Basic Signal Leakage Performance Report (FORM 320)

FCC Form 320 contains a snapshot of the interference potential to aircraft communications and navigation over a cable system's distribution plant. Cable operators have the option of performing either the ground based CLI (10 log I or 10 log I3000) or airspace measurement, in either case the test result should show compliance with the basic signal leakage criteria outlined in 47 CFR Section 76.611. The test equipment used must be capable of measuring leaks of 20 µv/m @ 3 meters or its equivalent, and the test frequency must be within the VHF aeronautical band of 108-137 MHz or a frequency in which the results can be correlated to that band. The test signal used shall carry an average power equal to the average power level of the strongest carrier on the system. The accompanying exhibits shall include a list of all aeronautical frequencies used (Exhibit A) and information on the test measurements including a list of all leaks 50µv/m or greater detected for ground based measurements, (Exhibit B) or information on airspace tests (Exhibit C).

If you have any questions about the Form 320, please call (202) 418-7000.

     Commonly Asked CLI and Form 320 Questions
     Click Here for On-Line CLI Calculations
     Click Here for to file Form 320 electronically