Propagation News – 14 May 2017

Last week the solar surface was pretty much bare, other than a tiny speck of a sunspot at mid latitude. This sent the solar flux index down below 70 – the first time it has been there for some time. Given that it never drops much below about 66, even at sunspot minimum, this gives you an idea of how little sunspot activity there is. Luckily, the low solar flux index was coupled with better geomagnetic conditions, with the K index never worse than three and often zero.

The more settled conditions meant the ionosphere had time to recover and there was DX to be had. Dick, GU4CHY reported he worked all continents, including many strong Japanese stations, on 20m around 2030UTC on the 10th. Don’t forget that 20 metres will be staying open longer as we head into summer, and the band may even remain open late into the night by June and July.

Next week NOAA predicts the solar flux index will increase, perhaps up 80. Unfortunately, this will be accompanied by poor geomagnetic conditions at times due to the return of a recurrent coronal hole. The K index could rise to four or five midweek.

Sporadic-E may offer some respite. Don’t forget that it can affect all HF bands, not just 28MHz. Martin, MW0CND in Swansea was very loud in East Anglia last week on 40m CW during daytime on an otherwise flat band as a Sporadic-E cloud formed over the UK.

It looks like a week of unsettled weather is coming up as we had some locally heavy rainfall at the end of last week, extending into this weekend. But as we progress through the week high pressure begins to appear, initially in the south of Britain.

As next week draws to a close, the trend in several models is for a larger high to develop west of Ireland and slowly move east to be over the country by the weekend. Therefore, there is an increasing chance of Tropo developing later in the week.

Sporadic-E deserves a mention too, since there have been some openings already and now through to August represents good hunting for those elusive QSOs on 10m, 6m, 4m and 2m. Check the beacons and clusters as usual, with late morning and late afternoon being the best times.

This is a good VHF/UHF set of options for most regions this next week, although typically the far north of Scotland does seem to be on the northern fringe of any Tropo.

Moon declination is negative all this week, so there are short moon windows for EME. Last Friday the moon was at apogee – its furthest point away from Earth – so losses are still high, but falling as the week progresses.

And that’s all from the propagation team this week.

Category: GB2RS Propagation News