Study of Electromagnetic Interference from Power Lines on AM Radio Reception in Kaduna State

Electromagnetic interference from high-voltage power transmission lines degrades the quality of amplitude modulation radio reception in rural and peri-urban communities that depend on AM radio for public information access. In Kaduna State, North West Nigeria, several communities are situated within close proximity to 132 kV and 330 kV transmission line corridors. This study investigates the extent and spatial pattern of electromagnetic interference from power lines on AM radio reception at frequencies between 540 and 1600 kHz across three communities along the Shiroro-Kaduna 330 kV transmission line corridor. A calibrated spectrum analyser connected to a loop antenna is used to measure the noise floor level at AM broadcast frequencies at 100-metre intervals perpendicular to the transmission line from 50 to 1,000 metres. Electric field strength from the line is concurrently measured using a field strength meter. Results indicate a power-law decrease in EMI noise level with distance, with significant interference extending to 400 metres from the line centre at 630 kHz. The study recommends a minimum separation of 500 metres between transmission line corridors and AM broadcast reception zones in rural planning guidelines for Kaduna State. Keywords: electromagnetic interference, power line, AM radio, Kaduna State, noise level