This paper evaluates the efficiency of IP packets transmission in narrowband networks based on the RRC 9310AP tactical radios. BER characteristics vs. distance for a rural environment was determined and statistics of errors distribution in VHF channel were presented. We also found the thresholds of BER, when the data rate of the radio interface changes automatically according to the channel conditions. Based on measurements performed in a real environment, we examined the user throughput for selected length of UDP datagrams. We mapped the BER to the data rate of the radio interface. Finally, we found that the maximum throughput offered to the user in IP-PAS mode amounts up to 9 kbit/s. Based on these results, we assessed the efficiency of the RRC 9310AP tactical radios in the IP-mode.