venerdì 18 giugno 2021

Propagation News – 20 June 2021

A large coronal hole returned last week and started to become Earth-facing on Monday the 14th. The high-speed solar wind stream from the hole impacted the Earth on Tuesday evening, pushing the Kp index to five. Luckily, conditions returned to normal by late Wednesday and the Kp index was down to two or three thereafter. It now looks like we are free of coronal hole effects for the time being.

Sunspot-wise, region 2833 put in an appearance. Its effects on the ionosphere have been minimal with the solar flux index stuck at 76 on Thursday the 27th and the sunspot number at 11, representing one spot in one group.

HF propagation has been adequate rather than outstanding, with the real talking point remaining Sporadic-E. Conditions on 10 metres have been good with long, solid openings to Europe popping up each day. Do make the most of these, as F2-layer openings on 10m may be harder to find once the Sporadic-E season ends.

Next week NOAA has the SFI at around 80 and quiet geomagnetic conditions with a Kp index of two. We are still not seeing the ramp-up in sunspot activity that we would like, although fingers are crossed that this Autumn might be more positive.

In the meantime, make the most of the Sporadic-E openings, particularly on the higher bands such as 12 and 10 metres. These openings can affect lower HF bands too, although it is sometimes hard to distinguish them from F2-layer openings.

So please don’t ignore 15 metres and lower at this time and look for short-skip contacts on these bands as well.

VHF and up:

It looks like the majority of next week will see low pressure predominating with further periods of unsettled and potentially thundery weather. The pattern places the main area of low pressure over or just west of the UK, forcing a thundery showery southerly flow across the country. There will be some interludes when brief ridges of high pressure show up, especially in southeastern areas, but overall Tropo will not be high on the list. So, apart from some rain scatter prospects and the occasional extended sea path Tropo across the North Sea or English Channel, it will mostly be a week for chasing Sporadic-E.

The northern part of Europe and Scandinavia have a good jet stream flow and this extends into northern Russia, making it worth checking those DX paths into the Far East and Japan. The other region looking well favoured with jet stream patterns is to the south into Spain and Portugal.

We are in peak season for Sporadic-E, so keeping a regular routine of checking the bands mid-morning and early evening is the best procedure to follow.

The Moon is at perigee on Wednesday so path losses will be at their lowest. Sadly, with minimum Moon declination on Friday, visibility windows and peak Moon elevations will also be at their shortest and lowest of the month.

The June Bootids meteor shower peaks on Sunday 27th. This shower, although normally small, has a reputation for outbursts of activity. Until then, continue to look for the best random meteor scatter propagation around dawn. (