Jeff Liebermann wrote:

Well, diodes don't have a Q factor, so that's not relevant. The
various resonant circuits and antennas all have a Q. Broadband
devices are inherently low Q, so they won't be very efficient for
detection and retransmission. The 13.56 MHz loop could have been
designed with a fairly high Q, except that body capacitance would ruin
the tuning. So, my guess(tm) is that it's also a low Q device. The
various RF elements might all be very wide band, but that doesn't
offer much if the signal levels and efficiencies are so low as to be
useless.


I'm obviously out of date 8-) and more than slightly astonished.
So, I can walk into a facility posted "no cellphones or cameras"
carrying a turned-off cellphone with a camera plus bluetooth and
not be found out so long as I don't turn it on? Most surprising!

Thanks for writing,

bob prohaska