Emergency Seawater Antenna For Ships

It’s pretty easy to make an emergency antenna out of a spare length of wire but… still an interesting concept.

(Then again, for some reason beyond my comprehension the USS Fitzgerald couldn’t get a radio working instead and had to wait until they could limp into port to call mayday via their personal cell phones.)

No information on the standing wave ratio and especially the magnetic core losses which are, I suspect, pretty large. With enough power the core will also heat up which means more losses. What are the losses of the seawater radiator due to the inherent much higher resistance as compared to a copper wire and what about skin effect?

It seems that the inventor isn’t very familiar with ships and the special circumstances in which they operate. He mentioned 80 antennas on a war ship. Imagine the amount of plumbing which is necessary to bring seawater to each antenna and how vulnerable this is for damage to the piping system that can take place on a ship in practice. And how easy is it for the enemy to take out the seawater pump to render all communication equipment useless.

An emergency VHF antenna is with a little imagination easily made. No techies or HAM operator who know how to improvise on board such an expensive ship?

I made this one up just now in seconds, no soldering required. No rocket science either!


I’ll second that.

Every ship I setup my ham rig on used what could be described as an “emergency” antenna. It was a coax to a tuner to a long wire attached to some piece of structure with a view of the world.

No magnets, no pumps, no piping. No person, place or thing disturbed.

I wonder if the water antenna guy uses a fire speaker.


My first thought when I viewed this was Rube Goldberg.

Did you notice the extremely fancy brass ship models? This is the (or one of the) US Navy facilities where they design and place antennas for US Navy vessels. The scale models are used on a scale ocean (of lead, or at least used to be) to work out radiation patterns and near-field interference problems.

The video is infuriating and should have been an hour long, but the people doing the work are the real deal.

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I still call Rube Goldberg. @Dutchie nailed it with a common sense observation. I’d have to see a field strength or RF measurement compared to a simple wire antenna properly matched to the transmission line with the hull or sea water ground. Until then, I think I hear the suction vortex of our tax dollars…


That and so much else is what the rest of the hour video would be. And it’s not as though they don’t have the gear there to make proper tests.

I notice nobody talks about what happens when the wind blows.




I was going to but you beat me to it…:wink:

Above I already said that ships are operating in special circumstances, bad weather is one of them. I don’t know at what wind speed the sea water radiator will start to break up and eventually vaporize. I suspect that even with zero wind speed and with a naval ship that can run up to 30 knots that this could already be enough to desintegrate the radiator.

The same problem will occur with heavy rainfall and especially the torrential downpour in tropical areas. All communication will be knocked out.

The demonstration with the handheld with flat water at hand is not what we encounter on board a ship. On bridge level you need a bucket with sea water, not very practical. You also need a large battery for the pump that normally eats quite a bit of current. And all that to replace a small piece of wire.

I have more faith in this Chinese steerable beam antenna. The acrylic tubes can be filled with sea water to different levels by micro-pumps. When the tubes are emptied they are virtually undetectable by radar etc.

That’s when you break out the kite.

Way back when, my father in law could get cable in Outer Banks using tin foil on an antenna strategically placed. He got the Leon Spinks fight when no one else could. WW2 telephone guy that aided communications before DDay in England and a longtime AT&T employee/manager afterwards. I miss him dearly.


I still have a foldable box kite lifeboat transmitter antenna from I believe a Disa Marinetta set. We used to test them on board and of course lost one… They were easy to fly and once up they stood like a rock. The box kite was part of the German NSG2 ‘Notsender’ (Emergency Transmitter) one of which was captured in 1942 and immediately copied and adopted by the Allied Navies.

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Made a trip to Peru around the turn of the century. I had a box kite with 150ft wire. 5/8 wave on 3.9 megs. I worked the guys in our club almost every night we were underway on 75 meters SSB with 100 watts. The wire finally broke on the trip back.


injunear: … pretty good !! I used verticals aboard but up north (around 60 deg
N) didn’t get much (40M) till the antenna side was facing south.
I missed the ghist of this article but saw the comment a ship couldn’t put together a RF signal, well … so much for the radio officer huh? (and they usually have such enviable equipment)
PS: I’ve been using my IC7200 but found ye ole IC740 does 200 watts !, starting to like it.

That’s why it’s best to have the base and vertical section free and clear as possible. Some times use it to your advantage.
I was on a delivery of a fish processer to the PNW back late '70s. An old YOG. The SSB radio highest freqs was 8 mhz with the standard 35 ft whip. After clearing the Panama Canal, we were having a tough time working KMI San Francisco. I used the fwd rigging to erect a full wave wire triangle driven element mounted about 20 ft forward of the superstructure. We had no problem working KMI on the trip up.

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