On Mon, 15 Dec 2003 06:59:30 GMT, said...
Paul Burridge wrote:

I'll add that my Optoelectronics handi-counter's fsm bargraph can detect
a few hundred milliwatts at several feet away.

I visualize a radio-field power density being grid-lines painted on a
balloon around a 1/2 wave dipole. As the balloon is blown up, the
grid-line expand, given by 4 pi r^2.

For some good app notes on designing electrically small antennas and
radio link calculations:

Goto -
http://www.rfm.com/corp/apnotes.htm

Checkout:
http://www.rfm.com/corp/appdata/antenna.pdf
http://www.rfm.com/products/tr_des24.pdf

HP (now Agilent) has some app-notes on designing diode detectors, and
has some utility programs that will help you design and calculate
performance. Some I think, in context of RFID reading devices. But they
point out you get a square-law for small signals, which gets nonlinear
for larger signal levels. And what bias the detector diode has on it.



Any particular search string to use for that Agilent stuff? They're
usually good for info on stuff like that.

Mike