Monday, 5 January 2015

UK HF Propagation Prediction maps

I have now updated my 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.

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 23rd October 2014 with 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 26th September 2001. This cycle has been poor in comparison.

But what next? 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.

You can see my UK HF prediction maps at or use the link top right.


  1. It's all good stuff, but it is not wise to be constrained by 'predictions', or to base your activity upon such. Apparently 'dead' bands - often made deader by herds following predictions and others' activity - often yield good DX. It's better simply to take each day - and each hour - as it comes.

    "Never say never", might be a useful thing to remember...

  2. You are, of course, absolutely right. The maps are a guide really, but you always get the odd surprise. They also "average" out the month, so some days will be better than others.