Cold-hearted is the sailor who doesn’t daydream of slipping the lines and setting sail to parts unknown. Troubles arise for many of us, however, when we try reconciling this dream with the connectivity demands of modern-day living, not to mention the desire for weather information while at sea and the ability to reach out in case of an emergency.
True, satellite-communication options exist for the bluewater sailor — at a price — but some prefer instead to rely on technology that’s been in use for the better part of the past century: high-frequency radio communication.
Once thought of as a hard-to-master black art, communicating by single-sideband radio is greatly simplified these days, thanks to improved antennas and digital signal processing that takes much of the guesswork out of frequency selection, which is key to successful radio transmissions. Add a Pactor modem to the mix and your radio becomes a data hub capable of sending and receiving email and weather forecasts anywhere on the globe.
In 1915, John Renshaw Carson applied for the first U.S. patent for single-sideband modulation, a technology that dramatically increases the efficiency of a radio’s amplifier by only broadcasting one half, or the sideband, of a traditional AM radio signal. AM radios, by contrast, combine a specific radio frequency (the carrier wave) with a broadcast signal that includes the message or data being communicated. By broadcasting only the sideband portion of the signal, SSB radios are able to use their amplification power more efficiently, and they can harness the phenomenon of so-called skip, or sky wave, propagation, where radio waves are reflected or refracted between Earth’s electrically charged ionosphere and the ground to deliver significantly longer-range transmissions than an AM radio or the line-of-sight VHF radios often found on sailboats.