The method is very simple. You simply observe how far apart in frequency the repeating gyrations in impedance are, and use standard 1/2 wave formulas to convert the difference frequency to distance.
I can do this with a low power VFO and a diode detector or scope. It does not even have to be a bridge. :)
73 Tom
_________________ Topband Reflector Archives - http://www.contesting.com/_topband