London Banter - View Single Post - BBC discovers that Oyster users can be overcharged for incomplete journeys

Roland Perry · March 11th 11, 09:30 AM posted to uk.transport.london

In message , at 10:09:43 on Fri, 11 Mar
2011, d remarked:
Given a powerful enough directed RF signal you could certainly
power up and send signals to an Oyster card from a distance.

Only of you wanted to fry the human holding it, at the same time

Why? It shouldn't need much more power than you'd get from those shop
security gates.

The security tags have an internal power source.

You sure about that? I've seen a few with spiral antennas but no battery as
they were flat and flexible. I'm pretty sure the RF powers them up.

There are different sots of security tag, just like there are different
sorts of "RFID" tag inside transport cards, or used for things like road
tolls. Much confusion arises when people assume these are all the same
technology.
--
Roland Perry