Extreme Terrain
4x4Wire Trail Talk Forums: Jeep, Toyota, Mitsubishi, Pajero, Isuzu, Kia, 4WD, 4x4, SUV, Off-Road and OutdoorWire Forums


Search

Recent Posts on TrailTalk
Smoking winch
by 4x4Wire - 04/12/21 01:04 AM
Mitsu shift shaft, Sport or Gen 3
by OldColt - 04/08/21 12:07 PM
suzi the psychic
by rascott - 04/08/21 06:06 AM
Power steering pump leak.
by rascott - 04/08/21 05:37 AM
replace master cylinder
by nvmonty - 04/08/21 03:21 AM
Ignition Coil
by Trailmonkey - 04/06/21 06:18 PM
OG folks chime in!
by OldColt - 04/06/21 04:38 PM
Support 4x4Wire
New Topics on TrailTalk
Smoking winch
by OldColt - 04/10/21 07:54 PM
Power steering pump leak.
by Trailmonkey - 04/08/21 04:18 AM
replace master cylinder
by nvmonty - 04/07/21 05:29 AM
CAD delete, a bit different way
by OldColt - 04/06/21 08:58 AM
Mitsu shift shaft, Sport or Gen 3
by OldColt - 04/05/21 12:10 AM
Gen 1 starting issue
by Oso - 04/01/21 05:28 AM
4x4 Gallery
Photos of rig
Attila
99 Monterrible Sport
Scar the Cylon Raider
Mercenary Sergeant: Code Name "Sapphire"
More News on the 'Wire

4x4Voice
4x4Wire
MUIRNet-News
OutdoorWire
Who's Online Now
0 registered members (), 123 guests, and 3 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums37
Topics138,201
Posts1,081,246
Members15,181
Most Online907
Dec 28th, 2019
Previous Thread
Next Thread
Print Thread
Rate Thread
Liquid Radio #1019753 02/03/11 07:31 PM
Joined: Nov 2001
Posts: 3,272
Oyaji_Jon Offline OP
Roll Me Over
***
I received this article via my Navy email account. While not directly related to the 4x4 world, I thought it was interesting.

The Economist
January 29, 2011

Military communications

Liquid Radio

America's navy is developing an antenna made of seawater

A big American warship bristles with more than 100 large copper antennae that send and receive signals for its weapons, its radar and its voice and data communications. A lot of aerials, then, but still not enough. The navy wants its ships to carry even more of them. Fulfilling that desire has, however, stymied experts for decades. If placed too close together, antennae interfere with each other's signals. They also get in the way of aircraft and weapons. And, crucially, naval antennae—many of them more than 20 metres tall—make warships more easily visible to enemy radar.

At the American navy's Space and Naval Warfare Systems Command (known as SPAWAR for short), in San Diego, a team of more than 30 engineers is trying to solve such problems. In 2007 the team's leader, Daniel Tam, thought of a possible answer, appropriately enough, while taking his morning shower. The sodium and chloride ions in salt water conduct electricity. Could a spout of seawater, he mused, replace a metal antenna?

After a trip to a hardware store, Mr Tam discovered that indeed it could. With an $80 water pump, a $15 rubber hose and a $20 electrical device called a current probe that was easily plugged into a hand-held radio, he produced a spout roughly four metres tall from the waters of San Diego Bay. With this he could send and receive a clear signal. Over the intervening years his invention, dubbed the "pee antenna" by incredulous colleagues, has been tweaked and improved to the point where it can transmit over a distance of more than 50km (30 miles).

To make a seawater antenna, the current probe (an electrical coil roughly the size and shape of a large doughnut) is attached to a radio's antenna jack. When salt water is squirted through the hole in the middle of the probe, signals are transferred to the water stream by electromagnetic induction. The aerial can be adjusted to the frequency of those signals by lengthening or shortening the spout. To fashion antennae for short-wave radio, for example, spouts between 18 and 24 metres high are about right. To increase bandwidth, and thus transmit more data, such as a video, all you need do is thicken the spout. And the system is economical. The probe consumes less electricity than three incandescent desk lamps.

A warship's metal antennae, which often weigh more than 3½ tonnes apiece, can be damaged in storms or combat. Seawater antennae, whose components weigh next to nothing and are easily stowable, could provide handy backups—and, eventually, more than backups. Not all of a ship's antennae are used at once, so the spouts could be adjusted continuously to obtain the types needed at a given moment. According to SPAWAR, ten such antennae could replace 80 copper ones.

Fewer antennae mean fewer things for enemy radar to reflect from. Seawater is in any case less reflective of radar waves than metal. And if a ship needed to be particularly stealthy (which would mean keeping its transmissions to a minimum), her captain could simply switch the water spouts off altogether.

One disadvantage of water spouts is that they can be torn apart by the wind. SPAWAR's researchers have, however, found that their antennae work just as well if encased in a plastic tube. The tube can be sealed at the top so that the water goes up the middle, bounces off the top and then trickles down the inside of the tube's wall to the bottom, where it may be recycled.

That innovation also means that SPAWAR's invention need not be restricted to the navy. The closed-tube design allows saline aerials to be deployed on land, too. Indeed, one has already been tested successfully by a group of marines. It worked, as expected, with brine made from fresh water and a few pinches of salt. But if salt is not to hand, never fear. It also worked fine when the spout was fed with Gatorade.


73
-Jon
KJ6GVM

As seen on Expedition with TX plates: VEGETARIAN - An old Indian word for poor hunter

Grampa's Trooper
1974 FJ40
1987 FJ60
Support our sponsors
Re: Liquid Radio [Re: Oyaji_Jon] #1019754 02/03/11 10:55 PM
Joined: Feb 2000
Posts: 6,239
4x4Wire Offline
Trail Leader
***
It is an interesting concept.

In my days on the old FRAM I destroyer, working antennas were always an issue.

The biggest issue was when we lost the surface search radar antenna during a stormy night in the middle of shipping lanes in Tokyo Bay.

An "on-board emergency spare" would have been nice!!! Perhaps someday it will be a reality.


John Stewart
Editor - 4x4Wire.com
Editor - 4x4Voice
Editor - MUIRNet-News
President - BlueRibbon Coalition
Re: Liquid Radio [Re: 4x4Wire] #1019755 02/07/11 06:18 AM
Joined: Oct 2002
Posts: 15,887
kewlynx Offline
Toyota & Classifieds Moderator
*****
If the Marines are already playing with it, it will be. I call it 'grunt-proofing'.

Tesla would still be laffin' at us. <img src="/forums/images/graemlins/cyclops.gif" alt="" />


http://www.walkablecommunities.org/

Democracy is two wolves and a lamb voting on what to have for dinner. Liberty is a well-armed lamb contesting the vote.

**ubi apis- ibi salus**

Moderated by  4x4Wire, Oyaji_Jon 







4x4Wire Social:

| 4x4Wire on FaceBook |


OutdoorWire, 4x4Wire, JeepWire, TrailTalk, MUIRNet-News, and 4x4Voice are all trademarks and publications of OutdoorWire, Inc. and MUIRNet Consulting.
Copyright (c) 1999-2019 OutdoorWire, Inc and MUIRNet Consulting - All Rights Reserved, no part of this publication may be reproduced in any form without express written permission
You may link freely to this site, but no further use is allowed without the express written permission of the owner of this material.
All corporate trademarks are the property of their respective owners.

Powered by UBB.threads™ PHP Forum Software 7.7.3
(Release build 20190728)
PHP: 7.2.34 Page Time: 0.026s Queries: 15 (0.007s) Memory: 2.8431 MB (Peak: 3.1633 MB) Data Comp: Off Server Time: 2021-04-13 01:40:59 UTC
Valid HTML 5 and Valid CSS