Ham Radio General Class Test Digital Modes and Data Communications

Question 1

Which digital mode uses 15-second structured time slots and is most widely used for weak-signal HF communication?

Accepted Answer

FT8

Answer

FT8 uses 15-second transmission and receive windows and can decode signals well below the audible noise floor, making it the dominant weak-signal HF mode.

Question 2

What is the standard frequency shift used for RTTY operation on HF bands?

Accepted Answer

170 Hz

Answer

The standard frequency shift for HF RTTY is 170 Hz between the mark and space frequencies, which fits within the passband of an SSB transceiver.

Question 3

What is the approximate bandwidth occupied by a PSK31 signal?

Accepted Answer

31 Hz

Answer

PSK31 uses a symbol rate of 31.25 baud, resulting in a signal bandwidth of approximately 31 Hz — extremely narrow for HF digital communication.

Question 4

At what standard data rate is packet radio typically operated on HF bands?

Accepted Answer

300 baud

Answer

HF packet radio is standardized at 300 baud due to the narrower bandwidth constraints and propagation characteristics of HF frequencies.

Question 5

What does APRS stand for?

Accepted Answer

Automatic Packet Reporting System

Answer

APRS stands for Automatic Packet Reporting System, used to automatically transmit position, weather, and status information over amateur radio.

Ham Radio General Class Test Practice Test

Ham Radio General Class Test Practice Test

Ham Radio General Class Test Digital Modes and Data Communications