Technical Analysis of Frequency, Receiver Sensitivity and Site Suitability for Amateur Radio VHF Repeater Deployment

Abstract

This study presents a technical analysis of frequency suitability, downlink receiver sensitivity, and site suitability for a proposed local VHF amateur radio repeater deployment in Bandar Maharani, Muar, Johor, Malaysia. The proposed repeater operates at 146.900 MHz downlink and 146.300 MHz uplink with a −0.6 MHz offset and 203.5 Hz CTCSS tone. The repeater is planned for installation at Wisma Daim, where the Muar District Amateur Radio Association has office access and permission to install the antenna system on the rooftop. The study evaluates frequency compatibility through nearby VHF channel separation, local coverage prediction using FSPL baseline and adjusted ITU-R P.1546 analysis, and downlink receiver sensitivity margin using the Baofeng UV-5RE as a worst-case handheld receiver reference. The findings indicate that the proposed 146.900 MHz output channel provides acceptable preliminary spectral clearance. At the same time, the Wisma Daim rooftop site is technically reasonable for local communication coverage within Bandar Maharani, the Muar town area, and nearby mukim. The downlink sensitivity assessment also shows that the predicted signal level remains above the minimum receiver sensitivity threshold under planning assumptions. Overall, this study provides structured technical evidence to support repeater planning and application, while recommending post-installation spectrum monitoring, drive testing, and receiver verification before full operational use.