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[email protected] · September 22nd 10, 11:33 PM posted to uk.transport.london

In article , (Roy
Badami) wrote:

On 22/09/10 11:55, Recliner wrote:

I don't think it was ever more than a plan. And I think originally it
was only going to work in stations, not the tunnels between them.

I'm almost certain there were at least plans to have it work in the
tunnels, because I remember the discussion of leaky feeders at the time.

Basically, you run a piece of coax along the tunnel (that's the feeder),
and at intervals the shielding is removed from a short length of coax,
which causes the feeder to leak RF (i.e. act as an antenna).

You need leaky feeder to cover the stations too, Roy. We provided PMR
cover to all the underground stations not already provided in a big
contact when I was still at Philips. I have a map somewhere with the
stations involved marked. Only those actually under the ground of course.
It was done after the King's Cross fire.

--
Colin Rosenstiel