Propagation News – 15 February 2015

| February 13, 2015

This week the solar flux index declined slightly to be in the 130s, pretty much as predicted by NOAA. The observed sunspot number for the week also declined, being 76 on Thursday 12 February. Geomagnetic conditions were largely settled, with the A index keeping below 15 all week.

For next week, NOAA predicts more of the same with the solar flux index being in the range 145-155. Geomagnetic conditions may also be reasonably settled, with the A index predicted to remain below 15 again.

This week expect to see maximum usable frequencies pass 28MHz on paths to the US eastern seaboard and Midwest states, with a reliability of about 20 to 30 percent. On paths to the West Coast, including California, you may be better dropping to 21MHz or even 18MHz.

Finally, this week NASA launched the Deep Space Climate Observatory satellite. This will succeed NASA’s ACE satellite and provide solar wind alerts and warnings from its L1 orbital position—the neutral gravity point between the Earth and Sun, approximately one million miles from us. The satellite will typically be able to provide the Earth with a 15 to 60 minute warning time of a surge of particles known as a coronal mass ejection, or CME, which are associated with geomagnetic storms.

VHF and up propagation news

The next week will not provide quite the success of last, when stations used the tropo conditions brought by the large area of high pressure to work across northern Europe and into Sweden. That particular high has long gone now and our next opportunity comes from another high moving in from the Atlantic after midweek.

This does not look quite as widespread and will probably be more for southern areas of the UK, since there will be windier weather and weak fronts crossing Scotland later in the week.

Nonetheless, it’s still worth checking the VHF/UHF bands in the second half of the week for lift conditions, especially into Europe since, although one model retains the high pressure into the weekend, there are other solutions which bring strong lows across the country and any lift will be short-lived.

The moon is at its lowest declination today so EME operators will get short but increasing moon windows next week coupled with lowest losses on Thursday.

Still little chance of Sporadic-E openings this week and no meteor showers, so look for early morning random meteor scatter contacts on the lower VHF bands.

Category: GB2RS Propagation News