Propagation News – 30 January 2022
It’s good news this week as it looks like we might get some more sunspot activity. Last week was characterised by relatively low sunspot numbers and a solar flux generally in the high 90s. We had quite a bit of solar flare activity, but luckily any associated coronal mass ejections tended to be away from Earth. Nevertheless, the solar wind remained strong, with speeds over 450 kilometres per second being commonplace. The solar wind density remained low though, and the Bz was mostly positive, which probably explains why the Kp index never really got above three.
Critical frequencies often got above 7MHz during the day bringing short-skip contacts around the UK on 40m at times. Maximum Useable Frequencies over a 3,000km path often touched 28MHz, especially around lunchtime.
NOAA predicts that the solar flux index may increase this week and may enter the range 100-110. While this is not as high as we would like, it is a step in the right direction! Geomagnetic conditions will remain mainly calm, until the 4th of February when the Kp index is forecast to hit five. Two active regions can be seen in the STEREO Ahead spacecraft imagery and are due to become visible from Earth in the next day or so. Let’s hope they develop into decent sunspots.
And a reminder that we are now entering turbulent times. More sunspots mean more chance of solar flares and coronal mass ejections, which are both detrimental to HF propagation on the whole.
And finally, some good news. The data feed to the Propquest website is now fixed so you can see near-real time readings of the critical frequency and predicted MUFs over varying path lengths again.
VHF and up
It’s a case of “Negative Waves” for propagation this coming week, with a change to more unsettled weather. With pressure falling rapidly as this report was prepared on Wednesday evening, the high has been taking quite a knock recently and it’s now displaced to the south and west. This allows a series of lows and frontal systems to move southeast across the UK, affecting the eastern side more than the west.
Whatever else it means in terms of rain or snow and stronger winds, it has already dismantled the UK-wide Tropo conditions and it’s going to be hard to find much cheer in that department, except perhaps from southwest England to France and northern Spain.
Unsettled conditions like these may offer some rain scatter, but not a strong chance in the winter months.
That leaves us with occasional auroral moments and any random meteors that happen to pass by. But as we pointed out last week, we are in the annual low period of meteor activity, and random meteor scatter will be hard going unless you stick to the pre-dawn period.
Moon declination is at its minimum this weekend, so Moon windows are at their shortest. We are at perigee, meaning path losses are at their lowest; good for GHz bands EME, but Moon time will be very limited and all at peak elevations below 30 degrees until Friday.
For VHF EMEers, 144MHz sky noise is low throughout the week, but of course the low elevation means high horizon noise.
Category: GB2RS Propagation News
