The Murphy's Law of RF transmission in a shielded unbalanced cable states that: 1) Signal will leak out 2) Signal will leak in Signal leakage from CATV systems has always been a problem. However, prior to the general use of mid-band and super-band channels, our concerns were usually based on interference to the non-subscriber's television reception. the Harrisburg, PA incident of 1976 reminded us of the real possibility for hazardous interference to aircraft communications and navigation. The Cable Television industry was forced to take the issue of Signal Leakage more seriously.