Thanks Josh... me by accident referenced TRF79xx.. (fingerproblem here).
Johan, please confirm your detection "ceases" as the Tag gets too close, ie <2.5cm
Josh your strategy seems to be solving an opposite problem, you are trying to arrange to harvest more energy by asking for a "higher Q" ?
In addition you recommend for "more" emitted charge field energy from the basestation board...ie use 12V etc...Johan seems happy with 7cm?
Johan, are the two coils facing each other as your TMS37157 device approaches (face-on or side-on?) your "custom built reader and or the original TI TMS3705 PCB. and how did you come by your coefficient of coupling figure, was it based on the ratio of coil apertures?
As you suggest, the problem does follow the "new coil"... therefore is it not the issue... and yet all it has is Aperture/Shape//Q/(DC and AC resistance) stray capacity and companion objects....choose one!
Josh, if the Q is to low as you propose ( and Johan does say about 20?), then what is the deeper reason for the VCC being prematurely dumped/short circuited?
Am I correct that these RFID Tags remain mute until they are asked (polled) to speak...unlike Cattle Tags...
Regards
Ray