This study presents a new practical measurement method for analyzing narrowband wireless mesh networks (NWMNs) application performance. It investigates a scenario for packet transmissions in NWMNs, leveraging wireless interconnection between two devices. It analyzes the effect of message size and channel spacing on the resulting bitrate, forwarding time and modulation rate through experimental results. We transmit a single packet for one hop, exploiting a versatile radio modem with very-high-frequency radios operating in the bridging or routing modes. The measurement results obtained, with the mentioned critical operating parameters, provide a quicker and clearer idea as well as conclusive evidence for overall network performance.