venerdì 26 gennaio 2018

Propagation News – 28 January 2018

News last week that the Republic of Kosovo (Z6) has been added to the DXCC list of current entities meant that QSOs with the new prefix were in demand. With Z60A on the air from Pristina until 4 February, there has been a sudden interest in propagation paths to the country! VOACAP Online shows that Z60A should be a fairly easy catch from the UK propagation-wise, although the massive pile-ups are causing problems. At around 2,000km from central UK, 30, 20 and 17 metres are the favourite bands to contact Z6 during daytime, with a 90 to 100 percent probability of a propagation path at times. This falls to 70 to 80 percent on 15 metres. At night, 80 and 40m come into their own, with again a more than 90 percent chance of a good path.These all depend upon having settled geomagnetic conditions, which were once again badly affected last week by the solar wind from a coronal hole on the Sun.

The K-index rose to four on Wednesday evening, as a result of the Bz component of the interplanetary magnetic field (IMF) pointing south, enabling the solar wind to more easily couple with the Earth’s magnetic field. Next week NOAA forecasts that the solar flux index will be in the range 67-70 and we may expect more unsettled geomagnetic conditions on Sunday, the 28th. The rest of the week is predicted to be more settled.

At the moment, daytime maximum usable frequencies over a 3,000km path are most reliable on 20 metres, with occasional openings on 17 and 15 metres.

VHF and up:

The windy weather of recent days caused the really poor tropo conditions during last week’s SHF UK activity contest, but it is probably behind us for a while. A mild southwesterly flow from the Atlantic can sometimes provide enhanced tropo conditions, especially if it is accompanied by a region of high pressure nearby, over the continent. This is a distinct possibility later this weekend as high pressure builds across France and into Germany. The slightly ‘lifted’ conditions, chiefly in the south, developing over this weekend will probably last until a cold front arrives on Monday night.

The mid-week period sees low pressure to the east of Britain with a colder northerly flow and a return of flatter conditions, although there could be some rain scatter to the east over the North Sea on the microwave bands.

The last part of the week is split between high pressure building again over southern areas towards next weekend, and other models keeping the colder showery northerly option.

Random meteor rates are low this time of year and there are no showers due until the Lyrids shower at the end of April.

The Moon is approaching perigee and is its closest to Earth on Tuesday. Its declination reaches maximum on Monday, so there should be good EME conditions all this week.