Phase noise of local oscillators in frequency converters in an FM Video link can introduce noise into TV pictures in a CATV system. The acceptable level of such noise have not been established. The qualitative measure of phase noise is its perceptibility in a TV picture. Baseband signal-to- noise ratio (SNR) is a quantitative measure. This paper presents the theory relating the RF noise spectrum of an oscillator and the baseband noise spectrum and SNR for an FM Video link. Measured results are compared to the theory and conclusions about perceptibility presented.