Propagation News – 4 August 2019

| August 2, 2019

A solar coronal hole pushed the Kp index to three last week and the solar flux index was static at 66. The plasma from the hole impacted the Earth on Wednesday, but it didn’t have the dire results that many had predicted. In fact, there was a pre-auroral enhancement that saw the maximum usable frequency over a 3,000km path climb to more than 18MHz at 2030UTC on Tuesday, the 30th. Two even larger coronal holes followed, matter from which is expected to hit the Earth on Sunday, the 4th. These latter holes have a positive polarity though, so the solar wind may not connect fully with the Earth’s magnetic field.

Next week NOAA has the solar flux index pegged at 67, but the good news is that once the high-speed solar wind stream from this latest coronal hole calms down we can expect more settled geomagnetic conditions.

In other news, 40m has been humming at night with many reports of US and Caribbean stations being worked.

The CY9C DXpedition to St Paul Island, off Nova Scotia, should now be under way. It’s planned to last until 8 August. The VOACAP online HF prediction tool shows that 20m from 2100 to 2200UTC may be favourite for a contact. Thirty metres offers an even better opportunity from 2000UTC to midnight, but is obviously restricted to CW and data modes. Later, 40 and 80 metres take over through the early hours, until sunrise. Good news for lesser-equipped stations is that CY9C is using FT8 in Fox and Hound mode at times.

VHF and up

The end of this last week, and most of next, will still be on the unsettled side of high summer with areas of low pressure close to the British Isles. At this time of the year it often means heavy showery bursts of rain with a risk of thunder in places, so that’s a good signal for rain scatter on the microwave bands. High pressure is just putting in an appearance over the North Sea and Biscay, which means that some tropo paths might develop to the continent.

We have a feeling that the sporadic E season is in its last phase now, but don’t abandon the idea that sporadic E can still occur, since some good openings have been seen in previous years even into the first week of September. Keep a check on the clusters for the much rarer openings in August. They can be productive, although tend to be short-lived.

Moon declination goes negative on Monday so peak Moon elevations will be under 20 degrees by the end of the week. EME Moon windows will therefore be short. Path losses will still be reasonable though as we are still two weeks from apogee.

While the Perseids meteor shower doesn’t reach its peak for another week, the shower is quite broad so you can expect improving meteor scatter conditions as the week progresses.

Category: GB2RS Propagation News