underwater GPS?

Mark Eakin eakin at ogp.noaa.gov
Wed Jun 24 15:52:10 EDT 1998

                           Subject:                         Time:   10:52 AM
                           RE>underwater GPS?               Date:   6/24/98

GPS works using a near-microwave radio signal transmitted from the satellites.  These frquencies have no ability to transmit through water.  The greatest loss (attenuation) of signal in the atmosphere is due to water vapor.  Just think about what happens when you place water in a microwave -- the water gets hot due to exchange of energy from the microwaves to the absorbing material.

Most marine GPS units are water resistant and can be used at the surface while snorkeling.  The unit could be placed on a surface buoy tethered to a scuba diver.

It is POSSIBLE to have a surface antenna with a coaxial cable run to a submerged GPS.  However, the signal losses over coaxial cable are so high that this would not be practical.

Cheers, Mark

Date: 6/23/98 6:43 PM
To: Mark Eakin
From: eric roach
Does anyone possess product information for any sort of underwater GPS 
or any ideas of how to make one?

Eric Roach

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