I see the BBC reporters don't understand RFID tags.

Andrew submitted this idea :

Well, better than the shoebox I grew up in, on the hard shoulder of the M1..

You do know what the RF in RFID stands for don't you?

Radio frequency does not necessarily imply radio (electromagnetic) waves. In fact, if you have an RF magnetic field generated there will be some EM radiation around. But I believe if is purely the near field magnetic induction at RF that excites the tag. I also believe, but my knowledge is limited, that RF excited tags exist for some purposes, but are not the common ones. ICBW

Well that was a bit confused. in the last whole sentence I meant of course that *radio wave* excited tags exist for some purposes where the reader cannot be close enough to the tag for magnetic excitation.

Google 'near field far field'

You mean the M1 was built and you had a hard shoulder? When I were a lad...

I think you are probably wrong on both counts these days.

Doesn?t explain the obvious RF antenna in the pic someone posted. That?s not a coil.

Ultimately there is sod all difference.

Magnetic, capacitative or RF coupling are all just termns that are used to ID what mode predominates. At a few feet at GHz frequecies its RF. You are well into far field

readable from up to 8m away, that's not near field.

The lines between coils and antennae are blurred.

Ultimately when you do teh math omn EM radiation (and I did, once) what pops out is thet 'capacitatative coupling' 'magnetic coupling;' ' RF power transfer' are all really the same thing - explication of the nasty tensor calculus that defines 'elecromagnetic fields'.

It is just that in some case you can use a simplified version and get roughly the right answer and call that 'induction' or 'RF' or 'capacitative coupling'

Do they go that far?

Impressive!

Still obviously RF and not magnetic field as dense claimed.

Not with that one, there is no coil at all.

Irrelevant to whether that RFID has an antenna or a coil.

Irrelevant to whether that RFID has an antenna or a coil.

But most RFID devices of the type we are talking about work at cm distancess, or inside large coils. The ones that work at a few feet are different.

I'd ask what definition of "radio wave" Dennis was using. My OED gives " an electromagnetic wave of the kind used for radio; a radio-frequency wave". The latter part of that seems to guarantee it is apt for RFID.

And while in the OED, it has as an example of RFID from 2004

"...the microchips?called Radio Frequency Identification (RFID) labels? remain active over a range of five metres once the product leaves the store."

Some councils have done just that. They have been stacked together 2 high, and internally cut so that 2 or more containers make one space.

they have upvc DG are fully insulated, heated and electrically save, and surrounded by gravelled areas for kids to play. For temporary, or even no-so-temporary accommodation they are godd idea. At some point they can just be lifted apart and sold and the site used for something else.

Years ago these people would have been put in residential 'park' caravans, miles from anywhere.

Perhaps the residents who are mostly single mothers should get their lives in order before banging out kids and expecting the nanny state to provide for them ?.

Isn't it just a diode that acts as a frequency doubler so they can detect that new frequency when you pass the coils activating it?

What is smart about it?

The link was the BBC tv and radio news items where the BBC guardian- reading journos simply ran a story that a charity provided. Standard BBC output.

The impression that the news item gave was that people were being made to live in "shipping containers" when in fact the shipping containers had been converted into insulated, heated, DG glazed studio flats complete with cooking and bathroom facilities. These are fine for temporary acommodation.

Just another attempt to con the public into thinking that the taxpayer (and future taxpayers not even born yet) need to pay billions to build nice houses for people to live in for a peppercorn rent, and after a short time, exercise their 'right to buy' and trouser a massive profit.