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
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