Foundations Of Amateur Radio

Foundations of Amateur Radio Recently I saw a social media post featuring a screenshot of some random website with pretty charts and indicators describing "current HF propagation". Aside from lacking a date, it helpfully included notations like "Solar Storm Imminent" and "Band Closed". It made me wonder, not for the first time, what the reliability of this type of notification is. Does it actually indicate what you might expect when you get on air to make noise, is it globally relevant, is the data valid or real-time? You get the idea. How do you determine the relationship between this pretty display and reality? Immediately the WSPR or Weak Signal Propagation Reporter database came to mind. It's a massive collection of signal reports capturing time, band, station and other parameters, one of which is the Signal To Noise ratio or SNR. If the number of sun spots, or a geomagnetic index change affected propagation, can we see an effect on the SNR? Although there's close on a million records per day, I'll