UK HF Propagation Prediction Maps

Steve Nichols G0KYA, chairman of the RSGB's Propagation Studies Committee, has updated his UK HF coverage prediction maps for this quarter using the current smoothed sunspot numbers (SSNs).


The maps for April to December can be used as being representative, but will be updated as and when the SSNs are updated later in the year.

Steve said that on the current evidence it looks like we passed the peak of Sunspot Cycle 24 in the Spring of 2014. However, the cycle still seems to have some life left in it.

The peak solar flux index (SFI) for the cycle occurred on 23 rd October 2014 at 227, although there were plenty of other times when it bettered 200, including January 2014, October and December 2014.

On an annual basis, 2014 had the highest average daily sunspot numbers of any year since 2002, according to the ARRL, although the peak solar flux indices were higher in 2002, hitting 261 on 29th January 2002.

The highest peak solar flux indices of cycle 23 were actually seen in 2001, with 283 being reached on 26 th September 2001. This cycle has been poor in comparison.

But what next? Steve says that what has been very apparent is the general increase in solar flares and coronal mass ejections (CMEs) recently. This has led to disturbed geomagnetic and HF conditions and is typical of the downward trail away from a sunspot maximum.

Over the next quarter we can expect to see overall sunspot numbers decline slightly, with solar flare and CME activity remaining high. Expect to see SFI numbers in the range 120-180, still good enough to provide good openings to DX on the higher bands at times.

We may see the cycle peak up yet again before it finally tails away, but are we likely to see the SFI go above 200 again? Who knows.

G0KYA's UK HF prediction maps - and his blog at