HF Radio Propagation
Predictions
and Space Weather

HF radio
propagation predictions based on the „ITU method“
(ITUR P.53311) must be calculated using the 13month
sliding average SIDC Sunspot number (formerly called the Zurich Sunspot
number). The reason is that the original theory and underlying data in the
ITU predictions are based on exactly this number and thus alternative
measures of the solar activity (actual sunspot numbers, Boulder Sunspot
numbers, solar flux, etc.) will not yield correct results. On the
bottom of this page regularly updated predictions of the Sunspot Numbers can
be downloaded. It
must be remembered that the predictions are monthly medians, i.e.
on 15 days of the month “conditions“ will be better and on
the remaining 15 days “conditions“ will be worse than predicted.`
