Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!cica!gatech!emory!stiatl!john
From: john@stiatl.UUCP (John DeArmond)
Newsgroups: sci.electronics
Subject: Re: radio reception
Message-ID: <6012@stiatl.UUCP>
Date: 23 Jul 89 22:41:52 GMT
Reply-To: john@stiatl.UUCP (John DeArmond)
Organization: Sales Technologies Inc., "The Procedure IS the product"
Lines: 18

In article <3890@phri.UUCP> roy@phri.UUCP (Roy Smith) writes:
> The system you mention is probably the 'leeky feeder'. This can be used
> in tunnels, where you place an antenna outside to pickup the radio
> signal, an retransmit it on the coax cable. If the cable has some slots,
> you will experience an electromagnetic field, radiating from the cable.

This is known by the brand name Leakiax.  It is standard fare in most
of the nuclear plants I've work.  It is used to provide 2-way radio
contact in all the shielded rooms in these plants.  

The Leakiax I looked at consisted of 7/8" hardline with a narrow 
longitudinial slot cut in the shield.  This slot was segmented into
sections about a foot long.  Don't know if this was some sort of tuning
or just manufacturing convenience.
-- 
John De Armond, WD4OQC                     | Manual? ... What manual ?!? 
Sales Technologies, Inc.    Atlanta, GA    | This is Unix, My son, You 
...!gatech!stiatl!john    **I am the NRA** | just GOTTA Know!!!