Sea Water Antenna?

One of the items making the rounds on the HamRadioHelpGroup mailing list is this video on the Sea Water Antenna:

At first, I thought, “What a novel idea!” Of course, as the Bible says, there’s nothing new under the sun. PA1AP noted, “Reinventing the wheel I would say. There is prior? art for this and cannot be patented, they should do a little more homework and look around before making such claims… google for ‘Ionic Liquid Antenna’.”

I did just that and found a few interesting references. Apparently, N9ZRT did much of the early work on this type of antenna, and his work is online. In March 2005, some researchers published an academic paper on this topic. Unfortunately, you have to pay for this paper. Another good article can be found on the Highfields (UK) Amateur Radio Club website.

Someone from SPAWAR, the research center that produced the video, replied that in their opinion, this design is unique in that it uses a pump to produce a column of water to form the antenna. This feature makes it patentable. I’m not a patent attorney, but they may have a point here. At any rate, I’m guessing that hams should still feel free to experiment with the antenna.


  1. One of my readers commented in an e-mail:

    With tongue in cheek I offer the new name: Signal Squirter for the liquid antenna. Sorry, just couldn’t pass up the opportunity.

    My reply is that a UHF antenna would then be a “little squirt.”

  2. James T. Lee MD says:

    Interesting situation. It would be a real mess to put one of these in the typical ham’s backyard: big pumping system, huge salt water tank, recirculation pumps, would have to use umbrellas, galoshes, etc.

    I think I will stick to my Delta Loops. HI HI


  3. Jim Lommel says:

    The information on the liquid antenna was very interesting. I do have one quibble however. The author of the paper says that he doesn’t think there is any skin effect with the liquid antenna. I find that extraordinarily unlikely. A conductor is a conductor no matter what it is made of and I don’t have a clue how the EM field could possibly know whether or not the conductor is a liquid, a solid or even a conducting gas. There is certainly nothing in Maxwell’s equations that suggest that. I strongly suspect that the author is correct though when he implies that a liquid antenna is going to have the same radiation pattern as a metal antenna of exactly the same dimensions. What do you think?


  4. The sea water antenna looked pretty original. Once the enclosure was added for? land use it does remind me of a liquid antenna I saw demonstrated at Dayton a few years back. That wasn’t a stream though, it was just filling the tube to various depths.

    Is is a problem to be testing a commercial product using a ham repeater?

  5. kjell-åke says:

    Hello inponerande. Is it to buy? it goes on and what is the price of it.
    73 de sm6vag

    • I don’t think that it’s currently for sale. They are trying to push the technology and sell patents to someone who would make a product out of it.

  6. sea water antenna looks cool to play with but it would be more practical to replace the water with a small lazer

  7. The first though that flashed through my mind was using the oceans as an antenna but that would take a lot of coaxial cable or am I all wet?

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