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[bob ford <bobford79 AT yahoo.com>]

James, I knew that Don was right, I just didn't know how to explain what I 
had read.  This is part of the article from Scientific American,  They did 
say "broadcast" but I had the signal running backwards.  The person writing 
the article wasn't wrong --  I  was .   I might not ever completely 
understand the technology, but I know I don't like the significance of its 
use .......bobf
 
How RFID Tags Could Be Used to Track Unsuspecting People 
A privacy activist argues that the devices pose new security risks to those 
who carry them, often unwittingly
By Katherine Albrecht 
  

Average consumers may not realize how many RFID tags they carry around. The 
devices are embedded in personal items and even some clothing. 

Melissa Thomas (photoillustration); Richard Schultz (RFID tags); Sam Jordash 
(woman); Burazin (key fob); ©2005 Transport For London (Oyster card); 
Identity Stronghold (passport sleeve); Dima Gavrysh AP Photo (Chase blink 
credit card); Rolf Vennenbernd DPA/Corbis (EAS/RFID); Washington Metropolitan 
Area Transit Authority (SmarTrip card)
Key Concepts
    * Radio-frequency identi­fication (RFID) tags are embedded in a growing 
number of personal items and identity documents. 
    * Because the tags were designed to be powerful tracking devices and they 
typically incorporate little security, people wearing or carrying them are 
vulnerable to surreptitious surveillance and profiling. 
    * Worldwide, legislators have done little to address those risks to 
citizens. 
If you live in a state bordering Canada or Mexico, you may soon be given an 
opportunity to carry a very high tech item: a remotely readable driver’s 
license. Designed to identify U.S. citizens as they approach the nation’s 
borders, the cards are being promoted by the Department of Homeland Security 
as a way to save time and simplify border crossings. But if you care about 
your safety and privacy as much as convenience, you might want to think twice 
before signing up.
The new licenses come equipped with radio-frequency identification (RFID) 
tags that can be read right through a wallet, pocket or purse from as far 
away as 30 feet. Each tag incorporates a tiny microchip encoded with a unique 
identification number. As the bearer approaches a border station, radio 
energy broadcast by a reader device is picked up by an antenna connected to 
the chip, causing it to emit the ID number. By the time the license holder 
reaches the border agent, the number has already been fed into a Homeland 
Security database, and the traveler’s photograph and other details are 
displayed on the agent’s screen


----- Original Message ----
From: "Clansgian AT wmconnect.com" <Clansgian AT wmconnect.com>
To: homestead AT lists.ibiblio.org
Sent: Monday, September 15, 2008 9:58:59 AM
Subject: Re: [Homestead] Conspiracy, Power, Privacy, and THEM



> >As you can tell Don, although I've done a lot of reading in the scientific 
> journals, I don't know how to explain what I've read correctly.  But I 
> could 
> have sworn that the verb broadcast was used in one of the articles--- but 
> you are correct.

Don's a radio man and knows what he's talking about.  It is not possible for 
the same thing to be passive and also broadcasting continuously.  That's like 
saying "this joint is concave but it's also a mortise".  

Lots of people who write articles are quite ignorant of electronics.

RFID tags are viewed as coming in three flavors:

Active - have a built in power source, usually a battery.  The battery powers 
the passive circuitry and powers the oscillator for transmission.

Passive - has no built in power source.  RF energy is received (detected) and 
charges a small capacitive or inductive circuit. Sometimes only the junction 
of a CMOS is charged.  This is enough power to transmit a brief signal in 
response.

Have you ever had the experice of turning off a radio and unplugging it and 
when you switch it on again without plugging it up, it plays for about a 
second 
then fades off (and you discover it is unplugged)?  That's because the rather 
large capacitors in the power supply (that convert the AC to lower voltage 
DC) hold a charge even unplugged.  This is enough power in fact to opearate 
the 
radio for a second or two.  That's how passive RFID circuits work.  Radio 
frequency energy of a specific frequency causes and induced current which is 
stored (for a microsecond) as an inductance or a capacitance and powers the 
response transmission.

The process is not so much like a "transciever" as I am making it sound.  It 
is not like the PTT button on a CB radio - listen thent talk.  It functions 
more like a 'backscatter' of the original RF signal that excited it.

A third type is the semi-passive RFID in which a battery powers the passive 
circuitry but the trurn signal is just a backscatter.



Obviously a device without a power source can be made much, much smaller than 
one with.  For example, the working guts of your cell phone is no bigger than 
a the nail on your little finger, the rest of the bulk and weight of the 
phone is the battery.  

But the signal that provokes the active RFID or the semi-passive RFID into 
action can be a very tiny (weak, in microwatts) signal.  To get the same 
results, the RF signal to activate a totally passive RFID must be more than 
100 times 
stronger.  It is a massive heathen transmitter that is activating a passive 
chip more than a very few feet.


James, WA4CYU  </HTML>
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