venerdì 14 ottobre 2016

Propagation News – 16 October 2016

The solar flux hovered around the 100 mark and, as predicted, HF propagation showed a big improvement earlier in the week thanks to more settled geomagnetic conditions. There were many reports of DX being worked from the UK including H40GC in Temotu, Solomon Islands, and T31T in Central Kiribati.

The Kp-index was in the range one to three up until Wednesday, but then hit five on Thursday, due to incoming plasma from a coronal mass ejection that took place on 9 October. The initial positive phase of this disturbance saw good 10 metre F2 layer propagation on Thursday, with Kuwait, Bahrain, Puerto Rico and Chile easily workable. There was also evidence of 10 metre sporadic E on Wednesday and early Thursday with low power beacons romping in from France, Spain, Austria and Italy.

Next week NOAA predicts the solar flux index will decline slowly to 85 by Saturday the 22nd. The weekend will then be very unsettled geomagnetically with a Kp-index of up to five. The second half of the week may be more settled before the onslaught of higher Kp numbers again across the weekend of Saturday 22nd and Sunday 23rd. Midweek may therefore be best with more settled geomagnetic conditions and the chance of DX contacts up to 21MHz or even higher. With the longer autumn nights the low bands are also starting to come into their own.

VHF and up propagation:

It’s a rain scatter start to the coming week with a continuation of the unsettled showery weather and a trough of low pressure over the country. Gigahertz bands enthusiasts should be on the lookout for short rain scatter openings in the showers. From about the middle of the week, pressure will rise as an area of high pressure builds in from the west, offering the chance of some weak tropo conditions. That said, there is some uncertainty as to whether the new high favours southern or northern Britain.
We’re currently passing through the stream of debris left behind by Comet Halley, the parent comet of the Orionids meteor shower. The shower is expected to peak before dawn on Friday the 21st, so look for a peak in meteor bursts on the lower VHF bands.

It’s a good week for EME with increasing moon declination giving long moon windows. The Moon reaches perigee, its closest point to the earth, this evening Sunday 16th, so EME path losses are at their lowest this week.