Patent ID: 7835471

Claim:
A method for detecting a change in the operating characteristics of an installed power line carrier pick-up coil such that the pick-up coil is no longer exhibiting an expected resonant response comprising: selecting a test frequency for an alternating current test input where the selected test frequency is close to an expected resonant frequency for the pick-up coil such that a pick-up coil with an expected resonant response will provide a response in a first range of values to an input at this test frequency and a pick-up coil that is no longer exhibiting an expected resonant response will provide a response outside the first range of values in response to an input at this test frequency; defining the first range of values; testing, using a receiver, the pick-up coil by applying at least one test signal at the test frequency and measuring a response to the at least one test signal using at least some of components used in receiving data obtained by that installed power line pick-up coil; and comparing the response to the first range of values to discern whether the pick-up coil is no longer exhibiting an expected resonant response.