# Radio Channel Modelling for VHF System Operating in the Offshore Wind Farms Propagation Environment
## 4 Conclusions
On the other hand, if we are aware of that and if we determine the relevant \"corrective coefficients\" (in this case: 15 dB for Anne 1 and 9 dB for Anne 2), than the ITU-R BT.1893-1 model can well be utilized to assess the offshore wind turbines impact on maritime VHF radio systems. During the study described in the paper, the authors also analyzed the Doppler power spectra density. On the basis of the collected and analyzed measurement data, it should be stated that recommendation ITU-R BT.1893-1 faithfully illustrates the shape of the Doppler power spectra density. For the existing measurement conditions, it is stated that for frequencies from about \(-\)10 to +10 Hz the best representation is the low variability version of the Doppler spectrum, while outside this range the best approximation is the high variability version. On the basis of the measurements and their comparison with the theoretical results, knowledge was gained regarding the situations for which it is most advisable to use a given model from the ITU-R BT.1893-1 recommendation. Based on this, it was possible to simulate selected radio channel parameters for ship systems in the marine environment. As a result it was possible to obtain accurate received signal power level and Carrier to Interference Ratio (CIR) values, for different offshore wind farm configurations. These parameters show exactly what coverage can be expected in the selected area and whether there is a need for corrective actions to improve radiocommunication quality in this area. An offshore verification campaign is planned in the future to confirm all assumptions discussed in this article. The paper dealt with the offshore wind farms' impact analysis of the radio systems operating in the maritime VHF band. We should realize that, while VHF is the major maritime frequency range, there are other bands and systems relevant to this topic as well. This includes--among others--the UHF band, radar systems, radionavigation, specific military solutions, etc. In most cases, those area will also have to be addressed while evaluating the impact of the future wind farms. That requires appropriate mathematical and theoretical background, building necessary tools (e.g., for simulations), and gaining full knowledge about the analyses systems. These factors are obviously beyond the scope of this article, but at the same time, they also show how complicated, multi-faceted, and important these issues are for the overall development of the wind energy at sea. **Author Contributions:** Conceptualization, K.B., A.L. and B.W. ; methodology, K.B. and A.L. ; software, K.B., R.N. and P.K; validation, R.N., P.K. and B.W. ; investigation, K.B., R.N. and B.W. ; data curation, P.K. and A.L. ; writing--original draft preparation, B.W. and P.K. ; writing--review and editing, K.B. and A.L. ; visualization, R.N., P.K. and B.W. ; supervision, K.B. All authors have read and agreed to the published version of the manuscript. **Funding:** This statutory work (number 08300013) was partially funded by the Polish Ministry of Education and Science. **Data Availability Statement:** All collected measurement data and simulation results analyzed during the current study are available from the corresponding author on reasonable request. **Conflicts of Interest:** The authors declare no conflict of interest.