Patent ID: 8013610

Claim:
A human-portable transmitter apparatus for generating an output signal having a frequency suitable for inducing an alternating electrical current in a buried conductor, the transmitter apparatus comprising: a User Interface (UI) for accepting operator commands; a controller coupled to the UI for selecting a desired output signal frequency value f R1 responsive to an operator command; an exciter circuit coupled to the controller for generating an excitation signal having a frequency corresponding to the desired output signal frequency value f R1 ; an electrical resonator coupled to the exciter circuit and having a primary resonant frequency to value f R , including a conductor assembly having an aggregate inductance value L, and a plurality of capacitors having an aggregate capacitance value C and disposed in connection with the conductor assembly to provide the primary resonant frequency value f R ; and and adaptive tuner coupled to the controller and the electrical resonator that adjusts the number of capacitors coupled to the conductor assembly responsive to the difference between the desired output signal frequency value f R1 and the primary resonant frequency value f R , thereby obtaining the capacitance value C necessary to produce a high Quality Factor (Q) output signal having the desired frequency value.