Which digital mode is used as a low-power beacon for assessing HF propagation?

1. A WSPR
2. B MFSK16
3. C PSK31
4. D SSB-SC

What part of a packet radio frame contains the routing and handling information?

1. A Directory
2. B Preamble
3. C Header
4. D Trailer

Which of the following describes Baudot code?

1. A A 7-bit code with start, stop, and parity bits
2. B A code using error detection and correction
3. C A 5-bit code with additional start and stop bits
4. D A code using SELCAL and LISTEN

In an ARQ mode, what is meant by a NAK response to a transmitted packet?

1. A Request retransmission of the packet
2. B Packet was received without error
3. C Receiving station connected and ready for transmissions
4. D Entire file received correctly

What action results from a failure to exchange information due to excessive transmission attempts when using an ARQ mode?

1. A The checksum overflows
2. B The connection is dropped
3. C Packets will be routed incorrectly
4. D Encoding reverts to the default character set

Which of the following narrow-band digital modes can receive signals with very low signal-to-noise ratios?

1. A MSK144
2. B FT8
3. C AMTOR
4. D MFSK32

Which of the following statements is true about PSK31?

1. A Upper case letters are sent with more power
2. B Upper case letters use longer Varicode bit sequences and thus slow down transmission
3. C Error correction is used to ensure accurate message reception
4. D Higher power is needed as compared to RTTY for similar error rates

Which is true of mesh network microwave nodes?

1. A Having more nodes increases signal strengths
2. B If one node fails, a packet may still reach its target station via an alternate node
3. C Links between two nodes in a network may have different frequencies and bandwidths
4. D More nodes reduce overall microwave out of band interference

How does forward error correction (FEC) allow the receiver to correct data errors?

1. A By controlling transmitter output power for optimum signal strength
2. B By using the Varicode character set
3. C By transmitting redundant information with the data
4. D By using a parity bit with each character

How are the two separate frequencies of a Frequency Shift Keyed (FSK) signal identified?

1. A Dot and dash
2. B On and off
3. C High and low
4. D Mark and space

Which type of code is used for sending characters in a PSK31 signal?

1. A Varicode
2. B Viterbi
3. C Volumetric
4. D Binary

What is indicated on a waterfall display by one or more vertical lines on either side of a data mode or RTTY signal?

1. A Long path propagation
2. B Backscatter propagation
3. C Insufficient modulation
4. D Overmodulation

Which of the following describes a waterfall display?

1. A Frequency is horizontal, signal strength is vertical, time is intensity
2. B Frequency is vertical, signal strength is intensity, time is horizontal
3. C Frequency is horizontal, signal strength is intensity, time is vertical
4. D Frequency is vertical, signal strength is horizontal, time is intensity

What does an FT8 signal report of +3 mean?

1. A The signal is 3 times the noise level of an equivalent SSB signal
2. B The signal is S3 (weak signals)
3. C The signal-to-noise ratio is equivalent to +3dB in a 2.5 kHz bandwidth
4. D The signal is 3 dB over S9

Which of the following provide digital voice modes?

1. A WSPR, MFSK16, and EasyPAL
2. B FT8, FT4, and FST4
3. C Winlink, PACTOR II, and PACTOR III
4. D DMR, D-STAR, and SystemFusion