Propagation News – 16 June 2019
We had another quite settled week. The Kp index rose to four on the 8th thanks to a glancing blow from an earlier coronal mass ejection. It rose to three again on Thursday the 13th due to an enhanced solar wind stream. The solar flux index remained around 70 thanks to a total lack of sunspots. It is hard to believe we are heading for the summer solstice in the Northern hemisphere, especially with last week’s weather! Summer solstice is characterised by lower daytime maximum useable frequencies than winter, but higher night-time MUFs. Don’t write off 20 or 30 metres in the evening as the bands may well be open all night. Otherwise, the highlights are likely to be due to Sporadic-E, with June perhaps offering some of the best, with openings from 40 through to 10 metres.
Next week, NOAA predicts more of the same with the solar flux index pegged at 68-70 with the Kp index averaging around two. There is the risk of an increase in the Kp index this weekend thanks to an Earth-facing coronal hole, but this is unlikely to be long lasting.
VHF and up
We ended the week with the last of the very wet unsettled weather, but high pressure is making an appearance in the far south, which could well put Tropo back on the agenda again for the coming week. The regions most likely to benefit are southern England into the continent and across Biscay to Spain. These improved conditions may extend into northern Britain later.
The heavy thunderstorms last week brought almost daily GHz bands rain scatter conditions for those fortunate enough to be around to catch them. These showers should still be present in some northern areas at first next week, again providing a potential source for rain scatter.
As we said earlier, it’s high season for Sporadic -E and the jet stream distribution suggests that there will be some options for Sporadic-E because of the placement of these jet streams, although the strength looks weaker as we move through the coming week.
The Moon is at minimum declination this coming Tuesday and with apogee just a week away the Moon is only up for a few hours either side of midnight and path losses increase all week.
June has three daytime meteor showers. Two are over, but the Bootids shower, associated with comet 7P/Pons-Winnecke and peaking on June the 27th, produced high activity in 1998 and 2004. The last perihelion passage of the comet was in 2015, and no unusual activity is predicted for 2019.
And that’s all from the propagation team this week.
Category: GB2RS Propagation News
