Propagation News – 13 February 2022
We had a good week for HF propagation, with a solar flux index up towards 130 and relatively calm geomagnetic conditions. There were lots of reports of openings to Australia on 10 metres and the KQ2H repeater in up-state New York often put in an appearance on 29.620MHz FM as well.
However, a Coronal Mass Ejection following a filament eruption on the 6th of February impacted the Earth on Wednesday the 9th. The solar wind speed showed only a small increase, while the Bz component of the interplanetary magnetic field, or IMF, was fairly neutral.
The net result was that the CME had little effect at first on the ionosphere and only resulted in a Kp index of three, despite dire forecasts in the national press of aurorae perhaps being visible from the UK. But, by 1500UTC on Thursday, the IMF had taken a sudden and swift shift southwards and the Kp index rose to five. Which just goes to show how hard it is to be precise with regards to timings about geomagnetic events.
Critical frequencies continue to exceed 7MHz during daytime, which bodes well for inter-G contacts.
Next week, NOAA predicts that the SFI will decline slightly to around 115, which hopefully should still be enough to provide openings on 12 and 10 metres. NOAA also predicts a Kp index of five on Monday, probably as a result of a returning coronal hole. Other than that, the rest of the week looks relatively calm.
As we head towards mid-February we are starting to see North-South paths opening up a little more. This will improve as we head towards the Equinox in March. But for now, look out for openings to South America on 10 metres, perhaps later in the day as the Sun is setting.
VHF and up
The Tropo from lengthy spells of high-pressure weather is now some time in the past and it’s hard to see a return anytime soon. In fact, the nearest high pressure systems are out of reach to the south of Britain and the UK will find a sequence of low pressure systems bringing wet and very windy weather with heavy rain and even some snow in places. This is hardly conducive to Tropo, so once again we must turn to other chance modes such as aurora and random meteor scatter.
It is also worth saying that even though we assume this to be a quiet period for Sporadic-E, there have been some days when the critical frequency of the Sporadic-E layer, or foEs, has peaked at 6MHz. See the NVIS tab on Propquest.co.uk graphs for Chilton on the 8th of February. It would make it worth checking for short skip on HF and, if repeated farther afield, perhaps some strong European signals on 10m. These foEs events appear to be found on the maps near to strong upper winds, known as jet streams, and these will be plentiful over the next two weeks with such unsettled weather, so it is worth checking the beacons and clusters for chance openings.
Moon declination is high, but falling all week, going negative again next Saturday. Moon windows will therefore follow suit and shorten as the week progresses. Path losses will fall as we are now past last Friday’s apogee. For VHF EMEers, 144MHz sky noise is low throughout the week, only rising above 300 Kelvin next Saturday.
Category: GB2RS Propagation News
