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Participant

Join Date: May 2008
Posts: 1

Radio wave transmission in water

05/12/2008 5:53 PM

Hi,

I'm thinking of designing a product which requires radio wave transmission in water. I'm thinking of using a transmitter that is as small as a car remote. Is it at all feasible?

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Pathfinder Tags: Radio wave transmission Water
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Anonymous Poster
#1

Re: Radio wave transmission in water

05/12/2008 6:01 PM

Yes, but don't you know that underwater radio waves kill fish and contribute to global warming?!?

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Guru
Engineering Fields - Control Engineering - New Member China - Member - New Member

Join Date: Sep 2006
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Good Answers: 14
#2

Re: Radio wave transmission in water

05/12/2008 10:35 PM

No! certainly not!!!!

you can read some science popular reading at first. I think.

radio signal cannt transmit in the water.

water has strongly absorb radio signal. to provide this people sometime has t o use very long wave for their communication. and transmitter is very large.

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Power-User
United States - US - Statue of Liberty - Sworn to preserve and protect Engineering Fields - Nanoengineering - How tiny is it? APIX Pilot Plant Design Project - Member - Good idea. Engineering Fields - Engineering Physics - Engineering Fields - Energy Engineering - Energy in Transition

Join Date: Nov 2007
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#3

Re: Radio wave transmission in water

05/16/2008 10:15 AM

RF propagation underwater is doable. Attenuation is an issue. Success depends on Range of transmission, strength of the signal, sensitivity of the receiver and the frequency of the transmission and type of contaminates in the water. (Russian and US Navy (and others) have used used RF to communicate to submarines at operating depth around the world using Extremely Low Frequency (ELF) systems.)

You might try a Google search. Google Scholar should be helpful, as well.

There are commercial systems for submarine RF communication. I have no experience with them.

Acoustics are more commonly used for communication (both voice and data) in the marine environment.

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Member

Join Date: May 2008
Posts: 5
#4
In reply to #3

Re: Radio wave transmission in water

05/16/2008 10:55 AM

It is worthy to include another EM technology in this discussion. Blue-green lasers are increasingly common medium for marine communications. It is a very popular military option to submarines from other marine vessels, as well as from aircraft and other platforms.

I cannot know if it would be helpful in your application.

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Participant

Join Date: May 2010
Posts: 1
#5

Re: Radio wave transmission in water

05/02/2010 10:02 AM

Communication can take place at low frequencies but due to the conductivity of water the signal will attenuate very rapidly as transmission frequency is increased. I have sucessfully transmitted data at 100 bits per second at 3000Hz using BPSK modulation. The distance is limited to about 15m in practice although theoretically this could be greater. The antenna is physically a problem so forget a remote control size. We have reduced ours to about a metre across! See the following website for the equations that will give you ideas of viable transmission distance etc.

http://www.qsl.net/vk5br/UwaterComms.htm

see Wireless Fibre Systems for commercial underwater modems using RF tchnology

http://www.wirelessfibre.co.uk/

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