The Swedish Armed Forces are currently undergoing a period of growth, with the Army being expanded with several brigades, the Navy planning for new surface vessels, and several platforms being modernized. The need for wireless communications will therefore increase, but the available frequency spectrum will not. With a growing defense force, it is not possible to allocate frequencies to all radio systems without conflicts, which means that spectrum sharing is necessary. It is therefore very important that the available frequency spectrum is used as efficiently as possible by radio systems in order to achieve robustness and availability. Shared use of frequencies can lead to impaired performance due to frequency conflicts if no measures are taken. The consequences of frequency conflicts and methods for reducing the impact of these conflicts have been studied in this report. The report summarizes the activities and results of the R&D project Flexible Frequency Use for the Swedish Armed Forces' Radio Systems during 2023-2025. The project's results have also been disseminated through an annual workshop with participants from FOI, the Swedish Armed Forces, FMV and FRA. The workshop has contributed to increasing the availability of research results, but also to dialogue between researchers and clients regarding their challenges and knowledge needs. Frequency conflicts for a battalion network have been evaluated in scenarios where the brigade area and the number of frequencies vary. Using fewer frequencies results in a higher packet error rate. Radio networks with higher hopping rates are more affected by frequency conflicts from radio networks with lower hopping rates than vice versa. In certain situations, frequency allocation needs to be adjusted to counteract destructive interference. Power control has been studied as a method for reducing the consequences of frequency conflicts, improving stealth capabilities, and reducing energy consumption. The study shows that the output power can be reduced while maintaining the packet error rate within the radio network. The reduced output power also means that signal interceptor must come closer to the transmitter to maintain their detection probability. One way to avoid interference caused by frequency conflicts is to flexibly divide available frequencies between radio networks. Methods for determining when and how frequencies should be allocated between radio networks have been studied. The results show that the proportion of packets that can be sent in a radio network with many packet losses can increase, at the expense of the proportion of packets that can be sent by the other radio network. The advantage is that both radio networks achieve more equal performance. The method needs to be developed and evaluated for scenarios with more radio networks, nodes, and frequencies. Anelectromagnetic environment situational awareness is necessary in order to share spectrum to a greater extent. How an electromagnetic environment situational awareness should be created, stored, protected, distributed, and visualized requires further work.