sabato 11 giugno 2016

Propagation News – 12 June 2016

This week saw mixed HF propagation conditions. We were right to predict a geomagnetic disturbance for last weekend, although the plasma hit the Earth right at the end of National Field Day. This led to widespread aurora as the K-index hit five and then six.

Propagation during field day was lacklustre due to a lack of sunspots and the seasonal doldrums. But there has been some decent propagation and excellent DX this week. Andy, M0NKR reports working 9Y4D in Trinidad on 6m, possibly via multi-hop sporadic E, and XR0YS Easter Island on 10m, which, after careful examination, was most likely F layer propagation.

This week the solar flux index is predicted to be in the range 85-95, although on Thursday there was only one sunspot group visible.

Geomagnetic disturbances due to coronal hole activity are predicted to remain an issue this weekend, with the K-index possibly increasing to four. Next week may also remain unsettled, with the K-index predicted to hit five on Friday the 17th.

We are now entering the period for six metre summer solstice short path propagation when signals from Asia may be heard in Europe from over the North Pole. Stations equipped with six metres are encouraged to get on the band as this, plus multi-hop sporadic E, can bring some surprises.

VHF and up propagation news:

Propagation folklore has the first week in June high on the list of sporadic E activity. Last week, we had some fine sporadic E, some excellent tropo to the north and GHz-band rain scatter to the near continent. The northerly tropo coupled signals into the aurora giving some remarkable mixed mode DX for the lucky few.

Next week, we may struggle to achieve any tropo of note, as low pressure is due to move into the British Isles. This will bring showery weather ending the tropo spell over the North Sea.

A new high to the south-west late in the week may allow paths to the south across Biscay and down past Portugal to the west coast of North Africa.

There should be plenty of opportunities for sporadic E during next week when weather elements are favourable. The principal elements are jet streams, and it is likely that these will be located over the near continent as the weather turns unsettled.

This could bring propagation towards the Balkans and round through Italy to Iberia. Remember that there are usually two main periods of activity, late morning and early evening, but very active events can last for much of the day.