Propagation News – 13 June 2021

The predicted geomagnetic disturbance we spoke about last week didn’t amount to much. The Kp index rose to four on Monday evening, but the disturbance was short-lived and it was back to one later on Tuesday. Region 2829 was the only sunspot group visible on the Sun later in the week. This pushed the solar flux index to 80, but we are still a long way away from the kind of activity needed for real F2-layer DX.

The good news was a lack of coronal hole activity, which allowed the ionosphere to settle. This means that daytime maximum useable frequencies were often above 14MHz, but below 18MHz at times. Nightime critical frequencies are around 3.75-4MHz, which translates to a maximum usable frequency of around 10-13MHz over a 3,000km path.

The better news was that Sporadic-E continued to provide excitement on the upper HF band with many reports of single and double-hop openings.

The 10m UK Net group on Facebook reports that 7X2VFK in Algeria was workable on SSB, plus there were 28MHz openings to the US, Canada and the Caribbean.

Next week NOAA predicts more of the same with the SFI in the mid-70s, although regions 2824 and 2826 will rotate into view next week.

Geomagnetic activity should generally be settled, although we may expect a Kp index of four on or around the 16th due to a high-speed stream from a returning coronal hole.

VHF and up

It is going to be another summer mix for the coming week. Some periods of high pressure with summertime Tropo overnight and throughout the 24 hours across adjacent seas. There will also be some frontal activity with weather systems affecting northwestern areas and decaying into isolated showers as they move southeast into the high pressure.

This could mean that there are likely to be a few rain scatter opportunities again for the GHz bands. At present, the second half of next week looks a bit more unsettled with the possibility of thundery weather, especially in the south.

Sporadic-E has taken a bit of a pause lately or, at best, been rather ‘sporadic’ and the indications of jet stream patterns for next week suggests that favoured directions for openings will probably involve the UK across northern Europe and Scandinavia.

This northern positioning of the jet stream pattern may be what is needed for the more exotic paths across to the Far East via northern Russia. There may also be some valuable second hop possibilities across the Balkans and the eastern Mediterranean.

Basic rules are to check mid-morning and late afternoon and expect it to reach up to 144MHz if the conditions are favourable. The longest distances are often recorded at the start of a band opening so if you are working Es, remember to try the next higher frequency band.

With peak Moon declination passed, the week will feature shortening Moon visibility windows, lower peak elevation and falling losses as we approach perigee a week on Monday.

The Arietids meteor shower is declining now and the next one is the June Bootids peaking in a fortnight. This shower normally has a low ZHR of one or two, but has a reputation for outbursts of activity. The last being in 1998 when the ZHR hit 100. Until then, continue to look for the best random meteor scatter propagation around dawn.

Category: GB2RS Propagation News