output impedance measurement

hello

i built a small fm transmitter.pls tell me how to measure the output impedance of the oscillator stage inorder to match the antenna.

Ideally is to use a Network Analyzer.
If you don?t have something like this try to implement a variable L matching network (a trim-capacitor and a variable core inductor) tuned around the working frequency. Using a receiver on the other side, tune the antenna match for maximum received signal.