Addressing the distance limitation of conventional single-mode propagation in VHF Band, this research systematically studies the communication channel resources within the VHF band, including ground-wave diffraction and tropospheric scatter propagation.Given the complexity of VHF OTH propagation modes, a method for distinguishing between different propagation modes is proposed through a combination of theoretical analysis and statistical analysis of extensive field channel measurements and communication test data. Drawing reference from the channel characteristics of C-band tropospheric scatter communication, the study provides both slow-fading characteristics (such as diurnal and annual variations) and fast-fading characteristics (including fading depth, fading rate, and fading duration). These findings offer crucial support for VHF OTH communication waveform design.Based on the channel characteristics observed at different distances and across various seasons, this paper proposes a design approach for VHF OTH communication systems. The aim is to more effectively utilizing the diffraction and scatter communication resources available in the VHF band for OTH links. This approach supports the enhancement of coverage range and communication capabilities for VHF band communication equipment.