Propagation News – 22 December 2024

The last week was a little more disturbed than usual and we had a Kp index that hit 5.33. An enhanced solar wind stream contributed to active geomagnetic conditions and an interplanetary shockwave, that swept past Earth at 0519UTC on the 17 December, caused minor G1 geomagnetic storming.

A far-sided halo coronal mass ejection event also occurred later on the 17 December at 1600UTC although this was not directed towards Earth.

This shows that the Sun is still very active, and we should not be surprised if we experience more solar flares and CMEs.

The solar flux index stayed in the 160s and 170s and we should keep an eye on active region 3927, which is currently turning to be Earth-facing and has already been the source of some C-class solar flares.

Next week NOAA predicts that the solar flux index may rise slightly to be in the 180s. The largest Kp index forecast is 2, which probably means that NOAA is unsure about what will actually happen.

We are pleased to report that OF9X is once again on the air from the land of Santa Claus in Lapland. Up to 16 operators will operate Santa Radio on the 160 to 6m bands using CW, SSB, RTTY, FT4 and FT8. They have already been spotted on the 30 and 20m bands using CW and on the 12 and 17m bands using RTTY. So, there is plenty of scope to work them.

According to prediction program Proppy, paths to Lapland should be open on 14MHz from 0800UTC to 1800UTC. On 28MHz, expect them to be open from 0930 to 1500UTC. The 80 and 40m bands should be mainly open during the hours of darkness.

As always, across the Christmas period, we recommend that you use solarham.com and propquest.co.uk for real-time updates on the solar and ionospheric conditions.

 VHF and up

Last week ended in a colder unsettled period of weather with strong north-westerly winds and spells of rain or showers.

The air is sufficiently cold that some snow is possible over northern hills. This is potentially good news for rain or snow scatter, especially off fast-moving showers down the coastal fringes of the UK.

Although the nearest high remains near to the Azores to begin with, it slowly migrates east to France and, by Christmas, to central Europe. This will bring high pressure and possible Tropo onto Santa’s list from Christmas Eve onwards. Look for patches of misty low cloud or fog for the best conditions.

As usual, check for other modes. Meteor scatter and aurora are both worth consideration and this is a prime time for out-of-season Sporadic-E between now and about mid-January.

One of the helpful aspects of looking for winter Sporadic-E is that quite often the jet streams are significantly stronger than in the more traditional summer Sporadic-E season. Jet streams are a good source of turbulence that can eventually propagate up to the E region to make Sporadic-E propagation.

Jet streams are shown on upper air charts and can be a good geographical guide to Sporadic-E prospects in the summer and should therefore be similarly consulted for these winter events.

In this case, they tell us that the first half of the coming week, up to Christmas Day, is well set up with a northerly jet stream over central Europe and, more importantly, crossing the Alps. So, a second mode goes on to Santa’s list.

Check the VHF Cluster’s Sporadic-E graphs at propquest.co.uk for early signs of activity, particularly for paths to the southeast into Italy and the Balkans.

The Moon started this weekend with positive declination but goes negative late today, the 22 December. Path losses are at their highest due to apogee on Christmas Eve. 144MHz sky noise is high until Wednesday, including near-eclipse conditions all day on Monday.

That’s it for this year. How about making a New Year’s resolution to try a new mode? Maybe use SSB or CW on VHF now and again and put out lots of CQ calls in 2025!

Category: GB2RS Propagation News