G8 – SIGNALS AND EMISSIONS [3 Exam Questions – 3 Groups] Flashcards
How is an FSK signal generated?
A. By keying an FM transmitter with a sub-audible tone
B. By changing an oscillator’s frequency directly with a digital control signal
C. By using a transceiver’s computer data interface protocol to change frequencies
D. By reconfiguring the CW keying input to act as a tone generator
G8A01 (B)
B. By changing an oscillator’s frequency directly with a digital control signal
What is the name of the process that changes the phase angle of an RF signal to convey information?
A. Phase convolution
B. Phase modulation
C. Phase transformation
D. Phase inversion
G8A02 (B)
B. Phase modulation
What is the name of the process that changes the instantaneous frequency of an RF wave to convey information?
A. Frequency convolution
B. Frequency transformation
C. Frequency conversion
D. Frequency modulation
G8A03 (D)
D. Frequency modulation
What emission is produced by a reactance modulator connected to a transmitter RF amplifier stage?
A. Multiplex modulation
B. Phase modulation
C. Amplitude modulation
D. Pulse modulation
G8A04 (B)
B. Phase modulation
What type of modulation varies the instantaneous power level of the RF signal?
A. Frequency shift keying
B. Phase modulation
C. Frequency modulation
D. Amplitude modulation
G8A05 (D)
D. Amplitude modulation
Which of the following is characteristic of QPSK31?
A. It is sideband sensitive
B. It has forward error correction
C. The bandwidth is slightly higher than BPSK31
D. All these choices are correct
G8A06 (C)
C. The bandwidth is slightly higher than BPSK31
Which of the following phone emissions uses the narrowest bandwidth?
A. Single sideband
B. Double sideband
C. Phase modulation
D. Frequency modulation
G8A07 (A)
A. Single sideband
Which of the following is an effect of overmodulation?
A. Insufficient audio
B. Insufficient bandwidth
C. Frequency drift
D. Excessive bandwidth
G8A08 (D)
D. Excessive bandwidth
What type of modulation is used by the FT8 digital mode?
A. 8-tone frequency shift keying
B. Vestigial sideband
C. Amplitude compressed AM
D. Direct sequence spread spectrum
G8A09 (A)
A. 8-tone frequency shift keying
What is meant by the term “flat-topping,” when referring to a single sideband phone transmission?
A. Signal distortion caused by insufficient collector current
B. The transmitter’s automatic level control (ALC) is properly adjusted
C. Signal distortion caused by excessive drive
D. The transmitter’s carrier is properly suppressed
G8A10 (C)
C. Signal distortion caused by excessive drive
What is the modulation envelope of an AM signal?
A. The waveform created by connecting the peak values of the modulated signal
B. The carrier frequency that contains the signal
C. Spurious signals that envelop nearby frequencies
D. The bandwidth of the modulated signal
G8A11 (A)
A. The waveform created by connecting the peak values of the modulated signal
Which of the following narrow-band digital modes can receive signals with very low signal-to-noise ratios?
A. MSK144
B. FT8
C. AMTOR
D. MFSK32
G8A12 (B)
B. FT8
Which mixer input is varied or tuned to convert signals of different frequencies to an intermediate frequency (IF)?
A. Image frequency
B. Local oscillator
C. RF input
D. Beat frequency oscillator
G8B01 (B)
B. Local oscillator
If a receiver mixes a 13.800 MHz VFO with a 14.255 MHz received signal to produce a 455 kHz intermediate frequency (IF) signal, what type of interference will a 13.345 MHz signal produce in the receiver?
A. Quadrature noise
B. Image response
C. Mixer interference
D. Intermediate interference
G8B02 (B)
B. Image response
What is another term for the mixing of two RF signals?
A. Heterodyning
B. Synthesizing
C. Cancellation
D. Phase inverting
G8B03 (A)
A. Heterodyning
What is the stage in a VHF FM transmitter that generates a harmonic of a lower frequency signal to reach the desired operating frequency?
A. Mixer
B. Reactance modulator
C. Pre-emphasis network
D. Multiplier
G8B04 (D)
D. Multiplier
What is the approximate bandwidth of a PACTOR-III signal at maximum data rate?
A. 31.5 Hz
B. 500 Hz
C. 1800 Hz
D. 2300 Hz
G8B05 (D)
D. 2300 Hz
What is the total bandwidth of an FM phone transmission having 5 kHz deviation and 3 kHz modulating frequency?
A. 3 kHz
B. 5 kHz
C. 8 kHz
D. 16 kHz
G8B06 (D)
D. 16 kHz
What is the frequency deviation for a 12.21 MHz reactance modulated oscillator in a 5 kHz deviation, 146.52 MHz FM phone transmitter?
A. 101.75 Hz
B. 416.7 Hz
C. 5 kHz
D. 60 kHz
G8B07 (B)
B. 416.7 Hz
Why is it important to know the duty cycle of the mode you are using when transmitting?
A. To aid in tuning your transmitter
B. Some modes have high duty cycles that could exceed the transmitter’s average power rating
C. To allow time for the other station to break in during a transmission
D. The attenuator will have to be adjusted accordingly
G8B08 (B)
B. Some modes have high duty cycles that could exceed the transmitter’s average power rating
Why is it good to match receiver bandwidth to the bandwidth of the operating mode?
A. It is required by FCC rules
B. It minimizes power consumption in the receiver
C. It improves impedance matching of the antenna
D. It results in the best signal-to-noise ratio
G8B09 (D)
D. It results in the best signal-to-noise ratio
What is the relationship between transmitted symbol rate and bandwidth?
A. Symbol rate and bandwidth are not related
B. Higher symbol rates require wider bandwidth
C. Lower symbol rates require wider bandwidth
D. Bandwidth is always half the symbol rate
G8B10 (B)
B. Higher symbol rates require wider bandwidth
What combination of a mixer’s Local Oscillator (LO) and RF input frequencies is found in the output?
A. The ratio
B. The average
C. The sum and difference
D. The arithmetic product
G8B11 (C)
C. The sum and difference
What process combines two signals in a non-linear circuit or connection to produce unwanted spurious outputs?
A. Intermodulation
B. Heterodyning
C. Detection
D. Rolloff
G8B12 (A)
A. Intermodulation
On what band do amateurs share channels with the unlicensed Wi-Fi service?
A. 432 MHz
B. 902 MHz
C. 2.4 GHz
D. 10.7 GHz
G8C01 (C)
C. 2.4 GHz
Which digital mode is used as a low-power beacon for assessing HF propagation?
A. WSPR
B. Olivia
C. PSK31
D. SSB-SC
G8C02 (A)
A. WSPR
What part of a packet radio frame contains the routing and handling information?
A. Directory
B. Preamble
C. Header
D. Footer
G8C03 (C)
C. Header
Which of the following describes Baudot code?
A. A 7-bit code with start, stop, and parity bits
B. A code using error detection and correction
C. A 5-bit code with additional start and stop bits
D. A code using SELCAL and LISTEN
G8C04 (C)
C. A 5-bit code with additional start and stop bits
In the PACTOR protocol, what is meant by an NAK response to a transmitted packet?
A. The receiver is requesting the packet be retransmitted
B. The receiver is reporting the packet was received without error
C. The receiver is busy decoding the packet
D. The entire file has been received correctly
G8C05 (A)
A. The receiver is requesting the packet be retransmitted
What action results from a failure to exchange information due to excessive transmission attempts when using PACTOR or WINMOR?
A. The checksum overflows
B. The connection is dropped
C. Packets will be routed incorrectly
D. Encoding reverts to the default character set
G8C06 (B)
B. The connection is dropped
How does the receiving station respond to an ARQ data mode packet containing errors?
A. It terminates the contact
B. It requests the packet be retransmitted
C. It sends the packet back to the transmitting station
D. It requests a change in transmitting protocol
G8C07 (B)
B. It requests the packet be retransmitted
Which of the following statements is true about PSK31?
A. Upper case letters are sent with more power
B. Upper case letters use longer Varicode symbols and thus slow down transmission
C. Error correction is used to ensure accurate message reception
D. Higher power is needed as compared to RTTY for similar error rates
G8C08 (B)
B. Upper case letters use longer Varicode symbols and thus slow down transmission
What does the number 31 represent in “PSK31”?
A. The approximate transmitted symbol rate
B. The version of the PSK protocol
C. The year in which PSK31 was invented
D. The number of characters that can be represented by PSK31
G8C09 (A)
A. The approximate transmitted symbol rate
How does forward error correction (FEC) allow the receiver to correct errors in received data packets?
A. By controlling transmitter output power for optimum signal strength
B. By using the Varicode character set
C. By transmitting redundant information with the data
D. By using a parity bit with each character
G8C10 (C)
C. By transmitting redundant information with the data
How are the two separate frequencies of a Frequency Shift Keyed (FSK) signal identified?
A. Dot and dash
B. On and off
C. High and low
D. Mark and space
G8C11 (D)
D. Mark and space
Which type of code is used for sending characters in a PSK31 signal?
A. Varicode
B. Viterbi
C. Volumetric
D. Binary
G8C12 (A)
A. Varicode
What is indicated on a waterfall display by one or more vertical lines on either side of a digital signal?
A. Long path propagation
B. Backscatter propagation
C. Insufficient modulation
D. Overmodulation
G8C13 (D)
D. Overmodulation
Which of the following describes a waterfall display?
A. Frequency is horizontal, signal strength is vertical, time is intensity
B. Frequency is vertical, signal strength is intensity, time is horizontal
C. Frequency is horizontal, signal strength is intensity, time is vertical
D. Frequency is vertical, signal strength is horizontal, time is intensity
G8C14 (C)
C. Frequency is horizontal, signal strength is intensity, time is vertical
