Amateur radio has re-invented its own equipment roughly every twenty years. Each generation looked like a threat to the last one and turned out to be the thing that kept the hobby alive.
Spark, to about 1925
Spark-gap transmitters were simple, loud and hopelessly broad — a single station splattered across everything nearby. They were banned for amateur use as continuous-wave transmitters proved they could do more with far less spectrum. "CW" still means continuous wave, the technology that replaced spark.
Vacuum tubes and the short waves, 1920s–1930s
Regenerative and later superheterodyne receivers, crystal control, and tube transmitters turned worldwide contacts from a stunt into routine work. The transatlantic tests of 1921–23 and the first two-way crossing in November 1923 were done by amateurs pushed onto "worthless" short wavelengths a decade earlier.
Calibration arrived with them: WWV began broadcasting time and frequency standards in 1923, and for decades an amateur checked a crystal or a dial against it. By 1926 Brandon Wentworth, 6OI, had confirmed contact with every continent — the first Worked All Continents, three years after the first two-way crossing of the Atlantic. See DX and awards.
AM to single sideband, 1930s–1960s
Amplitude modulation dominated HF voice for decades. Single sideband — experimented with by amateurs from the 1930s and adopted widely in the 1950s — put all the transmitter power into one sideband and no carrier, roughly quadrupling effective power for the same rig and halving occupied bandwidth. The changeover was bitterly argued at the time. SSB is still the standard HF voice mode; see modulation and modes.
FM, repeaters and the handheld, 1960s–1980s
Surplus commercial FM gear on 2 meters, plus club-built repeaters on hilltops, made reliable local communication ordinary. The handheld transceiver made it portable. This is the era that produced the modern club net, the commute-time ragchew and the local emergency net — see repeaters.
Packet and the first digital wave, 1980s
AX.25 packet radio put error-corrected digital messaging, bulletin boards and mail forwarding on the air before most households had an internet connection. Its descendants are everywhere: APRS for position and telemetry, Winlink for email over radio.
Sound cards and DSP, 1990s
A PC sound card turned every station into a modem. PSK31 made keyboard-to-keyboard conversation practical with a few watts, and digital signal processing brought noise reduction and sharp filtering into ordinary radios.
The decade also closed the commercial chapter of the mode amateurs kept: the last North American coast stations working Morse shut their keys down in July 1999. Ship-to-shore Morse ended; amateur CW did not.
Software-defined radio, 2000s onward
Moving the demodulation into software collapsed the cost of a good receiver and gave every operator a panadapter — a visual display of a whole band at once. A $30 dongle now does what a bench of equipment did in 1995. See receiver performance.
Weak-signal digital, 2017 onward
FT8 and its relatives decode signals well below the noise floor in fixed 15-second slots. The effect on operating has been enormous: worldwide contacts from a compromised antenna in an apartment, through a solar minimum, at 25 watts. Purists argue it is not really a conversation; the counter is that it keeps the bands demonstrably occupied and brings people to the hobby who then learn everything else. See FT8.
What has not changed
Every one of these transitions was resisted, and every one of them was carried out by amateurs experimenting on their own equipment. The next one is probably already running on somebody's bench.
Sources and further reading
- AC6V's amateur radio history — Rod Dinkins, AC6V (SK): a
- NIST time and frequency division — WWV
year-by-year chronology, and the source for the WWV, Worked All Continents and 1999 coast-station dates here.
and WWVH today.
Back to amateur radio history, or read about the people behind it.