Propagation News – 20 February 2022
Last week was pretty subdued in terms of sunspots, but it looks like we missed one of the most impressive space weather events of Solar Cycle 25. A bright, fast-moving coronal mass ejection, or CME, was visible coming off the far side of the Sun on imagery from the STEREO Ahead spacecraft. Had this event been Earth facing, we could only presume that a large-scale geomagnetic storm may have been triggered. Just how big is hard to judge. Other than that, the Kp index has been in the range of one to three, so nothing too dramatic.
Sunspot-wise, there have been eight active groups but they have all been small and the solar flux index has steadfastly remained in the low 100s.
Unfortunately, it looks like we will have more of the same as NOAA predicts that next week the SFI will be in the range 102-108. Geomagnetic conditions are predicted to be settled, at least until around Tuesday the 22nd to Thursday the 24th, when the Kp index could rise to five. There is also a large coronal hole that will be Earth-facing by Friday the 18th. As such, this could also trigger an elevated Kp index, perhaps later this weekend.
To check, keep an eye on the Real Time Solar Wind indicator on solarham.com. If the solar wind speed rises and the Bz swings southwards (negative) we may expect the solar plasma to more easily couple with the Earth’s magnetic field and the Kp index to rise shortly after.
Radio-wise, please note it is the ARRL DX CW contest this weekend. This is a great opportunity to work much-needed areas for your Worked All States award. And this may be the last good chance to work the US before the summer HF doldrums start in a couple of month’s time.
VHF and up
I hope that everyone’s antennas survived the gales over the last few days, as the very strong jet stream across the Atlantic is providing plenty of severe weather for the fringes of Europe with damaging gales and plenty of tense moments for big antenna arrays.
The coming week shows little change, with a continuation of the unsettled weather and further windy periods as deepening lows cross the country. These will bring some cold air too, and snowfall in some areas may put added stress on the antenna wires and beams. All this means little chance of seeing any Tropo and, like last week, only a chance of aurora, or meteor scatter in the early mornings, to provide variety.
This is a good time to get the locator square count up on the various satellites. QO-100 is always a banker for making QSOs and worth the effort of setting up a small system.
Moon declination is negative again, with shortening Moon windows and lower peak elevation as the week progresses. With lowest losses as we approach perigee next Saturday, the upside is that if you have a clear low angle of take-off to the horizon, it’s the best period for GHz band EME.
For VHFers, if you also have low site noise you can get a shot at digimode EME without the need for elevation control. QSOs can often be made with the big guns using legal QRO and a single Yagi. 144MHz sky noise is low to moderate until Friday, reaching 2,400 Kelvin at Moonset.
Category: GB2RS Propagation News
