Measurement of the APD and the Degradation Caused by Power Line Noise at HF.
Abstract
Measurements of electromagnetic noise from power lines were made by Stanford Research Institute (SRI) in direct support of the Electromagnetic Compatibility Analysis Center (ECAC) in their work in the Naval Electronic Systems Command (NAVELEX) man-made radio noise program. Tests were conducted at 3 MHz in the late spring of 1975 in the vicinity of three power transmission lines (two at 230-kv) expected to be sources of corona noise and three low-voltage power distribution lines expected to be sources of gap noise. The power-line noise was used to degrade the performance of a binary FSK modem (AN/URA-17). Simultaneously, the amplitude probability distribution (APD) of the noise envelope was measured in three bandwidths, and in the unused channel of the URA-17, using specially developed instrumentation and software. This instrumentation samples and digitizes the noise envelope from each receiver at a rate of 200 samples per second and records these samples on magnetic tape. A computer processes the noise samples to calculate the rms noise voltage, (which is convertible to the effective antenna noise factor Fa) , the parameter Vd, and the APD. The Vrms and Vd measurements were compared with those from a Singer NM-26T reciver. Photographs of both gap and corona noise envelope voltage were made in several bandwidths. Corona noise measurements were made in weather conditions ranging from no-rain to heavy rain. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1976
- Accession Number
- ADA047681
Entities
People
- James C. Gaddie
- Richard A. Shepherd
Organizations
- SRI International