Propagation News – 23 January 2022
We had a bit of a geomagnetic roller coaster ride this week. The Kp index was down as low as one, and up as high as six, which sparked visible aurora at northern latitudes. This was caused by a solar wind stream, which reached nearly 600km per second and contained a significant southward Bz component. This meant that it more easily coupled with the Earth’s magnetic field, allowing the plasma to flow in.
With regard to sunspots, we had a decline in sunspot numbers as the week progressed as the more active regions rotated off the visible disk. So ionospheric propagation was a mixed bag last week, buoyed by sunspots, but adversely affected by the raised Kp index. However, there were 10m openings to Australia and Malaysia reported by CDXC members, and other 10m openings into Europe noted on Monday the 17th. Indonesia also put in an appearance on 10m FT8 on Tuesday, according to Chris, 2E0EEY on the 10m UK Net Facebook group. As always, keep an eye on the upper bands, where you may get the odd surprise.
Next week, NOAA predicts that the solar flux index will continue to decline, perhaps starting at 102 and potentially finishing in the low 90s. But geomagnetic conditions are predicted to be more stable, with a maximum Kp index of two or three for most of the week.
And finally, there appears to be a problem with the data feed for the Propquest foF2 critical frequency graph data from the USA. The graphs will return as soon as we start receiving information again.
VHF and up
The coming week once again looks dominated by high pressure over the country, with some good Tropo prospects. Also, like last week, the high centre may become displaced just to the west to allow a showery northwesterly in across Scotland and eastern England, thereby reducing the Tropo for the eastern side of the country at times. As a general rule, long-lasting highs can provide some good options for DX Tropo 1,000 to 2,000km along the side of the high pressure area, but aiming through the centre may be risky since the temperature inversion often descends to the surface and ducts the signal into the ground.
Other propagation modes are also worth a look, or at least it’s worth getting a list of useful beacon frequencies at the ready. If activity is low, check what’s doing on FT8 or MSK144 meteor scatter by calling CQ and using the PSKreporter website – which you can easily find via Google – to see how far you are getting.
As we are in the annual low period of meteor activity, random meteor scatter will be hard going unless you stick to the pre-dawn period. In view of the solar activity recently, perhaps there’s a chance of an aurora.
Moon declination goes negative again today, so Moon windows will shorten. With perigee a week away, path losses are low and falling so that’s good for GHz bands EME, but Moon time will be limited due to the negative declination. For VHF EMEers, 144MHz sky noise starts low this week, but increases, hitting a peak of over 3,000 Kelvin next Saturday.
Category: GB2RS Propagation News
