A radio frequency ID tag, very small in size and with an onboard antenna, is manufactured, tested and applied cost-efficiently. The transmit frequency for the tag is set during manufacture approximately, within a selected range, in a gross tuning step. A second tuning step fine tunes each tag by RF communication to set values of capacitance, resistance, etc., and this can be at the point of application of the tags. Other aspects include burning a randomly-selected value in the RF ID chip during manufacture to impose a random time delay for tag response (rather than having a random generator on the chip itself); structural testing of a large number of tags on a wafer using on-wafer interconnects and a special onboard sequencer test die; and production of the tag so as to be tunable to different frequency ranges.