ARLA/CLUSTER: UK HF Propagation Prediction maps

[João Costa > CT1FBF]

Steve 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 29 th 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.

You can see G0KYA's UK HF prediction maps at
http://www.infotechcomms.net/propcharts/ and his blog at
www.g0kya.blogspot.co.uk

• All propagation reports can be found at:
http://www.southgatearc.org/propagation