The distance to Europe from your location is approximately 5000 km. What type of high frequency (HF) propagation is the most likely to work?

To communicate over a distance of 5000 km on the high frequency (HF) bands, your signal will almost certainly rely on multi-hop propagation. A single hop via the highest ionospheric layer (the F2 layer) has a maximum theoretical distance of about 4000 km due to the curvature of the Earth and the height of the layer. Because 5000 km exceeds this single-hop limit, the radio wave must refract back to Earth, bounce off the surface (or ocean), and travel back up to the ionosphere for a second hop to reach its destination. Other propagation types listed are unsuitable for this range. Tropospheric scatter and Sporadic E are generally VHF/UHF phenomena limited to much shorter distances (typically up to 800 km and 2000 km respectively), and back scatter produces weak, localized signals rather than reliable long-distance communication.