Liquid radio — Could temporary jets of seawater be used as functioning radio antennas?Geoff Manaugh - BLDGBLOG11/06/10 4:30pmFiled to: EngineeringRadioSeawaterNavyoceansTechnologyCommunicationsScience23EditPromoteShare to KinjaToggle Conversation toolsGo to permalinkApparently so: as PopSci reports, "communications are vital" for vessels at sea, but deck space for "all the large antennas necessary for long-range (and often encrypted) communications" can be hard to come by.Advertisement"So U.S. Navy R&D lab SPAWAR Systems Center Pacific (SSC Pacific) engineered a clever scheme to turn the ocean's most abundant resource into communications equipment, making antennas out of geysers of seawater."Using arcing vaultworks of oceanwater, like domesticated waves, to beam and receive encrypted telecommunications not only reduces the metal-load of ships-thus also reducing the radar profile of military vessels-it also offers a way to construct "a quick, temporary antenna that could just as easily be dismantled."What they [SPAWAR] came up with is little more than an electromagnetic ring and a water pump. The ring, called a current probe, creates a magnetic field through which the pump shoots a steam of seawater (the salt is a key ingredient, as the tech relies on the magnetic induction properties of sodium chloride). By controlling the height and width of the, the operator can manipulate the frequency at which the antenna transmits and receives. An 80-foot-high stream can transmit and receive anywhere from 2 to 400 mHz, though much smaller streams can be used for varying other frequencies, ranging from HF through VHF to UHF.Turning seawater into a temporary broadcast architecture is absolutely fascinating to me and has some extraordinary design implications for the future. Pirate radio stations made entirely from spiraling pinwheels of saltwater; cell-phone masts disguised as everyday displays spurting seasonally in public parks, from Moscow to Manhattan; TV towers replaced with BusbyBerkeley-like aquatic extravaganzas, camouflaging the electromagnetic infrastructure of the city as a gigantic water garden.Given some salt, for instance, the Trevi Fountain could begin retransmitting mobile phone calls throughout the heat-rippling summer landscape of greater Rome. Ultra-refined specialty saltwaters offer dependable signal clarity in audio HD. La Machine de Marly becomes a buried industrial art project, beaming death metal salt hydrologies to garden visitors: a continuous fountain of thundering music on FM, headbanging to seawater hifi. Espionage conspiracies involving elaborate, deep-cover radio links hidden inside public fountains.I remember reading earlier this year how one of the editors of Gizmodo had accidentally discovered coastal sea caves can act as cell phone signal amplifiers-"I pulled up my camera to take a couple of shots," Gizmodo's Joel Johnson wrote, "when I felt it chirp in my hand. Text message received! I could hear a few other phones around me making noise as well. I don't recall how many bars I had-one or two at the most-but sure enough, the shape of the cave was concentrating the signals from across the water of Santa Barbara enough to restore basic service." But this story takes that to a whole new level of design intervention.