Hello,

We noticed you're browsing in private or incognito mode.

To continue reading this article, please exit incognito mode or log in.

Not a subscriber? Subscribe now for unlimited access to online articles.

John Pavlus

A View from John Pavlus

Navy Antenna Using Seawater instead of Metal

The Electrolytic Fluid Antenna has a range of 30 miles and could be used on sea or land.

  • November 18, 2010

The average U.S. Navy vessel has 80 different antennae bristling out of it like a spiny beetle. But it’s often hard to find adequate space for all of them without interference, and their height can expose the ship to radar detection. What if they could be replaced using something a ship always has plenty of: seawater?

It’s not a new kind of Super Soaker, it’s a military-grade antenna.

Daniel Tam, an engineer at Spawar Systems Center (sort of a DARPA for the Navy), exploited the magnetic induction properties of salt water to create an electrolytic fluid antenna which can broadcast and receive VHF and UHF signals.

The design is simple: just shoot a thin stream of seawater through an electromagnetic coil called a current probe, and presto – instant radio communication. A jet 6 feet tall will operate on VHF, and 2 feet gets you UHF. Current probes can be easily stacked and installed anywhere on the deck, because the water-streams can simply be turned off when they’re not in use.

The tech makes sense on land, as well – especially for restoring emergency communications in a crisis area whose power grid has been knocked out. Dump rock salt into a bucket of fresh water, foot-pump it through some plastic pipe with small solar- or generator-powered current probe, and flood victims or emergency-response personnel could be on the air much faster.

The fluid antenna’s range has been successfully tested at 30 miles, and the Navy is seeking commercial partners for the patent-pending technology. Expect neo-survivalist types to start stockpiling these babies faster than you can say “peak oil”.

[Read more at SSC Pacific]

Cut off? Read unlimited articles today.

Become an Insider
Already an Insider? Log in.
Want more award-winning journalism? Subscribe to MIT Technology Review.
  • Print + All Access Digital {! insider.prices.print_digital !}* Best Value

    {! insider.display.menuOptionsLabel !}

    The best of MIT Technology Review in print and online, plus unlimited access to our online archive, an ad-free web experience, discounts to MIT Technology Review events, and The Download delivered to your email in-box each weekday.

    See details+

    12-month subscription

    Unlimited access to all our daily online news and feature stories

    6 bi-monthly issues of print + digital magazine

    10% discount to MIT Technology Review events

    Access to entire PDF magazine archive dating back to 1899

    Ad-free website experience

    The Download: newsletter delivery each weekday to your inbox

    The MIT Technology Review App

  • All Access Digital {! insider.prices.digital !}*

    {! insider.display.menuOptionsLabel !}

    The digital magazine, plus unlimited site access, our online archive, and The Download delivered to your email in-box each weekday.

    See details+

    12-month subscription

    Unlimited access to all our daily online news and feature stories

    Digital magazine (6 bi-monthly issues)

    Access to entire PDF magazine archive dating back to 1899

    The Download: newsletter delivery each weekday to your inbox

  • Print Subscription {! insider.prices.print_only !}*

    {! insider.display.menuOptionsLabel !}

    Six print issues per year plus The Download delivered to your email in-box each weekday.

    See details+

    12-month subscription

    Print magazine (6 bi-monthly issues)

    The Download: newsletter delivery each weekday to your inbox

/3
You've read of three free articles this month. for unlimited online access. You've read of three free articles this month. for unlimited online access. This is your last free article this month. for unlimited online access. You've read all your free articles this month. for unlimited online access. You've read of three free articles this month. for more, or for unlimited online access. for two more free articles, or for unlimited online access.