Propagation News – 11 September 2022

What a week we have just had! The Kp index stayed at four or more for most of the week thanks to an enhanced solar wind stream. This continued to stir up geomagnetic activity with minor ,G1, storm conditions.

Visible aurora have been reported at higher latitudes.

Sunspot region 3089 has now rotated behind the Sun’s west limb, which may help with conditions as it was responsible for an M-class solar flare on the fifth.

A major space weather event took place during the week, but luckily it was on the far side of the Sun. A large, full halo coronal mass ejection, CME, became visible on imagery courtesy of both the LASCO and STEREO Ahead spacecraft. This was possibly connected with active region 3088, which will rotate back into view next week so perhaps look out for more disturbed conditions.

News of sunspots has become almost secondary to the geomagnetic reports, but at the time of writing, there were five active regions facing the Earth and a solar flux index of 126. This has remained roughly static all week.

Despite the disturbed conditions, ionospheric propagation has remained good at times, with MUFs over 3,000km exceeding 21MHz according to Propquest.co.uk. This may be mainly due to a seasonal change in the ionosphere, which may see MUFs rising as we go further into Autumn. Meanwhile fourteen megahertz may remain more reliable for DX, while the higher bands may provide more fleeting openings.

A quick tip – the feed from the Chilton Digisonde on Propquest has not been terribly reliable recently so we recommend switching to Fairford data and refreshing the display for the best results if need be.

Next week NOAA predicts that the solar flux may remain in the mid-120s. Geomagnetic conditions are due to be unsettled again and we may see the Kp index rise to four, especially around the 13th-15th. Otherwise, expect it to be around two to three.

VHF and up

The large slow low pressure that brought numerous heavy showers and thunderstorms to dent the drought has started to drift away to the east and will allow one more low and area of rain to affect the country at the end of this weekend and early this coming week.

There is still an opportunity for some good rain scatter on the GHz bands, but eventually, it seems that high pressure may try to return around the middle of the week. Not a very strong signal and the models suggest that low pressure is back again by the end of the week, meaning not an especially good, and probably short-lasting, Tropo event.

So, rain scatter on the GHz bands is the primary mode, followed by a hint of Tropo midweek and then don’t forget about meteor scatter and aurora as occasional “long-shots”.

The Epsilon-Perseids meteor shower is still active and the Sextantids shower gets under way this week.

The geomagnetic field has been very disturbed lately and there have been some good aurora openings recently, so you’ve probably already been keeping an eye on the Kp index; anything above five should be worth checking out.

With the Moon at positive declination from today, and past last Wednesday’s perigee, expect low but increasing path losses and lengthening Moon windows. 144MHz sky noise is low all week, not exceeding 500 Kelvin until next Saturday night.

Category: GB2RS Propagation News