Single-sideband voice (SSB)
Voice sent using a narrow, efficient form of AM with the carrier and one half of the signal removed. It's the standard way to talk long distances on shortwave.
What does it sound like?
Clear speech when tuned exactly; slightly off-tune it sounds high-pitched or 'Donald Duck'-like.
Who uses it?
Amateur radio operators, ships and aircraft over oceans, and some military and government stations.
Where and when can I hear it?
Ham bands such as 7.125-7.300 and 14.150-14.350 MHz (US voice segments), and marine and aviation HF channels.
Hear it live
- University of Twente WebSDR (Enschede, the Netherlands) · 14,200 kHz USB
No schedule; 14.125-14.300 MHz is the all-mode (SSB) part of 20 meters in the IARU Region 1 band plan. Tune up and down to find a conversation. - Northern Utah WebSDR #2 (Northern Utah, USA) · 14,290 kHz USB
W1AW's voice bulletin, weekdays at 9:45 p.m. US Eastern time, on 14.290 MHz among other frequencies. W1AW is in Connecticut, so it may be weak or absent at this receiver.
These are free public receivers run by other people; we only link to them. You'll hear the signal only if it's on the air right now and conditions carry it to that receiver, so if it's quiet, try another time. Links last reviewed 2026-09-28.
The science
Single sideband starts with an AM signal and throws away two parts of it: the carrier and one of the two mirror-image sidebands. What remains still holds all of the voice, in a slot about 3 kHz wide, roughly half the width of an AM signal. Because the carrier is missing, the receiver has to supply its own, which is why a slightly mistuned SSB voice sounds high-pitched or low and garbled. By convention hams use the upper sideband on 10 MHz and above.
Why use it?
Every watt goes into the part of the signal that carries speech instead of into a carrier that carries none, so SSB gets much more talk-power out of the same transmitter. Its narrow width lets more stations share a band and lets the receiver admit less noise. Engineers also found it held up better than AM under the fading typical of long-distance shortwave paths.
Lore
John R. Carson of AT&T worked out single sideband mathematically in 1915. The first New York-London radiotelephone circuit, opened in January 1927, used it because transmitter power was limited and efficient antennas at its low frequencies had narrow bandwidths.
Easily confused with
- AM voice, from the same family
- Narrow FM voice, from the same family
- FM broadcast, from the same family