Digital Communications
Explore the exciting world of digital modes in amateur radio, from classic RTTY to modern FT8.
Overview
A great number of exciting new digital operating modes have developed, largely because of the availability of personal computers, soundcards, and advanced software. But amateur digital communication began in earnest in the late 1940's (if you don't count Morse as a digital mode!) when hams worked out techniques of connecting mechanical Teletype keyboard/printers to amateur gear using FSK and AFSK modulation. There are too many different modes to list individually, but here are some of the major ones:
FT8
In 2018 it became by far the most popular digital mode for award chasing and working DX. The WSJT-X software can be downloaded from Joe Taylor's web site.
Packet
One of the first "modern" digital modes, packet radio transmits data in groups or "packets" of 10s or 100s of bytes. Transmission speeds typically range from 300 bps on HF to 1200 and 9600 bps on VHF/UHF.
PSK31
Probably the most popular keyboard to keyboard digital mode, PSK31 is normally generated and decoded using PC soundcards. It occupies very small bandwidths (~100 Hz) and offers effective communication at low power.
RTTY
Radio teletype is the original keyboard to keyboard mode, based on the 5-bit Baudot code. It uses 170 Hz frequency shift keying at a 45.45 baud rate — 60 words per minute.
Winlink
A worldwide radio email system that allows licensed amateur radio operators to send and receive email over radio frequencies without internet access. Ideal for emergency communications and remote operations.
DMR, Fusion, D-Star
Digital voice modes that provide clear audio, text messaging, and worldwide connectivity through internet-linked repeaters. DMR uses TDMA technology, Fusion offers analog/digital flexibility, and D-Star pioneered amateur digital voice.
Slow & Fast Scan TV
SSTV transmits still images over narrow bandwidth HF frequencies, while ATV (Amateur Television) broadcasts full-motion video on UHF/microwave bands. Both modes allow hams to share visual content over the air.
Other Modes
Many other data modes are available including Pactor, Clover, MFSK, Olivia, Throb, DominoEX, MT63, Thor, and AMTOR which provides error detection and correction.