venerdì 3 febbraio 2017

Propagation News – 5 February 2017

Last week’s prediction about geomagnetically-disturbed conditions turned out to be correct, with the K-index soaring to five during the week. This resulted in visible aurora at high latitudes, as local midnight is often the time when aurorae and disturbed conditions hit their peak. There were three small sunspot groups visible on the solar surface on Thursday, but these only pushed the solar flux index to 76.

Next week, NOAA predicts similar solar parameters, with the solar flux index in the seventies. Sunday the fifth may be geomagnetically unsettled, but we should then get a better period of quiet conditions. This may allow the ionosphere to recover, with the possibility of better DX openings from the 6th. Expect daytime maximum usable frequencies over 3,000 kilometres to peak at around 15 metres at times, with 17 and 20 being more reliable.

Daytime critical frequencies may peak around 7MHz, although the 5MHz band will be more reliable for intra-UK contacts. Night-time critical frequencies may exceed 3.5MHz at times, offering the potential for DX on 80 and even 40 metres. A settled polar ionosphere can sometimes be a good indicator for the lower bands.

Bob, MD0CCE reported good Top Band openings to the USA on many occasions last month. The evening of 24 January also provided one of the best 160m openings to JA he had heard in two years. The high-latitude K-index had been zero or one for each of that day’s three-hourly periods, which suggested a settled ionosphere for polar paths.

VHF and up:

It is looking like another week of unsettled weather with low pressure systems dominating the charts, bringing some wet and windy weather at times. There is unlikely to be much enhanced tropo on offer, but there could be rain scatter opportunities on the GHz bands. Last week saw rain scatter on 3.4 and 10GHz with signals from beacons, but sadly no UK activity to go with it.

Even light rain can provide enhancement if you look carefully for it, so make a noise on the GHz bands.