Propagation News – 12 July 2020
An elevated solar wind stream moved past Earth late on 4 July and early on the 5th, sending the Kp index to three. This was the most significant solar event of the last week as otherwise the Sun remained calm. The Kp index remained at one or zero for the rest of the week, which no doubt helped boost propagation. There were no sunspots this week after the minor group, region 2766—which pushed the sunspot number to 12—vanished on Monday. Note that the number 12 represents two sunspots (2) in one group (+10), so it wasn’t quite as exciting as it sounds. Otherwise there was little to write home about. Sporadic E continues to be the major mode of propagation, although there were days when it was more sporadic than the previous week! We have probably seen the best of the sporadic E season now although it should keep running until late August, albeit at lower levels. If previous experience is anything to go by, we can expect a few bigger openings yet so please don’t write off 10 metres completely.
The NOAA space weather prediction for next week doesn’t exactly inspire either. It has the solar flux index pegged at 68-69, with a maximum planetary Kp index of two. The STEREO Ahead spacecraft view shows very little in the way of forthcoming activity, other than a few bright spots in the extreme ultraviolet view that may or may not come to something as the Sun rotates.
Looking for some good news, according to the Chilton ionosonde data, 20 metres is generally staying open on 3,000km paths until around midnight on most nights, although you may find 30 metres more reliable.
VHF and up
It’s looking like another week of changes with last week’s unsettled weather making way for a new ridge of high pressure over this weekend. This means that, after a period of potential GHz bands rain scatter, we are now heading into some tropo prospects, especially in the south, for paths into France and across Biscay to Spain. But low pressure is never far away to the north, particularly after mid-week when a low passes close to Scotland and showery fronts are driven across the country to give a few rain scatter options again.
The sporadic E season is still out there and as usual the best advice is to check the bands and clusters for activity mid-morning and again late afternoon and early evening.
This Sunday, Moon declination goes positive and 144MHz sky noise is low but rising as the week progresses. Apogee is Sunday night so path losses will be falling throughout the week. Peak Moon declination is just a week away, meaning longer Moon windows—time to get that EME system up and running again.
There are no major meteor showers this week, so continue to operate around local dawn for the best chance of random meteor scatter contacts.
Category: GB2RS Propagation News
