2016-E2E: Operating methods: operating HF digital modes
Which type of modulation is common for data emissions below 30 MHz?
DTMF tones modulating an FM signal
What do the letters FEC mean as they relate to digital operation?
Forward Error Correction
First Error Correction
Fatal Error Correction
Final Error Correction
How is the timing of JT65 contacts organized?
Alternating transmissions at 1 minute intervals
By exchanging ACK/NAK packets
Stations take turns on alternate days
It depends on the lunar phase
What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?
Selective fading has occurred
One of the signal filters is saturated
The receiver has drifted 5 kHz from the desired receive frequency
The mark and space signal have been inverted
Which type of digital mode does not support keyboard-to-keyboard operation?
What is the most common data rate used for HF packet?
What is the typical bandwidth of a properly modulated MFSK16 signal?
Which of the following HF digital modes can be used to transfer binary files?
Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?
Which of these digital modes has the narrowest bandwidth?
170 Hz shift, 45 baud RTTY
What is the difference between direct FSK and audio FSK?
Direct FSK applies the data signal to the transmitter VFO
Audio FSK has a superior frequency response
Direct FSK uses a DC-coupled data connection
Audio FSK can be performed anywhere in the transmit chain
Which type of control is used by stations using the Automatic Link Enable (ALE) protocol?
ALE can use any type of control
Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful?
All of these choices are correct
Your transmit frequency is incorrect
The protocol version you are using is not the supported by the digital station
Another station you are unable to hear is using the frequency
● = Unseen
● = Weak
● = Review
● = Learned
● = Incorrect answer