Propagation News – 4 November 2018

Quieter geomagnetic conditions and a better autumn ionosphere meant HF conditions were quite good this week. GB2RS listeners reported plenty of DX activity during CQ Worldwide last weekend, including openings on 21 and 28MHz at times. While HF propagation was never going to be as good as it is at sunspot maximum, it does show that the higher bands can and do open with no sunspots, albeit sometimes briefly.

For the next week the sun is predicted to remain pretty spotless, with a solar flux index of around 68-70. Once again it will be the absence or presence of the effects of solar coronal holes that will drive HF propagation.

As you read or hear this report, the Earth is due to be subject to a geomagnetic storm, thanks to fast-moving solar particles from a large coronal hole that became Earth-facing on Thursday. This is predicted to send the Kp index to five on or by Saturday the 3rd. After an initial potential positive phase, where HF conditions may get better for a short time, the negative main phase will likely see maximum useable frequencies decline and auroral-type conditions predominate. The good news is that geomagnetic conditions should improve by Wednesday or Thursday. Beyond that, it is more difficult to predict.

Do make the most of the better autumn HF conditions when you can. Steve, G0KYA reports that his 20m 5W WSPR signal was received from as far away as Japan, Australia, Reunion Island, Antarctica, Alaska, San Francisco and Brazil this week.

And now the VHF and up propagation news.

With low pressure to the west of Britain, it will be a relatively mild southerly flow of air across the British Isles during the next week. Tropo does not appear to be a major feature, since we are nearer to low pressure than high pressure. The better chances are more likely over the eastern side of the country and down into France or across the southern North Sea. The southerly weather pattern may have some areas of heavy rain moving north at times, so there is a possibility of some rain scatter on the microwave bands.

There are a few standard weather rules for getting the most out of your shack time; such as conditions are usually more favourable for Tropo overnight or during the morning, especially on occasions when fog is slow to clear. Heavy rain showers are most likely around the coast, so look for the brighter echoes on rain radar displays for rain scatter possibilities. Lastly, there is always a chance of aurora and meteor scatter to liven the VHF bands, so watch the band reports and clusters to stay ahead of the game.

The Moon’s declination goes negative again on Monday and its distance from the Earth is increasing, so EME path losses will rise and Moon windows will shorten as the week progresses.

And that’s all from the propagation team this week.

Category: GB2RS Propagation News