Propagation News – 19 February 2017
Last week brought mostly settled conditions and the HF bands benefitted as a result. With a solar flux index in the mid 70s, and a K-index never higher than two before Thursday, it was an opportunity for the ionosphere to shine.
The maximum useable frequency was often just above 21MHz at times, bringing DX in from many parts of the world, including TL8TT in the Central African Republic. Other highlights included RI1ANR in Antarctica, 4JT4K Azerbaijan, and CE2AWW in Chile, all on 17 metres.
More settled conditions also brought better conditions at the bottom end of the spectrum with some very strong openings to the United States on 80m at dawn.
Next week NOAA predicts that the solar flux index should be around the 80 mark. Geomagnetic conditions are expected to be settled at first, perhaps declining from around Wednesday the 22nd to give a K-index of around four at times. Once again this is due to ongoing solar coronal hole activity.
We recommend getting your DXing in over the weekend and in the first half of the week, as conditions may be more unsettled as the enhanced solar wind impacts the Earth. At this time of year, HF favours diagonal paths across the equator, such as the UK to South America. This will start to shift towards more north-south paths, such as the UK to South Africa, as we head towards the spring equinox next month.
VHF and up
The predicted high pressure has become dominant over the south of Britain, and may help us with some limited tropo in the first half of this week before declining after midweek. The reason for the decline is that a large low will become resident to the north-east of Britain and bring some rain and windier weather as the high gets nudged away to the south. So, this is not the best week for tropo, although there are limited prospects in the first half of the week.
You could monitor the various rain radar websites to help predict short rain scatter openings on the gigahertz bands. Look at beacon signals on an SDR waterfall display for their characteristic broader signals, offset in frequency from the main carrier. Don’t expect too much from this rain as winter does not produce the sort of DX that we see in summer thunderstorms.
There are no major meteor showers this week, so keep looking for random meteor scatter contacts around dawn, when the earth is rotating into the flux of meteoric particles.
The Moon apogee on Sunday means peak path losses. Combined with low declination, reaching a minimum on Wednesday, it’s a week of short daytime windows at low elevation for EME.
Category: GB2RS Propagation News
