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Propagation News – 9 June 2019

We had a very quiet, settled Sun last week.

The solar flux index never got above 70, reflecting a complete lack of sunspots, while the Kp index eventually decreased to one or two, due to a lack of coronal holes on the solar surface.

The net result was that HF conditions were not bad, but definitely not outstanding. Last weekend’s NFD saw many teams with better scores than last year, although the bulk of the propagation was to Europe.

40 metres has become the new 20m, being open during the day as well as in the evening, while openings on the bands above 20m have been fleeting and largely restricted to short-skip Sporadic-E.

A station on the west coast of the USA was worked by G4ARN/P, but that was largely due to the other station’s antenna system.

Another DX nugget this week has been 3D2CR on Conway Reef in the South Pacific. This has been worked by a few UK amateurs equipped with high-mounted beams. As the long and short path routes both go over the poles, this is an indication that geomagnetic conditions have been good.

Sporadic-E has not been so prevalent this week, but there have been short openings. A surprise was hearing GB19CH, the Scotland World Cup HQ Station, on 28MHz CW on Thursday, here in Norfolk. This was undoubtedly short-skip Sporadic-E. Special Event Stations AM70C, AM70L and AM70P in Spain were also frequent visitors to 28MHz.

Next week, NOAA predicts the solar flux index will continue around 70-72, while geomagnetic conditions will be settled, with a maximum Kp index of two. Maximum useable frequencies over a 3,000km-long path will peak at about 16-17.5MHz, so 20 metres continues to be the daytime DX band of choice.

With an unsettled weather week coming up, this time of the year often means some potentially heavy rain with a chance of thunder. Therefore the first propagation mode to get a mention this week is rain scatter on the microwave bands. Use one of the many radar displays available on the web to track the storms.

Now it’s high summer, the Sporadic-E season is well under way. Recent days have been a bit lacklustre in a European sense, although some choice DX has been worked on six metres into Central Africa.

Given that jet streams at 10km altitude in the weather part of the atmosphere are known to play a role in the location of Sporadic-E at 100km, it’s reassuring to see that there will be some significant jet streams over our part of Europe during the coming week.

At various times they will support possible Sporadic-E paths from Scandinavia round to Spain. The main operating tip is to check the bands late morning and again late afternoon and early evening, starting with 10m and working up through six, four and two metres.

Unfortunately all of this depends upon the other parameters that influence Sporadic-E coming into line, but at least the weather part looks promising. With predominantly low pressure, there is a limited chance of Tropo featuring much during the coming week.

The Moon is past peak declination perigee, but it is still a good week for EME, albeit with shortening Moon windows and path losses increasing.

After last week’s peak of the daytime Arietids meteor shower, there are no significant showers in the upcoming week. And that’s all from the propagation team this week.

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