Code of Federal Regulations Title 47. Telecommunication § 47.76.616 Operation near certain aeronautical and marine emergency radio frequencies

(a) The transmission of carriers or other signal components capable of delivering peak power levels equal to or greater than 10^-5 watts at any point in a cable television system is prohibited within 100 kHz of the frequency 121.5 MHz, and is prohibited within 50 kHz of the two frequencies 156.8 MHz and 243.0 MHz.

(b) At any point on a cable system from 405.925 MHz to 406.176 MHz analog transmissions are prohibited from delivering peak power levels equal to or greater than 10^-5 watts. The transmission of digital signals in this range is limited to power levels measured using a root-mean-square detector of less than 10^-5 watts in any 30 kHz bandwidth over any 2.5 millisecond interval.