Propagation News – 9 February 2020
After sunspot group 2757 rotated out of view the Sun remained spotless with a solar flux index around 70. We had periods of geomagnetic disruption thanks to the effects of coronal holes, the worst seeing the Kp index hit four on Thursday morning. These storms resulted in visible aurora being reported at higher latitudes.
Monday saw the first of the RSGB’s 80m Club Championship events with an SSB contest. Participants complained about the poor propagation, with continental stations being stronger than locals. This was reflected in the ionosonde data at propquest.co.uk, that showed the f0F2 critical frequency, as measured at RAF Fairford, as 2.875MHz at the start of the contest and only 3.175MHz at the end. Meanwhile, Chilton recorded 3.7MHz at the start of the contest and 3.5MHz at the end.
So, you can see that short-range propagation on 80m was marginal and favoured different parts of the country. Next week, there is the possibility that strong jet streams may provide some low-band sporadic E enhancement for evening nets when the foF2 has deserted us.
Thursday saw an HF enhancement, possibly linked to the raised Kp index, with maximum usable frequencies creeping above 21MHz and 15m FT8 openings into the Canary Islands, the Azores, Greece and European Russia. There were also 15m FT8 openings to South America later in the afternoon.
CDXC members have also reported contacts last week with TI9A, Cocos Island, off Costa Rica, and HU1DL in El Salvador. Excitement is also building for the VP8PJ South Orkney DXpedition that should start later this month.
Next week, NOAA predicts the solar flux index will remain around 70 with more settled geomagnetic conditions after the effects of the current high-speed solar wind diminish.
VHF and up
After a brief period of tropo in the second half of last week, we are now about to enter a period of very unsettled weather with deep lows passing by the far north of Britain. This means that tropo will not be a feature this coming week and time may be better spent making sure the antenna ropes are secure and towers lowered if the forecast looks severe.
At present, the strongest winds are likely in northern and western areas, but with such a strong Atlantic jet stream there is a huge amount of energy available to spin up very deep lows in less than 24 hours. The message therefore is to keep up to date with the latest forecasts, because the track of such lows can change markedly over a few hours.
There is one propagation silver lining to this type of weather, which is possible microwave rain scatter as squally fronts or showers pass by.
One of the models does build a high over the continent at the end of next week with a possibility of some tropo into France, but only from the south-eastern corner of the country.
Moon declination goes negative on Wednesday, but with perigee on Monday, it’s still a good week for EME. Path losses are at their lowest and 144 MHz sky noise is low all week.
There are no major meteor showers this week, and we are now well into the winter minimum for random meteors. The best time for random meteor scatter QSOs is always around dawn when the Earth is rotating towards the main meteor flux.
Category: GB2RS Propagation News
