I'm trying to help a Plummer friend out. I was once a pretty good Navy Tech with good component level trouble shooting skills, but that is long in the past and I have forgotten all of the math required to figure out even the most simple circuits. He has a sewer camera with a locator for it. He has attached a small wire to the camera cable and the wire is connected to a 512 Hz generator called a locator, but it doesn't work under ground. I'm thinking that a tank circuit is needed to develop the signal near the camera head, but I cannot remember how to do the math to figure our what component values to use. I also think that the "wire" he used should be a pair so that I have a feedback path to the generator. This circuit also needs to be very small in size as it could get caught in the pipes and come loose, however it is very low power, so that shouldn't be a problem I think. Can anyone help me out here?