Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!decwrl!labrea!glacier!jbn
From: jbn@glacier.STANFORD.EDU (John B. Nagle)
Newsgroups: sci.electronics
Subject: Re: time capsule
Message-ID: <17332@glacier.STANFORD.EDU>
Date: 1 Mar 88 16:49:31 GMT
References: <3a935422.44e6@apollo.uucp> <1004@PT.CS.CMU.EDU>
Reply-To: jbn@glacier.UUCP (John B. Nagle)
Distribution: na
Organization: Stanford University
Lines: 14
Keywords: thermal power


      Thermocouples may be a good idea here.  Most of the time, there's a
useful temperature difference between the surface and 50' underground.
An old well shaft should be a good source for a few hundred mA.  
Or you could drill your own small hole, which, for moderate depths, is not a
big deal.  Put all the electronics in a cylinder, lower it into the
shaft a short distance, plug the shaft with cement, and cover it over
with dirt, and, in a reasonably undeveloped area, it is not likely to
be bothered for centuries.  

      Underground antennas, just below the surface, are used in military
installations where blast-resistance is desired.  So even the antenna
can be underground, if you can store up enough power to get out despite
the losses.