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From: robw@brb.isnet.inmos.co.uk
Newsgroups: sci.electronics
Subject: More Data xfer UNDERWATER !
Message-ID: <446.27f9b921@brb.isnet.inmos.co.uk>
Date: 3 Apr 91 11:14:41 GMT
Organization: Inmos Limited
Lines: 38

>I need to transmit some data between two systems about 10 feet apart
>without being physically connected.  
>They will not always be line-of-sight, and they may be UNDERWATER !

>Any suggestions ?

Thanks to all who have responded.  A lot of responses have been questions
requesting more information so here is a more detailed requirement.

  The data being gathered is water temperature, currents, light levels
  and depth.

  The unit will be operated down to depths of around 100 metres.

  I need a bandwidth capable of supporting 1200 baud.

  I need two types of units one capable of transmitting about 10 feet
  the other about 50 feet.  

  There will be a few operating at the same time sending data to a 
  central unit. So I need to use some sort of coding.

  Some units may be hidden from the main unit by small rocks, hence
  not always in line of sight.

  FM (FSK) would perhaps be the best modulation technique, AM is
  rather prone to noise.


  I hope this stimulates more discussion.

    Rob Wadsworth.

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Rob Wadsworth   Inmos Ltd Newport GWENT UK   | EMail:  robw@isnet.inmos.co.uk
    Tel +44 633 413443 ext 269               |  
    Fax +44 633 412925                       | My own thoughts etc...........
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