I'm trying to determine the best method of measuring impedance from a wire through it's glass coating to determine if the thickness of the coating is correct. At the moment I do not have the actual frequency, I just know it is in the RF range and that my impedance needs to be 50 ohms. I've seen some people talking about putting a known load across the dielectric, but it doesn't make a lot of sense to me. If somebody could point me in the right direction (or explain the aforementioned load across the glass) it would be greatly appreciated! Thanks! EDIT: I do not have the ability to hook the wire up into the circuitry it will be used in (and seeing the RF power). I only have the wire.