114 lines
3.9 KiB
Markdown
114 lines
3.9 KiB
Markdown
G8C – Digital emission modes
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- [[G8C01]] (C)
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On what band do amateurs share channels with the unlicensed Wi-Fi service?
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- A. 432 MHz
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- B. 902 MHz
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- C. 2.4 GHz
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- D. 10.7 GHz
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--
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- [[G8C02]] (A)
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Which digital mode is used as a low-power beacon for assessing HF propagation?
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- A. WSPR
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- B. MFSK16
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- C. PSK31
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- D. SSB-SC
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--
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- [[G8C03]] (C)
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What part of a packet radio frame contains the routing and handling information?
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- A. Directory
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- B. Preamble
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- C. Header
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- D. Trailer
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--
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- [[G8C04]] (C)
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Which of the following describes Baudot code?
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- A. A 7-bit code with start, stop, and parity bits
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- B. A code using error detection and correction
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- C. A 5-bit code with additional start and stop bits
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- D. A code using SELCAL and LISTEN
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--
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- [[G8C05]] (A)
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In an ARQ mode, what is meant by a NAK response to a transmitted packet?
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- A. Request retransmission of the packet
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- B. Packet was received without error
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- C. Receiving station connected and ready for transmissions
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- D. Entire file received correctly
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--
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- [[G8C06]] (B)
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What action results from a failure to exchange information due to excessive transmission attempts when using an ARQ mode?
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- A. The checksum overflows
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- B. The connection is dropped
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- C. Packets will be routed incorrectly
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- D. Encoding reverts to the default character set
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--
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- [[G8C07]] (B)
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Which of the following narrow-band digital modes can receive signals with very low signal-to-noise ratios?
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- A. MSK144
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- B. FT8
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- C. AMTOR
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- D. MFSK32
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--
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- [[G8C08]] (B)
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Which of the following statements is true about PSK31?
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- A. Upper case letters are sent with more power
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- B. Upper case letters use longer Varicode bit sequences and thus slow down transmission
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- C. Error correction is used to ensure accurate message reception
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- D. Higher power is needed as compared to RTTY for similar error rates
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- [[G8C09]] (B)
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Which is true of mesh network microwave nodes?
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- A. Having more nodes increases signal strengths
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- B. If one node fails, a packet may still reach its target station via an alternate node
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- C. Links between two nodes in a network may have different frequencies and bandwidths
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- D. More nodes reduce overall microwave out of band interference
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- [[G8C10]] (C)
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How does forward error correction (FEC) allow the receiver to correct data errors?
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- A. By controlling transmitter output power for optimum signal strength
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- B. By using the Varicode character set
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- C. By transmitting redundant information with the data
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- D. By using a parity bit with each character
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--
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- [[G8C11]] (D)
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How are the two separate frequencies of a Frequency Shift Keyed (FSK) signal identified?
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- A. Dot and dash
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- B. On and off
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- C. High and low
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- D. Mark and space
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- [[G8C12]] (A)
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Which type of code is used for sending characters in a PSK31 signal?
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- A. Varicode
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- B. Viterbi
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- C. Volumetric
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- D. Binary
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- [[G8C13]] (D)
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What is indicated on a waterfall display by one or more vertical lines on either side of a data mode or RTTY signal?
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- A. Long path propagation
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- B. Backscatter propagation
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- C. Insufficient modulation
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- D. Overmodulation
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- [[G8C14]] (C)
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Which of the following describes a waterfall display?
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- A. Frequency is horizontal, signal strength is vertical, time is intensity
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- B. Frequency is vertical, signal strength is intensity, time is horizontal
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- C. Frequency is horizontal, signal strength is intensity, time is vertical
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- D. Frequency is vertical, signal strength is horizontal, time is intensity
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- [[G8C15]] (C)
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What does an FT8 signal report of +3 mean?
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- A. The signal is 3 times the noise level of an equivalent SSB signal
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- B. The signal is S3 (weak signals)
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- C. The signal-to-noise ratio is equivalent to +3dB in a 2.5 kHz bandwidth
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- D. The signal is 3 dB over S9
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--
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- [[G8C16]] (D)
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Which of the following provide digital voice modes?
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- A. WSPR, MFSK16, and EasyPAL
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- B. FT8, FT4, and FST4
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- C. Winlink, PACTOR II, and PACTOR III
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- D. DMR, D-STAR, and SystemFusion
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