Propagation News – 12 February 2023

The solar flux index rose again this week with the arrival of more sunspots. By Thursday, the SFI had reached 192, up from 135 the week before.

However, there has been some flare activity with minor C-class and some M-class flares, mainly from active region 3213. None of these have erupted in an Earthward direction so we’ve avoided coronal mass ejections and their effects.

The solar wind has been quite active, including long periods with a negative Bz and speeds of up to 600 kilometres per second. This has meant that the Kp index has remained relatively high, hovering around 3.5 for days.

All of this means that ionospheric conditions have been quite good with the daytime critical frequency over the UK generally above 9MHz. This means that paths over 3,000km have generally supported operations up to and beyond 10 metres.

At night, MUFs over 3,000km hover around 10MHz, especially in the hours just after sunset.

Next week, the US Air Force has the SFI remaining at around 195, before falling back to 150 by 17 February. Geomagnetic conditions should remain relatively settled, unless we get a coronal mass ejection.

All in all, this is a good time for HF so get to it! And good luck with making contact with the 3Y0J Bouvet Island DXpedition.

VHF and up

The large area of high pressure which has brought tropo to many parts of the British Isles looks good for a few more days. Some models suggest that Atlantic lows may move in after mid-week, so make the most of it before then.

Unfortunately, the northern parts of the country have seen windier weather at times and largely missed out on the best tropo, although with some chance of rain scatter to make up for it.

The aurora prospects and meteor scatter are still worth a check during the next week. Check aurora when the Kp index is high, and meteor scatter around dawn. Use the usual sources of information, such as clusters and band reports to get onto the bands at the right time.

For EME operators, Moon declination is negative, reaching a minimum on Thursday. EME Moon availability windows will be short. Path losses are at their lowest as the Moon approaches perigee next Sunday.

144MHz sky noise is moderate at the start of the week but increases to a high of over 3200 Kelvin next Thursday 16 February.

Category: GB2RS Propagation News