PAYG to get free Wifi on London Underground

gjchester

macman wrote: »

The possibility of bombs on trains being remotely triggered by phones is another reason that TFL were less than keen on introducing mobile access onto trains themselves, as opposed to just in stations. After 7/7, that's hardly surprising.

Conspiracy theories aside it's more to do with , the fact the tunnels are not straight (so you can't stick a big aerial at one end), the train clearances in the tunnels and the size of transmitting antenna needed, you'd be looking at replacing the antennae every time a train went past, as there's just not enough space between the train and the tunnel.


LUL has radios that work in tunnels, and timers would work just as well as a remote signal.

buglawton

gjchester wrote: »

Conspiracy theories aside it's more to do with , the fact the tunnels are not straight (so you can't stick a big aerial at one end), the train clearances in the tunnels and the size of transmitting antenna needed, you'd be looking at replacing the antennae every time a train went past, as there's just not enough space between the train and the tunnel.


LUL has radios that work in tunnels, and timers would work just as well as a remote signal.

You can probably manufacture a type of cable that has a transponder every so many metres, or even a 'leaky feeder' concept as used to distribute radio into tunnels. Then you just roll out this cable along the track via an adapted train, like ships lay fibre undersea. Transponders under the carriages pick up the signal. But this type of R&D does not appeal to short termist investors.

The tech already exists for undemanding situations:
http://www.solwise.co.uk/downloads/files/leaky-feeder-cable-introduction.pdf

bsms1147

If they wanted to do it they could run it through the tracks themselves, much like how 'Broadband over Powerline' works in the home.

No issues with wireless strength or curves in the tunnels.