Propagation News – 12 January 2020

| January 10, 2020

Having predicted in last week’s broadcast that there would be no geomagnetic disturbances, we did in fact have two periods with an elevated Kp index this week. The first occurred on 5 January, when the Kp index hit four. This was due to the impact of the solar wind. The Kp index rose again to four on Thursday, the 9th, again due to the effects of a high-speed solar wind stream from a large geo-effective coronal hole.

On Thursday a new spot was seen forming in the Sun’s north-east quadrant. This event, coupled with other recent reports of new solar cycle 25 sunspots, suggest that the cycle is starting to get under way. The next few months should give us a better idea of how it is progressing. Andy, M0NKR reports that he has now worked more than 100 countries since 1 January, so there is DX to be had on HF!

Meanwhile, 10 metres was alive this week due to winter sporadic E. An opening at lunchtime on the 8th saw short-skip path openings on FT8 to Germany, Slovenia, Croatia, Latvia, the Czech Republic, Sweden, Finland and others. More on this in the VHF report. Interestingly, there were no CW or SSB signals on the band at this time. This just goes to show that you shouldn’t write 10m off at this time of year.

Next week NOAA predicts the solar flux index will remain around 70, with mainly quiet geomagnetic conditions. We may have a geomagnetic disturbance on the 14th and 15th which could see the Kp index rise to four again. As always, look out for a pre-auroral enhancement at the beginning of the disturbance, but as it progresses expect to see lowered maximum usable frequencies and noisy bands.

VHF and up

As we recover from the excesses of Christmas tropo and start a New Year, the weather continues to provide some interest. Firstly, the northern half of the country will be dominated by deep Atlantic lows, which will mean strong winds at times with rain or snow in the north, and a good chance of further episodes of scatter paths on the microwave bands. The south will, for the most part, be on the edge of the main low track and there may just be a chance to link into the high pressure via tropo, but this doesn’t look like a good option.

Believe it or not, there is still one more roll of the dice for upper HF and VHF propagation and that may indirectly be the result of all this disturbed weather. The jet stream has been very strong, which is typical of winter months and, lying across the UK and northern Europe into Scandinavia, has produced some out-of-season sporadic E on 10m and 6m. Always worth a check, but the position of the jet stream and its strength may not be as favourable later in the week.

Moon declination is still positive but declining, going negative again on Thursday. Path losses are at their lowest at perigee on Monday. This and the low 144MHz sky noise means a good week for EME.

We are now entering the winter minimum of meteor activity, with just two more showers before the Lyrids at the end of April. Best opportunities for random QSOs will continue to be in the early morning around dawn.

Category: GB2RS Propagation News