Propagation News – 22 November 2020

Last week was not bad for HF propagation, but probably not as good as the previous period. The solar flux index remained in the mid-to-high 70s, but the upside was that we had quiet geomagnetic conditions, which helped settle the ionosphere. The result was that maximum usable frequencies over 3,000km remained quite high, with 12 metres often being open. There was even the occasional long-distance opening on 10 metres, including SSB contacts with Australia, especially by better-equipped stations.

Next week may be better as sunspot group 2783 rotates into an Earth-facing position. NOAA predicts the SFI will remain in the range 70-75, but this could easily be exceeded if sunspot 2783 becomes more active. Unfortunately, geomagnetic conditions may not be as favourable next week due to a large coronal hole on the Sun’s surface.

NOAA predicts the Kp index could rise to four on Sunday, 22 November and again on the 24th and 25th. Things could then settle down with a maximum Kp index of two, just in time for the CQ Worldwide CW contest on the weekend of the 28th and 29th. So it looks like the latter half of the week will be better for HF propagation than the first half.

VHF and up

This is often regarded as an unsettled time of year, but can occasionally bring quite settled weather, typical of high-pressure systems. Unfortunately, there is once again no real sign of any substantial high pressure, other than the occasional brief ridge between successive lows and their fronts.  Like last week, any high pressure is likely to be closer to southern Britain and over the Continent, therefore favouring southern England to France and Biscay for the more optimistic operators. It’s another week to look for GHz Bands rain scatter, with much variability expected in timing. It’s best to follow events via the daily forecasts to find the most likely opportunities.

There have been a few out-of-season sporadic E events on 10m and 6m in the past week, so it’s never safe to assume there is only a summer season for sporadic E. Admittedly it’s not usually a great response in November, but it can and does happen!

Just one minor meteor shower this coming week. The November Orionids peaks on the 28th, with a zenithal hourly rate of just three. Moon declination goes positive again on Wednesday, so visibility windows will lengthen all week. With the Moon approaching apogee on Friday, path losses are at their highest. 144MHz sky noise is low all week, but rising above 300 Kelvin from Thursday.

Category: GB2RS Propagation News