The Swedish Armed Forced are facing a period of growth. More military units in the size of batallions or brigades mean more radio systems that must share available resources, such as the number of frequencies. However, the frequency spectrum is limited and the radio systems within a brigade may need to share a common pool of frequencies. Frequency hopping is a well established technique to mitigate intentional jamming, but requires large bandwidths in order to provide sufficient protection. As many radio systems need to co-exist in the frequency domain within brigades that are geographically limited, interference from frequency collisions may not be avoidable. The impact on communication performance depends on a number of factors, such as the number of available frequencies, the number of communicating networks and the propagation conditions within the area. It is expected that several different types of frequency hopping radio systems, with different synchronization or hop rates, may share the same frequencies within a brigade. The main objective of this work is to analyze the performance of frequency hopping VHF-radio systems in a battalion subjected to interferences from the other VHFnetworks within a brigade with the assumption that all networks are always actively transmitting. The evaluation is performed using Monte Carlo-simulations, where the transmitter, receiver and interfererers are randomly positioned in a brigade area. The radio systems are generic and modelled using a number of parameters such as the number of frequency hops per packet, the number of available frequencies, the number of active networks per battalion and relative hop rates and time synchronization for the interfering systems. The results show that the packet error rate for a radio subjected to interference generally decreases as the number of frequencies increase, a greater number of frequency hops per packet is used, the average distance to interfering transmitters increases and if fewer number of networks per battalion are active. Moreover, the average packet error rate does not increase when the networks within a brigade are asynchronous, as opposed to when they are synchronous. When the radio systems use different hop rates, the packet error rate increases if the interfering radio systems use lower hop rates than the affected radio system. If the interfering radio systems use quicker hop rates, the packer error rate decreases. That is, if two frequency hopping radio systems utilize the same frequency space, the slowerhopping radio system is affected the least when they use the same frequency. At the longest communication range examined in the simulations (ca 4.5 km), the interfering transmitters must be at a distance of at least twice the communication range in order to provide packet error rates lower than 1%.