sabato 27 aprile 2019

Propagation News – 28 April 2019

Last week saw the start of the sporadic E season. There were reports of openings on 10m, and Andy, M0NKR even reported working The Gambia on 28MHz. This may have been a lucky F2-layer opening, but a contact is a contact!

Es signals from Czech Republic, Ukraine, Poland, Italy, Spain, and the French beacon F5ZEH beacon on 28.231MHz, were heard on Thursday, the 25th, at 1300UTC.

Don’t forget that sporadic E can affect all the bands from 20m to 10m. The best guide may be the 10m beacons across Europe, which can act as good propagation indicators.

We’ll look at Es a little more in the VHF section.

The solar flux level dropped below 70 last week as a result of sunspot number 2738 rotating off the visible disk. Sunspot 2739 never really amounted to much and since then the solar disk has been bare. One bit of news is that the cosmic ray flux has been increasing. This is to be expected as we head towards solar minimum.

Solar activity will remain very low, unless a sunspot crops up unannounced. A small coronal hole may cause some disruption on Friday or Saturday this weekend, just in time for International Marconi Day.

HF conditions remain challenging with even 20m not fully opening until later in the morning.

NOAA predicts the solar flux index will remain at about 60-70 this next week thanks to a spotless Sun. Geomagnetic conditions will be unsettled on the Saturday, the 27th, as we said, and again on the 30th, 1st and 2nd, when the Kp index may rise to four.

VHF and up:
We have a low pressure feel for many areas at first, so this spell of showery weather continues to provide a chance of rain scatter on the Gigahertz bands. The high pressure is only temporarily displaced, so as it rebuilds, to the north of Scotland in one model and to the south of Britain in another, there is clearly scope for changes to the forecast as the week progresses. Either way it does suggest that we may be able to talk of some tropo returning in the second half of the week.

The sporadic E season is upon us—and has been for some time using digital modes—and on Wednesday evening the 6m band gave a brief opening from the UK to Spain and the Balearics for SSB and CW. This seemed to tie in with a strong jet stream over the Pyrenees. From 1 May the daily Es blogs will restart on propquest.co.uk to give some ideas as to where to find these useful jet streams.

The forecast jet stream charts at the moment suggest that this region may migrate eastwards to affect the Alps before weakening and therefore paths towards Italy and the Balkans may be activated in the first part of the week.

After the excitement of the Lyrids meteor shower, this coming week will be a little slower. The Eta Aquarids shower will peak on 5 May, but there are meteors associated with the shower from around 19 April, so expect to see bursts and pings all this week.

The Moon will continue to wane this week with the New Moon appearing on 5 May. Libration will be at a minimum, but path loss will be quite high with the Moon coming off apogee—furthest distance from Earth—at the start of the week. The Moon will rise in the very early morning at the beginning of the week and with the low declination, it will set quite early. As the week progresses the Moon will set later in the day, making the later part of the week probably best for casual EME activity.