HF News

Last week was not bad for HF propagation, but probably not as good as the previous one. 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.

HF highlights this week included the 7Q7RU Russian Robinson Club DXpedition to Malawi, which has been worked from the UK on many bands including 12 metres. The DXpedition has shown how effective the FT8 fox and hounds mode can be and has given many amateurs a new entity in their log.

There have also been reports of 10m SSB contacts with Australia, especially by better-equipped stations. Let’s hope that contacts with VK become more commonplace as the solar cycle progresses.

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. To recap, a coronal hole is an area of the Sun with an open, magnetic field that allows the solar wind to escape more readily into space, resulting in streams of relatively fast solar wind.

Coronal holes appear as dark areas when the Sun is photographed in extreme ultraviolet light, such as with the Solar Dynamics Observatory imagery, because they are cooler, less dense regions than the surrounding plasma.

For the latest SDO images see solarham.com.

NOAA predicts the Kp index could rise to four on Sunday 22nd 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, over the Continent, 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 Es events on 10m and 6m in the past week, so it's never safe to assume there is only a summer season for Es. Admittedly it's not usually a great response in November, but it can and does happen! This event occurred around the peak of the Leonids meteor shower, which possibly delivered a new influx of raw material as long-lived metallic ions when they burned up upon entering the upper atmosphere.

Just one minor meteor shower this 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. 144 MHz sky noise is low all week, but rising above 300 Kelvin from Thursday.