Propagation News – 28 July 2019
Last week HF was once again dominated by sporadic E openings. On Wednesday FT8 contacts were being made across Europe on 28MHz, from Finland in the north to Spain in the south. It was a similar story on Thursday with S9 signals from the Balearic Islands to Norway. As we head towards August it is best to make the most of these, as the Es season will start to fade quite soon.
Other than sporadic E it has been quiet on the HF bands in general.
NOAA predicts that next week the Sun will continue to be spotless, with a solar flux index of 67. Geomagnetic conditions are likely to remain settled, with the Kp index predicted to be around two to three. The solar wind is currently more settled, with speeds down into the 300 to 400km per second range. However, a large solar coronal hole is making its way around the Sun. Its equatorial position means it is likely to have an impact on the Earth. Our best guess is that this could be mid-week, likely resulting in increased solar wind speeds, an elevated K-index and depressed maximum useable frequencies.
VHF and up
There is a warm, but unsettled theme to the weather in the next week, but like the last few days this hot weather can produce some very strong ducting over the seas around the British Isles. This means that tropo is always a possibility during this period. The unsettled nature of the weather is also going to lead to some potentially heavy showers on some days, bringing with them a chance of rain scatter.
We are still in the sporadic E season, so it’s always worth checking for openings. They tend to favour mid-morning, late afternoon or early evening. Follow the jet stream charts on the various websites—for example, propquest.co.uk—and use the daily blog to guide you as to which directions seem most likely to produce results. Sporadic E patches are created by the horizontal wind shear on the edges of these strong upper flows of air in the troposphere. These generate turbulence and launch atmospheric gravity waves up to the E region, where they produce vertical wind shear.
The Moon reaches maximum declination on Tuesday and perigee next Friday so it’s a good week for EME.
Another propagation mode to signal for attention is meteor scatter, with two small showers this week peaking on Tuesday. The Southern Delta Aquariids and the Alpha Capricornids are then followed by the major shower, the Perseids, in the next week or two, with a broad peak around 12 and 13 August.
Category: GB2RS Propagation News
