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From: wrf@mab.ecse.rpi.edu (Wm Randolph Franklin)
Newsgroups: sci.electronics,rec.ham-radio
Subject: Re: naive question about RF propagation
Message-ID: <*BR#`|@rpi.edu>
Date: 16 Jan 90 22:49:27 GMT
References: <28774@amdcad.AMD.COM> <480ec7fd.15840@valley.UUCP>
Organization: Rensselaer Polytechnic Institute, Troy NY
Lines: 17

In article <480ec7fd.15840@valley.UUCP> pfluegerm@valley.UUCP (Mike Pflueger) writes:
>
>Actually, I had this as an EE problem to solve in college - how the tunnel
>could be modified to pass signals of a frequency above cutoff.  One way
>was to modify the u (mu) of the material in the tunnel - such as a special
>gas, or styrofoam, obviously impractical.  The real way was to run a wire
>through it which extended outside the tunnel.  The wire would conduct the
>RF into the tunnel and allow reception.  I forget the exact details on
>length of the wire, but this was in a course taught by John Kraus (Mr.
>Antenna) himself, so I'm confident of the solution.

Don't (some) subway systems use this so the crew can use radios?
-- 
						   Wm. Randolph Franklin
Internet: wrf@ecse.rpi.edu (or @cs.rpi.edu)    Bitnet: Wrfrankl@Rpitsmts
Telephone: (518) 276-6077;  Telex: 6716050 RPI TROU; Fax: (518) 276-6261
Paper: ECSE Dept., 6026 JEC, Rensselaer Polytechnic Inst, Troy NY, 12180