YouTube: Understanding HF Propagation

[VA3KOT John]

I came across a professionally made (Rohde & Schwartz) extremely well narrated 20-minute video called "Understanding HF Propagation". It is well worth watching even if you are an experienced HF operator. We all learned about ionospheric refraction during our Basic licensing course (for many of us that was a little while ago). This video also gives a clear explanation of Solar Flux Index, Sunspot Number, regional and planetary A & K indices and how they are measured. There's even a little bit of math for those of us who enjoy formulas.

Here is the video link: https://youtu.be/7Y_RTdPs3NI