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

Abstract

Reliable local radio communication requires compatible frequency allocation, sufficient receiver sensitivity, and a suitable repeater installation site. However, the deployment of a VHF amateur radio repeater requires systematic evaluation of spectral compatibility and link feasibility to minimise interference and ensure satisfactory communication coverage. This study evaluates the technical feasibility of a proposed stand-alone local VHF amateur radio repeater at Wisma Daim, Bandar Maharani, Muar, Johor, Malaysia. The deployment is intended to improve local communication reliability, but its proposed channel, predicted coverage, receiver performance and rooftop configuration require an integrated assessment before regulatory application and installation. The system uses MCMC channel RV87, comprising 146.900 MHz downlink and 146.300 MHz uplink, a −0.600 MHz offset, and a 203.5 Hz continuous tone-coded squelch system (CTCSS). A five-phase assessment covering system baseline definition, spectral-clearance and QRM screening, FSPL and P.1546-referenced suburban coverage estimation, receiver-sensitivity benchmarking, and a weighted site-suitability evaluation was conducted. The proposed channel had a minimum separation of 75 kHz from the closest identified VHF channel with no channel conflict in the study dataset. The author-defined 52 dBµV/m planning threshold was reached at approximately 29.1 km by the suburban planning curve. At 146.900 MHz, this field strength corresponds to approximately −68.5 dBm for a 0 dBi receiving antenna, producing a 52.5 dB reference-threshold-to-sensitivity headroom relative to the Baofeng UV-5RE specification of approximately −121 dBm at 12 dB SINAD. The site achieved a suitability score of 8/10 (80%), which indicates that the Wisma Daim site is suitable for the preliminary planning stage. These findings support proceeding to formal frequency coordination and controlled installation, subject to spectrum monitoring, TX/RX isolation testing, SINAD measurements and a post-installation drive test.