Propagation News – 25 September 2022

| September 23, 2022

Last week saw the solar flux index decline very slightly to 137. The good news is that we have had reasonably-settled geomagnetic conditions. The highest Kp index has been three, but it has often been at zero or one. This is good news as it means that the ionosphere has had a chance to develop.

The MUF over a 3,000km path has often exceeded 28MHz, especially in the early afternoons. This will probably improve further as we head into late September and early October.

The result is that some good DX has been available. J20EE in Djibouti, Africa has been workable on 10m CW, as has ZD7BG on St Helena. And ZL7/K5WE on Chatham Island is reported to have been “very easy” to work on 40m. The 4X6TU IBP beacon in Givatayim, Israel, on 28.200MHz has been audible down to one watt recently, which is very encouraging. Numerous North American low-power beacons have also been audible, including the five-watt K5TLL on 28.298MHz in Hattiesburg, Mississippi.

As we head into next week, the Sun will be dominated by active regions 3105 and 3107. Region 3015 is actually the remains of AR 3089. A cluster of sunspots in 3105 continue to turn into view off the south-east limb and for now, they remain mostly stable, however minor solar flares will be quite possible.

NOAA predicts that the solar flux index may decline to the mid-120s next week. Geomagnetic conditions are predicted to remain calm, at least until the 29th when the Kp index is predicted to rise to five or even six. A single CME could soon disrupt the calm, so don’t expect the good conditions to last.

VHF and up

The weather has a noticeable autumn flavour to it lately and the coming week is continuing that theme.

As this was being prepared on Wednesday evening, there is a hint of tropo over the southern half of the British Isles, but as soon as a cold front completes its journey south on Thursday, we enter a period of cooler north-westerly winds. This will bring rain and showers, and means that for most of this weekend and next week rain scatter is a good option for the GHz bands.

Late in the week, and probably nearer next weekend, we find another high edging closer to Ireland and western Britain, perhaps bringing some patchy tropo down the western side of the country.

A further possibility is for meteor scatter and auroral propagation to present themselves as an option, but see the HF section earlier for the solar details and implications. The Kp index rising above five will be a useful guide for the chance of aurora.

There are no major showers in the coming week, although towards the end there may be some early Orionids shower reflections. This shower will peak between 2 and 7 October.

It is also worth watching for reflections during the daytime from the Sextantid meteor shower, which is active until 9 October. The peak is expected to be around 27 September. Good hunting!

The Moon will be low in the sky throughout this week and as this coincides with the Moon getting closest to the Earth, path losses will be lowest.

With the equinox now past, the Sun will not appear above the Ecliptic again for another six months. This will make Sun-to-cold-sky noise measurements less easy. If you need to make these measurements, and there are few EME operators who don’t, now is probably a good time to do them before those horizon trees get in the way!

Category: GB2RS Propagation News