at a certain frequency that is too close to the cut-off frequency for a constant-k filter.