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?
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.
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?
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 12.6 volt winding. (0% chose this)
The 150 volt winding. (0% chose this)
The 5.0 volt winding. (0% chose this)
All will have equal resistance values. (0% chose this)
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?
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?
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?
Local oscillator interference. (0% chose this)
An image response. (0% chose this)
Mixer interference. (0% chose this)
Intermediate frequency interference. (0% chose this)
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?
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?
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?
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:
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?
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?
The Distance Measuring Equipment (DME) ground station has a built-in delay between reception of an interrogation and transmission of the reply to allow:
Someone to answer the call. (0% chose this)
The VOR to make a mechanical hook-up. (0% chose this)
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?
The majority of airborne Distance Measuring Equipment systems automatically tune their transmitter and receiver frequencies to the paired __ / __ channel.
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.
What is the main underlying operating principle of the Very-high-frequency Omnidirectional Range (VOR) aircraft navigational system?
A definite amount of time is required to send and receive a radio signal. (0% chose this)
The difference between the peak values of two DC voltages may be used to determine an aircraft’s altitude above a selected VOR station. (0% chose this)
A phase difference between two AC voltages may be used to determine an aircraft’s azimuth position in relation to a selected VOR station. (0% chose this)
A phase difference between two AC voltages may be used to determine an aircraft’s distance from a selected VOR station. (0% chose this)
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?
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, middle, and inner marker beacons’ UHF frequencies are unique for each ILS equipped airport to provide unambiguous frequency-protected reception areas in the 329.15 to 335.00 MHz range. (0% chose this)
The outer marker beacon’s carrier frequency is 400 MHz, the middle marker beacon’s carrier frequency is 1300 MHz, and the inner marker beacon’s carrier frequency is 3000 MHz. (0% chose this)
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). (0% chose this)
The outer, marker beacon’s carrier frequency is 3000 kHz, the middle marker beacon’s carrier frequency is 1300 kHz, and the inner marker beacon’s carrier frequency is 400 kHz. (0% chose this)
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:
Operates within the assigned frequency range of 108.10 to 111.95 GHz. (0% chose this)
Produces two amplitude modulated antenna patterns; one pattern above and one pattern below the normal 2.5 degree approach glide path of the aircraft. (0% chose this)
Frequencies are automatically tuned-in when the proper glide slope frequency is selected on the aircraft’s Navigation and Communication (NAV/COMM) transceiver. (0% chose this)
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. (0% chose this)
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:
All Non Directional Beacon (NDB) transmitters are turned-off at dusk and turned-on at dawn. (0% chose this)
Non Directional Beacon (NDB) transmissions can bounce-off the Earth’s ionosphere at night and be received at almost any direction. (0% chose this)
An aircraft’s ADF transmissions will be slowed at night due to the increased density of the Earth’s atmosphere after sunset. (0% chose this)
An aircraft’s ADF antennas usually collect dew moisture after sunset which decreases their effective reception distance from an NDB transmitter. (0% chose this)
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)?
Choose the only correct statement about an aircraft’s Automatic Direction Finding (ADF) equipment.
An aircraft’s ADF transmission exhibits primarily a line-of-sight range to the ground-based target station and will not follow the curvature of the Earth. (0% chose this)
Only a single omnidirectional sense antenna is required to receive an NDB transmission and process the signal to calculate the aircraft’s bearing to the selected ground station. (0% chose this)
All frequencies in the ADF’s operating range except the commercial standard broadcast stations (550 to 1660 kHz) can be utilized as a navigational Non Directional Beacon (NDB) signal. (0% chose this)
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. (0% chose this)
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 electronically steerable phased-array directional antenna. (0% chose this)
An L-band monopole blade-type omnidirectional antenna. (0% chose this)
A folded dipole reception antenna. (0% chose this)
An internally mounted, mechanically rotatable loop antenna. (0% chose this)
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?
400 Hz power supplies draw less current than 60 Hz supplies allowing more current available for other systems on the aircraft. (0% chose this)
A 400 Hz power supply generates less heat and operates much more efficiently than a 60 Hz power supply. (0% chose this)
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. (0% chose this)
400 Hz power supplies are much less expensive to produce than power supplies with lower line frequencies. (0% chose this)
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.
To provide reference points on an analog receiver dial thereby aiding in the alignment of the receiver. (0% chose this)
To heterodyne the frequency being measured with a known variable frequency oscillator until zero beat is achieved, thereby indicating the unknown frequency. (0% chose this)
To measure the deviation in an FM transmitter in order to determine the percentage of modulation. (0% chose this)
To measure the time between events, or the frequency, which is the reciprocal of the time. (0% chose this)
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. (0% chose this)
The accuracy is constant throughout the entire range of the meter. (0% chose this)
The accuracy is only there at the upper 5% of the meter, and is not carried through at any other reading. (0% chose this)
The accuracy cannot be determined at any reading. (0% chose this)
How does a spectrum analyzer differ from a conventional oscilloscope?
The oscilloscope is used to display electrical signals while the spectrum analyzer is used to measure ionospheric reflection. (0% chose this)
The oscilloscope is used to display electrical signals in the frequency domain while the spectrum analyzer is used to display electrical signals in the time domain. (0% chose this)
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. (0% chose this)
The oscilloscope is used for displaying audio frequencies and the spectrum analyzer is used for displaying radio frequencies. (0% chose this)
A(n) ____ and ____ can be combined to measure the characteristics of transmission lines. Such an arrangement is known as a time-domain reflectometer (TDR).
Frequency spectrum analyzer, RF generator. (0% chose this)
Oscilloscope, pulse generator. (0% chose this)
AC millivolt meter, AF generator. (0% chose this)
Frequency counter, linear detector. (0% chose this)
What instrument is commonly used by radio service technicians to monitor frequency, modulation, check receiver sensitivity, distortion, and to generate audio tones?
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?
Replace the tachometer of the elevator. (0% chose this)
Add a .01 µF capacitor across the motor/tachometer leads. (0% chose this)
Add a 200 µF capacity across the motor/tachometer leads. (0% chose this)
Add an isolating resistor in series with the motor leads. (0% chose this)
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. (0% chose this)
Direct sequence. (0% chose this)
Time-domain frequency modulation. (0% chose this)
Frequency compandored spread spectrum. (0% chose this)
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. (0% chose this)
The coded signal identifies the nature of the distress situation. (0% chose this)
The coded signal only identifies the vessel’s name and port of registry. (0% chose this)
If the GMDSS Radio Operator does not program the EPIRB, it will transmit default information such as the follow-on communications frequency and mode. (0% chose this)
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?
Which of the following conditions can render INMARSAT -B communications impossible?
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. (0% chose this)
A satellite whose signal is on a low elevation, below the horizon. (0% chose this)
Travel beyond the effective radius of the satellite. (0% chose this)
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. (0% chose this)
INMARSAT-B antennas are bulkier but omni-directional, while INMARSAT-C antennas are smaller and parabolic, for aiming at the satellite. (0% chose this)
INMARSAT-B antennas are parabolic and smaller for higher gain, while INMARSAT-C antennas are larger but omni-directional. (0% chose this)
INMARSAT-C antennas are smaller but omni-directional, while INMARSAT-B antennas are parabolic for lower gain. (0% chose this)
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.
Sites having multiple transmitting antennas must include antennas with more than _______% of the maximum permissible power density exposure limit when evaluating RF site exposure.