Propagation News – 31 May 2020

This last week was dominated by a quiet Sun, but extensive sporadic E openings. We had a solar flux index hovering around 70 and zero sunspots, nevertheless we have had good F2-layer propagation on HF and multi-hop sporadic E bringing DX excitement.

Last weekend saw FT8 openings on 10 metres to the Caribbean and South America, even after sunset. Laurie, G3UML reports working KL7KK in Alaska and KH6YY in Hawaii on 20m SSB, which just goes to show that you shouldn’t write off HF just because of a low sunspot number! Laurie said: “There’s been quite a bit of Pacific activity on 20m in the mornings and lots of Gs working it. Jim, E51JD on the South Cook Islands was a readable five and five this morning.”

The Sun is showing some signs of life. An active region approaching the north-east limb just produced a minor solar flare that may be associated with a coronal mass ejection (CME). The minor event registered as a long duration B-class solar flare.

An image from the STEREO Ahead spacecraft reveals a wave spreading across the far side of the Sun, which can be indicative of a CME. But because of its position it should be directed completely away from Earth.

A small coronal hole was facing Earth on Thursday, which could mean a minor solar wind influence may be expected this weekend. A possible sunspot belonging to Cycle 25 may also begin to turn into view.

NOAA predicts the SFI will remain at or around 70 all week with a maximum Kp index of two. Sporadic E conditions should continue, providing short-skip openings on the higher HF bands.

VHF and up

The long period of high pressure weather is going to hang on, with some good tropo opportunities, just through this weekend. Apart from a small hint of an isolated shower over this weekend, most places will stay dry until the middle part of next week.

On Tuesday a weakness in the high will allow isolated, but potentially heavy showers to develop, with a chance of rain scatter. This shower risk then stays with us through the rest of the week, but always on the edge of high pressure to the east and west of Britain.

In the second half of the week a cooler northerly flow will bring an increased shower risk, some heavy and thundery, but confined to the south by the following weekend.

The sporadic E prospects are usually at a peak around the early part of June, so expect to hear some of this fleeting, exotic propagation mode on the bands from 10m up to 2m. If the skip gets shorter, say strong DLs on 10m, then check 6m and so on, up to 2m for a really good opening.

Lots of factors influence its likelihood, but the best practice is to listen late morning and late afternoon or early evening. Check Propquest for daily blogs on possible sporadic E hotspots.

Moon declination goes negative on Monday, but we are at perigee on Wednesday, so EME path losses are at their lowest. 144MHz sky noise is low until Friday and Saturday but as peak Moon elevation is low, ground noise will dominate.

June continues to be an active time for meteor scatter operations, and the daytime Areitids shower peaks on the 7th.

Category: GB2RS Propagation News