Propagation News – 8 January 2017

Firstly, a happy New Year to all. We’ve got off to a bad start with a massive coronal hole on the sun that has rewarded us with dire predictions for the period up to 8 January. We can expect the K-index to hit four or five at times with a consequent lowering of maximum useable frequencies and noisy HF conditions. This is not being helped by a complete lack of sunspots, depressing the solar flux index into the low 70s.

As a result daytime critical frequencies over the UK are struggling to exceed five to six megahertz at times. This means that 60 and 80 metres are often the best bands for inter-G working, with 40 metres mainly being reserved for long-skip contacts into Europe.

On longer distance contacts, although 20 metres is the best all-round band, we are often seeing longer-range 17m openings around lunchtime and early afternoon. However, we are still in the winter sporadic E season. Although these openings can be short-lived and unreliable, it is worth checking the 10 metre beacons every now and again.

Over the next week the K-index is predicted to dip to around two or three, with the solar flux index remaining in the mid-seventies.

VHF and up

At the start of next week we have high pressure over the near continent, so perhaps some weak tropospheric openings into Europe may appear for southern stations. It will need some moisture at the surface underneath the inversion to make conditions work, so look for mist and fog or a blanket of cloud to show the presence of moisture near the inversion. Remember, it’s the contrast of moisture across the inversion that allows the duct to work.

Deepening lows will then cross to the north of Scotland and drive colder, drier air south again, along with very strong winds at times. This will effectively finish any tropo after midweek.

In view of the active lows later in the week, there will also be some strong jet stream activity at times, which is always worth noting as a potential marker for some of the rarer mid-winter sporadic E.

The short, but intense, Quadrantids meteor shower is past its peak, so continue to look for the dawn peak in random activity. We are now heading into the winter minimum for meteor activity. Moon declination is high all week and losses are low, with perigee on Tuesday. So it is a good week for EME.

Category: GB2RS Propagation News