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From: dnc%dartmouth.csnet@csnet-relay.arpa
Newsgroups: net.physics
Subject: Re: passing <large amouts of information through> water
Message-ID: <13305@sri-arpa.UUCP>
Date: Sat, 8-Sep-84 17:49:35 EDT
Article-I.D.: sri-arpa.13305
Posted: Sat Sep  8 17:49:35 1984
Date-Received: Fri, 14-Sep-84 08:33:55 EDT
Lines: 31

From:  David Crespo <dnc%dartmouth.csnet@csnet-relay.arpa>

troy:
    thank you for the transmission. 
    low freq -> high wavelength -> large receiver.
    in space, the problem is not present, so they propose
    using high freq (microwave) signals to send information.
    those antennae are still big (100 ft diam???) and
    i assume they would have to be even bigger to take into 

    account both the index of refraction of the medium 
    (elf i think would travel at c/n = f (lambda)) and
    the attenuation (which i don't know how it works,
    physically, though it has to do with energy lost, entropy,
    diffraction around objects(?)(might be a small 
    significant problem since object smaller than
    the wavelength. this, i assume, would call
    for a quantum mechanical description), 
    and any other couplings applicable.
 
    (is hte above correct?)
 
    (no, ...)
 
    but, i assume they are not trying to transmit 
    sound, but e-m. yes. they must. i thought of
    wondering if they could proceed by analogy to
    sea animals, if any of them communicate over
    such long distances? 
 
    what about telescoping antennae on a sub?