HF News
What a difference a week can make! Last week we reported that the SFI was down in the 100s, but that it looked like there were spots coming around the Sun. This week they’ve arrived, pushing the solar flux index up to 142 on Thursday the 28th.
But with sunspots comes the risk of solar flares and coronal mass ejections, so don’t get too comfy! So far we have only seen minor C-class Flares so keep your fingers crossed.
Upper HF activity has been split between F2-layer propagation and Sporadic E. As always, there seems to be more activity on FT8 than CW or SSB, but it is also worth keeping an eye on the 10m beacons, which often spring out of the noise. You can find a list of 10m beacons at rsgb.org/main/technical/propagation/
Just follow the link to “Propagation Beacons”.
DX to be worked this week includes 5Z4/MM0ZBH (Kenya), 3G0Z and XR0Z (Juan Fernández Islands), ZL7IO (Chatham Islands), CP7DX (Bolivia) and VJ2L (Lord Howe Island). More details can be found at www.dx-world.net
Next week, NOAA predicts the solar flux index will remain in the 140s-150s range, with generally calm geomagnetic conditions and an estimated Kp index of two. There may be a brief excursion to four around June 4, but it is predicted to return to two the next day.
As we mentioned earlier, with up to 10 sunspot groups visible on the Sun’s surface anything could happen, so keep an eye on solarham.net for news of solar flares and CMEs. Otherwise, enjoy the good HF conditions while they last.
VHF and up
The lengthy spell of heat is releasing its grip and we are now seeing the start of a change over to unsettled weather driven by Atlantic weather systems crossing the country.
It can often take a while to properly reach the southeast, but there will be some rain here eventually. For most parts of the country, it will be a mix of occasional spells of rain or scattered heavy showers. Apart from transient ridges of high pressure in between the fronts, there is only a limited option for Tropo, in favour of rain scatter for the coming week.
The first week in June is often regarded as a prime period for Sporadic-E and the return of unsettled weather means that there should be some jet stream activity to generate atmospheric gravity waves that provide the wind shear in the E region and there is also a lesser-known meteor shower to provide the fuel for any Es, the Arietids, which is mainly a daytime shower.
The solar conditions have provided a few recent minor enhancements of the Kp index between Kp=1 and 4, but not enough to get excited about in a radio sense for aurora.
EME now, and this is a week to check out the kit. Moon declination reaches minimum this coming Monday. Combined with increasing path losses, as we also reach Lunar apogee on that day conditions will worsen until then due to the short Moon windows and low peak elevation. 144 MHz sky temperature is moderate to high all week, peaking at nearly 3,300 Kelvin on Tuesday.