Xref: utzoo sci.electronics:9851 rec.ham-radio:17235
Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uwm.edu!bionet!arisia!lll-winken!tekbspa!optilink!elliott
From: elliott@optilink.UUCP (Paul Elliott x225)
Newsgroups: sci.electronics,rec.ham-radio
Subject: Re: naive question about RF propagation
Summary: wires in tunnels
Message-ID: <3055@optilink.UUCP>
Date: 30 Jan 90 16:37:12 GMT
References: <28774@amdcad.AMD.COM> <480ec7fd.15840@valley.UUCP> <21957@unix.cis.pitt.edu>
Organization: Optilink Corporation, Petaluma, CA
Lines: 17


An engineer I once worked with told me that the tunnels near the Presidio
(military base in San Francisco) had these wires installed during WW2 so
the base commander (or whatever the military title is) could stay in contact
via two-way radio while driving around.  I believe that the tunnel wires
originally had a tuned external antenna feeding the wire.  You can see what
looks suspiciously like a diplole cut for the middle of the FM broadcast band
on the outside face of some tunnels. It probably works as an untuned antenna
for the AM band.




-- 
Paul M. Elliott      Optilink Corporation     (707) 795-9444
           {pyramid,pixar,tekbspa}!optilink!elliott
                  "The dog ate my disclaimer."