Propagation News – 20 August 2017
Last week saw the solar flux index in the low to mid-70s. Geomagnetic conditions were generally quiet earlier in the week, with some choice DX to be had. Andy, M0NKR reported working the Marshall Islands in the Pacific on 20m CW at 0700UTC on Wednesday, while Del, W8KJP in Florida, USA, was heard by G0KYA on 40m CW at 2221UTC using a simple wire antenna. But the good conditions didn’t last and the ionosphere became disturbed on Thursday 17th due to the effects of a high-speed solar wind stream from a large high-latitude coronal hole on the Sun. This had a very strong south-facing magnetic field component that meant it more easily coupled with the Earth’s magnetic field. The K-index surged to five and remained like that for at least nine hours, driving maximum usable frequencies down to around 14MHz and causing very noisy bands. Next week, NOAA predicts the solar flux index will be in the high 60s and, after an unsettled start, geomagnetic conditions may settle for the rest of the week.
Monday the 21st brings a total solar eclipse, which will be visible across the USA. A QSO party is planned so many US stations may be active. The partial eclipse starts at 1546UTC and ends at 2104 UTC. Totality will move east across the US, starting at 1648UTC and ending in the Atlantic at 2001UTC. A feature on the eclipse appeared in the August edition of RadCom, but there is a lot more information on the web. It is not known whether any propagation effects will be observable from the UK, but it is a rare opportunity to check.
VHF and up
The unsettled weather crossing the country this weekend will contain some remnants of Hurricane Gert. This means some very warm and moist tropical air could produce some heavy rain. Gigahertz band rain scatter may be an option, but as the next high pressure builds in from the west towards mid-week, tropo should become available. This should be to the south and south-west across southern UK and Biscay. The rest of the week will probably see high pressure remaining just to the west of the UK, so any tropo will be biased to that side of the country, with showery activity over the east, closest to the low pressure over Denmark.
Sporadic E is still looking viable, with a strong jet stream over the UK and near continent, although this may weaken after mid-week, meaning better sporadic E prospects before then. The end of the main sporadic E season is not far off now, so every event is worth chasing. Check beacons on 10m or look for short skip on 20m, then probe that direction on 6m for any sporadic E. If you don’t call, the DX may not know the band is open.
Even though the Perseids shower is well behind us, random meteor rates are still at their highest of the year so don’t give up on meteor scatter just yet. Moon declination goes negative on Thursday and losses are increasing so get your EME QSOs in early this week before the Moon gets too low in the sky.
Category: GB2RS Propagation News
