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Propagation News – 9 May 2021

The Sun was devoid of sunspots last week, which saw the solar flux index plummet to 70 – pretty much what it is around sunspot minimum. The good news is that an active region is rotating into view. Region 2817 is currently just on the Sun’s eastern limb as this report is being prepared and should be visible by the time the weekend is here. On its last rotation, the region was quite active and pushed the SFI up to 86, so the hope is that we get a similar surge when it reappears.

Geomagnetically, the Sun has been quite quiet with the Kp index at either one or zero last week. This has been boosted by a lack of coronal hole activity. HF-wise, it has been fair but not outstanding, which is in line with what you would expect with an SFI of 70.

Most of the chat has been about the beginning of the Sporadic-E season, which has seen a few openings to Spain and Italy. The 10 metre beacons IZ1EPM on 28.173MHz near Turin, Italy and ED4YAK on 28.251MHz in Henares, Spain were heard on Wednesday. For a complete list of low power 10m beacons please see G3USF’s list via the Propagation pages on RSGB.org.

Tony, G4CJC’s 10 metre report says Joe, G3ZDF worked KP4JRS, HC2TIC, CT1BFP and heard PJ2BR, KG4IYS and CO3JR on FT8 after 11pm. This was probably via multi-hop Sporadic-E rather than F-layer propagation. There have also been one or two reports of long-distance FT8 contacts on 10m from the Far East, which may be due to short-path Summer Solstice Propagation.

As the Sporadic-E season progresses we can expect to see a lot more activity on 10 metres.

Next week NOAA predicts the solar flux index will climb to the high 70s, no doubt boosted by region 2817. Geomagnetic activity is predicted to be quiet for the first half of the week, but could turn unsettled on the 11th with the potential for the Kp index to reach five or six by the 14th with the return of a large solar coronal hole. Expect subdued MUFs until the Kp index recovers.

VHF and up:

There is a predominance of low pressure on the charts for much of the next week and more active systems will mean some heavy rain and strong winds for some areas. The models diverge towards the end of next week, with one version showing high pressure over northern areas by the end of the week, while the other option shows a continuation of low pressure.

The outcome of this is a mainly rain-scatter week for the GHz bands and at this time of year showers are often heavy and thunderous, which can be very good scatter sources. The option of high pressure at the end of next week may herald some Tropo in the north.

Sporadic-E is building nicely and most days will offer the prospects of some Sporadic-E, especially on the digital modes or 10m. There will be some well-placed jet streams in attendance next week, so keep an ear on the bands and beacons.

With positive Moon declination, we’ll see lengthening Moon visibility windows and peak Moon elevations as the week goes on. The Sun and the Moon will be at apogee and close to eclipse on Tuesday, meaning highest path losses and very high noise levels after lunchtime.

There are no significant meteor showers this week but we will still be in the tail end of last week’s Eta-Aquarids so look out for continuing random activity. (rsgb.org)

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