Which of the following types of modulation is used for data emissions below 30 MHz?

1. A DTMF tones modulating an FM signal
2. B FSK
3. C Pulse modulation
4. D Spread spectrum

Which of the following synchronizes WSJT-X digital mode transmit/receive timing?

1. A Alignment of frequency shifts
2. B Synchronization of computer clocks
3. C Sync-field transmission
4. D Sync-pulse timing

To what does the "4" in FT4 refer?

1. A Multiples of 4 bits of user information
2. B Four-tone continuous-phase frequency shift keying
3. C Four transmit/receive cycles per minute
4. D All these choices are correct

Which of the following is characteristic of the FST4 mode?

1. A Four-tone Gaussian frequency shift keying
2. B Variable transmit/receive periods
3. C Seven different tone spacings
4. D All these choices are correct

Which of these digital modes does not support keyboard-to-keyboard operation?

1. A WSPR
2. B RTTY
3. C PSK31
4. D MFSK16

What is the length of an FT8 transmission cycle?

1. A It varies with the amount of data
2. B 8 seconds
3. C 15 seconds
4. D 30 seconds

How does Q65 differ from JT65?

1. A Keyboard-to keyboard operation is supported
2. B Quadrature modulation is used
3. C Multiple receive cycles are averaged
4. D All these choices are correct

Which of the following HF digital modes can be used to transfer binary files?

1. A PSK31
2. B PACTOR
3. C RTTY
4. D AMTOR

Which of the following HF digital modes uses variable-length character coding?

1. A RTTY
2. B PACTOR
3. C MT63
4. D PSK31

Which of these digital modes has the narrowest bandwidth?

1. A MFSK16
2. B 170 Hz shift, 45-baud RTTY
3. C FT8
4. D PACTOR IV

What is the difference between direct FSK and audio FSK?

1. A Direct FSK modulates the transmitter VFO
2. B Direct FSK occupies less bandwidth
3. C Direct FSK can transmit higher baud rates
4. D All these choices are correct

How do ALE stations establish contact?

1. A ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received
2. B ALE radios monitor an internet site for the frequency they are being paged on
3. C ALE radios send a constant tone code to establish a frequency for future use
4. D ALE radios activate when they hear their signal echoed by back scatter

Which of these digital modes has the highest data throughput under clear communication conditions?

1. A MFSK16
2. B 170 Hz shift, 45 baud RTTY
3. C FT8
4. D PACTOR IV