Digital Modes and Data Communications Flashcards
7 cards from real Ham Radio General Class Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Digital Modes and Data Communications flashcards as text
What is DMR in the context of amateur radio communication?
Answer: A Time Division Multiple Access digital voice mode used on VHF and UHF
DMR (Digital Mobile Radio) uses TDMA technology to allow two simultaneous conversations on a single 12.5 kHz channel and has been widely adopted by amateur operators on VHF/UHF.
What is Varicode, as used by PSK31?
Answer: A variable-length character encoding that assigns shorter codes to more frequently used characters
Varicode is a variable-length encoding where common characters like 'e' and 't' use fewer bits than rare characters, improving throughput efficiency for typical English text in PSK31.
With which digital communication system is D-STAR primarily associated?
Answer: Digital voice and data linked through repeater networks and the internet
D-STAR (Digital Smart Technologies for Amateur Radio) is a digital radio system supporting voice, slow-speed data, and high-speed data with worldwide internet linking through repeaters.
What is the standard baud rate used for Baudot RTTY on HF amateur radio bands?
Answer: 45.45 baud
HF RTTY using the Baudot code operates at 45.45 baud, a rate derived from early commercial teleprinter equipment that became the amateur HF RTTY standard.
Which of the following best describes the FT4 digital mode?
Answer: A faster variant of FT8 using 7.5-second cycles designed for contest operation
FT4 uses 7.5-second transmission cycles — half of FT8's 15 seconds — and was specifically developed to handle higher QSO rates in amateur radio contest environments.
What is the primary advantage of digital modes such as FT8 over SSB voice for weak-signal communication?
Answer: Digital modes can successfully decode signals 15 dB or more below the audible noise floor
FT8 and similar modes use coherent detection and structured error correction to decode signals far below what the human ear can perceive, enabling reliable contacts at extreme distances with low power.
What emission type designator applies to RTTY that uses direct frequency shift keying of the carrier?
Answer: F1B
F1B is the ITU emission designator for a frequency-modulated carrier (F) with a single digital channel (1) carrying telegraphy (B), which precisely describes direct FSK RTTY.