Propagation News – 17 December 2017

| December 15, 2017

Last week, the solar flux index nudged into the low 70s, although the Sun remained spotless. The enhanced solar wind from a coronal hole pushed the K-index to four, and it remained around three for long periods during the week. So these were far from ideal conditions for F2 layer DX on the higher bands, but there were good openings to be had.

Last weekend’s ARRL 10 metre contest benefited from some extended sporadic E openings around Europe. The openings were possibly caused by strong jet stream activity over central and northern Europe. This is a reminder that it is worth checking 10 metres now and again to see if the band is open. Others have reported good mid to late-afternoon openings on 40 metres, with Australasia and the Pacific being worked at times. This is classic mid-winter propagation and it is worth looking out for.

Next week NOAA predicts the solar flux index will remain in the low to mid-70s. Another Earth-facing coronal hole on the Sun’s equator on Thursday will no doubt result in a high-speed solar wind stream. NOAA predicts this has the potential to push the K-index up to five this weekend and Monday, with the possibility of depressed maximum usable frequencies and auroral conditions. The K-index may settle again from Tuesday onwards. So the best advice is to concentrate on the long winter nights, with 40m possibly opening up from late afternoon and the potential for DX on 160, 80 and 40m through the night and at sunrise.

VHF and up

After a cold end to the week, there will be a marked change as high pressure returns across the southern half of Britain during this weekend. Much of the country will have good conditions and the chance of fairly widespread tropo at times during next week. The models are in agreement in developing a large high over Biscay, which could go on to produce lift conditions over the southern half of the UK and much of the continent. Windier conditions over northern areas will limit the tropo activity over Scotland, but even here some enhancement of conditions is possible at times.

With the Geminids shower peak now over, we revert to more normal meteor scatter conditions until the January Quadrantids, with early mornings continuing to be the best time for making QSOs.

With Moon apogee and minimum declination on Tuesday, EME opportunities will be short and path losses high, so maybe it’s a good week to make some pre-Christmas QSOs using the various artificial satellites at our disposal.

Category: GB2RS Propagation News