domenica 30 settembre 2018

Propagation News – 30 September 2018

At the risk of sounding very samey, the solar flux index remained at around 67-68 with zero sunspots this week, and just a few points off what we can expect at absolute solar minimum.
As predicted, geomagnetic conditions were relatively poor at the beginning of the week, but did improve slightly later on, although the K-index remained at three at times. This was due to ongoing coronal hole activity on the Sun. But as we are now moving to better autumnal ionospheric conditions the daytime maximum usable frequency over a 3,000km path did exceed 18MHz at times according to the Chilton ionosonde. There are signs that if geomagnetic conditions can remain quiet for a few days this may even reach the dizzy heights of 21MHz. It is worth monitoring the higher bands, and if you don’t hear much activity, check out the FT8 frequencies on 18 or 21MHz or head for the International Beacon Network frequencies at 18.100MHz or 21.150MHz. If all else fails, call CQ!
Next week, NOAA predicts the solar flux index will remain around 68-70, but we may have unsettled geomagnetic conditions around 1 and 2 October 2018. The best HF conditions may occur later in the week as the ionosphere becomes more settled.

VHF and up propagation news:

At 21.47 on Tuesday, 25 September 2018, the Region 1, 144MHz tropo record was broken again, this time from England. G3SMT worked D4Z on the Cape Verde Islands via the marine duct caused by the Azores High system. At 4,431km, it broke the previous record of 4,270km set just one minute earlier by GW0KZG!
Next week has plenty of high pressure around, so get down to the bottom of the bands on CW, SSB and FT8. The high pressure will again be centred initially just to the west of the UK making linkage in to the Azores system still a possibility. Eventually part of this will drift east across the country to end the week over the continent, while a weak front crosses the British Isles. Tropo will be present to some degree for much of the week over southern parts, but more fleeting in the north, where it will be rather breezy at times.
If you’re not well placed for tropo, EME conditions will be at their best this coming week with peak declination on Tuesday and perigee next Saturday. Note that these two occurrences are starting to drift apart in time again, but don’t worry they won’t be fully out of phase until July 2022!

There are no significant meteor showers this week so around dawn on the lower VHF bands will be the best time for QSOs via random meteors.