BlackstoneAgain a transmission distance of 1cm is nothing. If you notice credit cards are now including RFID.
http://www.mastercard.com/us/personal/en/a...pass/index.htmlso keep your credit card in a metal case if you are concerned. Do the same with your cell phone or turn it off which is much more powerful. A good example is AM radio signal strength. There are small 1000w to 50KW in strength. The stronger the signal strength the further it transmits. Cell phones origianll were bag phones with I think 3 watts the handhelds are much lower because they transmit microwave energy, do you like putting your head in a microwave oven. No, so they used only I think it was 0.6 watts.
As far as voluntary are ATM cards voluntary?
DaytonRockerCell phones can be tracked without GPS chips in them. A GPS chip makes it easier and more accurate. The cell phone is talking to many antennae at the same time. Your cell phone sends out a unique identifier so they can bill you and know you have an active cell phone. With about three antennae your position can be triangulated. With one they know your approximate location. But there are many out there, they hand you off so to speak to the other antennae as you drive.
I have designed wireless products for years, have been VP of Engineering of one. Think before you go on too far. LCD battery consumption for example is so low…. Ever own a calculator with a LCD or watch, those last for years on VERY small batteries. Now color does take more energy but it is off most of the time. and I can get the specific data of color power consumption but not needed for this debate. Again think about it. The ringer only goes on a very small amount of time also. When you are talking on a phone the battery goes down sooo fast that is because it is sending a LOT of data(RF)… When not talking it only has to send your unique identifier every long period of time. If you want to debate this I am willing to let you start another thread and will participate. Just PM me when you do.
Inverse square is applicable to the electromagnetic spectrum where the signal spreads out into space. Cell phones and RFID tags are in the electromagnetic spectrum. For your reference the antennae is a fixed size and is optimized for the wavelength. Items must pass FCC testing which limits power output. Reflectors behind anteae also gives you a directional gain.
Look at inverse square law.
http://www2.jpl.nasa.gov/basics/bsf6-1.html For those who did not take high school physics, here is a link to high school physics content.
http://kuhn.lewiscenter.org/~mhuffine/subp...sscicsframe.htmAs far as your other questions on metal and RFID interference you can always take a few classes if interested. There are great colleges all over.
Christopher,You are right on using computers on the internet including your listed amazon, we have cookies and so on to add.
You are correct about the circular keys, you stepped out of the norm for them to make you a target. If all cars used RFID it would just about stop car theft your example shows how just a better lock also helps. Our thieves will have to become electronic techs to steal cars, then they will find they can work and make an honest living easier.
I agree with you on the marketers also.