Aboard oceanfaring vessels, real estate is naturally limited. But communications are vital, presenting something of a conundrum for a ship's communications crews: where to place all the large antennas necessary for long-range (and often encrypted) communications. 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.
SSC Pacific (SPAWAR, by the way, is short for Space and Naval Warfare) was looking for a way to reduce the antenna loads on those huge mast arrays you see on most naval warships (the typical vessel has 80 antennae aboard). Aside from the fact that antennas can interfere with each other, piling all that metal that high can increase the ships odds of being picked up on radar. Moreover, not all antennas are needed all the time, so SSC Pacific sought a way to erect a quick, temporary antenna that could just as easily be dismantled.
What they 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.
The Navy sees the technology as potentially replacing its 80-antenna arrays with just ten of the seawater antennas operating at various frequencies to cover the entire spectrum currently served. And with a tested range of 30 miles, the antennas can go the distance as well. Outside of military use, the antennas could serve as compact emergency antennas for civilian watercraft, communication systems on offshore oil rigs, or on land using saltwater streams enclosed in tubes.
What if there were strong winds that blew the stream off course? I mean this sounds nifty and all but an 80 foot high stream and even a decent breeze that thing is gonna move
Seems to me that this is just a whip antenna, it is not directorial and has low gain. You can replace the salt water fountain with a piece of wire the same and produce the same or better results this would cost as much as a piece of wire. I can only see this being practical for use in really low frequency communications where antennas need to be several hundred feet tall.
yeah it definitely could HeLp reduce the antenna load, but not by any means replace it.. it's just another thing to fail/go wrong at the worst possible time.
cool tech tho, could be implemented in lots of other ways & for many other people besides the Navy ;)
Using the hull of the ship as an antenna could be better.
Also there are fractal antennas today that can communicate in many different frequency bands. So one of them could replace multiple antennas on a ship.
Likewise, such water-jets might be illuminated, with a columnated beam or laser(s) or LED(s) ... IR ... etc., in order to effect optical communications broadcasting, over the horizon. (handy in a jammed/cluttered E/M environment).
Any chance of using them for X-Band and/or S-Band Illumination? ... For CIDS/Anti-Cruise sensor fences?
What happens when you soak your phone or radio with the water? There are too many possible problems for that to be a viable option.
This is pretty cool, except what happens when it's very windy, or it's raining? Does it still work in those conditions?
read the last part of the last sentence, you guys talking about wind are retarded.
Outside of military use, the antennas could serve as compact emergency antennas for civilian watercraft, communication systems on offshore oil rigs, or on land using saltwater streams enclosed in tubes.
@ Buzz: As others were saying, weather becomes a real factor. Winter could have you throwing a broken up ice stream. Then there's lightning. I wonder if adding salt might make a significant difference, or maybe blending a custom salt. Then adding some level of pulverized metal particles and using a larger coil. This is interesting, but I just haven't studied enough chemistry to know what would be optimal for blending in an application like this. Maybe iridium. I know it shows a little tiny stream in the pic, but you'd think that to be dependable it would have to be quite a bit more robust. Now with it being water, you could throw it from one point on the ship to another, or go dipole, or cross streams...("Ray, I thought you said crossing the streams was bad...Ray?") For some reason, this degausser I made by hand years ago to degauss my mom's tv keeps coming to mind, but I don't know why. Maybe I should be thinking ions....