Measurement of Interference-to-Navigation/Communication Avionics from Cable Television (CATV) Systems.
Abstract
Airborne measurements of cable television (CATV) leakage were made at selected cities to compile a representative sampling of interference effects. Different altitudes were used in the flight-grid-type pattern. Ground measurements were also accomplished by the Federal Communications Commission (FCC) at the sites tested to determine any correlation between the ground and air measurements. The cities selected for discussion in this report were chosen to show various CATV effects detected by the data collection systems. A statistical analysis was performed on the data upon finding that direct airborne position correlation to strong ground leak points was not possible. The analysis is provided the mean for each of a grid and a comparison to determine if significant differences existed between runs. Where no significant differences were found, the condition was due to ambient noise exceeding signal level. Laboratory measurements were made to further confirm and define the interference of CATV leakage to VOR receivers. Recommendations include maximum signal level for CATV cable leakage that may be tolerated in the communication and navigation bands. A further recommendation was made that the CATV industry use frequencies in the navigation band which are separated from Federal Aviation Administration (FAA) navigation frequencies by 25 kilohertz. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1979
- Accession Number
- ADA081430
Entities
People
- Edward M. Sawtelle
- James G. Dong