[TowerTalk] Radio's/tunnels

[Roger Borowski]

Radiax has a similar appearance to Heliax. It is made by Andrew Corp. for use in
tunnels and underground mining caves as it has a continuous small void area in
the shielding allowing it to be fairly low loss, like heliax, but radiates
whatever RF signal it carries along its entire length. In applications where it
is used, it is common to use miles of it and just a dummy load on the far end.
Rog-K9RB
----- Original Message -----
From: Curtis, David B <david.b.curtis@intel.com>
To: Robin E. Midgett <rmidgett@bellsouth.net>; <towertalk@contesting.com>
Sent: Thursday, May 04, 2000 11:39 AM
Subject: RE: [TowerTalk] Radio's/tunnels


>
> *I* haven't heard of Radiax. Please tell us about this wonderous product.
> 73, Dave N6NZ
>
> -----Original Message-----
> From: Robin E. Midgett [mailto:rmidgett@bellsouth.net]
> Sent: Wednesday, May 03, 2000 6:29 PM
> To: alsopb; towertalk@contesting.com
> Subject: Re: [TowerTalk] Radio's/tunnels
>
>
>
> I wonder if the D.C. services ever heard of Radiax?
>
>
> At 08:16 AM 5/2/2000 +0000, alsopb wrote:
>
> >This is an extract from the Wash. Post.
> >
> >Radios Hampered Response to Metro Fire
> >
> >By Lyndsey Layton
> >Washington Post Staff Writer
> >Tuesday , May 2, 2000 ; A01
> >
> >Trapped passengers could have been rescued and subway service restored
> >in 70 minutes instead of four hours, if the telephones and radios of
> >the D.C. fire department had not repeatedly cut out or temporarily
> >gone dead, Metro officials said yesterday in a review of the April 20
> >tunnel fire.
> >
> >Firefighters who rushed to the tunnel between the Farragut West and
> >Foggy Bottom stations shortly after 5 p.m. found themselves in a
> >"communications blackout," unable to talk to each other on their
> >hand-held radios or to Metro officials on their cellular telephones,
> >said Fred Goodine, Metro's chief safety officer. Fire officials say
> >they
> >still don't know what caused the problems.
> >*********************************************************
> >
> >Have people strayed so far from reality that they don't realized
> >radios don't work in underground tunnels?  This
> >ignorance/unpreparedness could have cost lives.
> >
> >They say later in the article that they will have to string "antennas"
> >in the tunnels in the future.
> >
> >It is a tribute to the RF engineers that radios are so reliable in so
> >many instances that people take them for granted and forget they have
> >limitations.  Their "success" lead to these problems.
> >
> >de Brian/K3KO
> >
> >--
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> 73,
> Robin E. Midgett KB4IDC EM66se
> rmidgett@bellsouth.net
> 1/2 of the Award Winning NT4L Rover Team
> http://www.almostanywhere.com/vhf/vhf.html
>
>
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