Propagation News – 26 July 2015

| July 24, 2015

This week had seen reasonably settled conditions until the geomagnetic Kp index hit five on Thursday 23rd, thanks to a glancing blow from a solar coronal mass ejection. The solar flux index fell below 100 as well. If we look at the smoothed solar flux and sunspot data we can see we are now exiting the second peak of solar cycle 24 and may very well be in the early stages of a slow decline to the next solar minimum. However, this does not mean that we have seen the last of large sunspot groups and solar flares. Spikes in activity will remain likely while the sun makes the long transition to the solar minimum around 2019-2020.

Meanwhile there is DX to be worked—if you know where to look!

The sun is currently looking pretty bare and the USAF forecast is for the solar flux index to remain in 100-110 range next week. Geomagnetic conditions are predicted to be quiet with low A and K indices.

Summer daytime ionospheric absorption continues to impact the HF bands, but the evenings from 2100UTC and night time are proving fruitful, especially for contacts to the Caribbean and South America on 17 and 20m.

VHF and up propagation news

It looks like a disappointing week if we expect the weather to help with VHF propagation. For much of the time there will be low pressure close to the British Isles. This may provide heavy showers so some upper GHz bands rain scatter propagation is likely. Early in the week may see North Sea tropo, but only for coastal stations. Stations in the far south-west may still get paths down to northern Spain. Later, there are signs of rising pressure as a small high builds towards Britain towards the end of the week.

Sporadic-E events are likely to tail off now as we move into August, but it can still be a useful provider of new squares and DXCCs for 4 and 6 metres. Try the late morning and late afternoon/evening periods to capture the best chance of being there at the right time.

The countdown to the main meteor shower of the year, the Perseids, begins now. The peak should be around 12 August, but the broad peak means that meteor scatter will gradually become more important over the next couple of weeks.

The moon reaches its lowest declination on Wednesday, but EME path losses are falling and will reach minimum as the moon reaches perigee next Sunday.

Category: GB2RS Propagation News