venerdì 15 maggio 2020

Propagation News – 17 May 2020

RSGB
May 15, 2020

We had another week dominated by sporadic E openings. While the Sun remained quiet with zero sunspots, sporadic E proved to be the major mode of propagation. It offered both single and multi-hop openings, with 10m being open to Spain, Portugal and beyond on most days. Likely multi-hop paths have seen openings to Chad, Mauritania, St Lucia and further afield. On 20m and 15m there have been F2-layer openings to the Far East, Hawaii, Alaska and South America reported, although most of these have been on FT8 by well-equipped stations. An easier catch for Chris, G3SJJ was C31CT in Andorra who “popped out of the noise” on 17m. This shows the importance of monitoring the bands and watching the cluster for those elusive short HF openings.

Next week NOAA predicts that the Sun will likely remain spotless with a solar flux index of 68-70. On Thursday a polar coronal hole with a long finger pointing towards the solar equator was likely releasing a high-speed solar wind stream. This could result in unsettled geomagnetic conditions over the weekend. NOAA predicts the Kp index could rise to three on Monday, the 18th.

VHF and up:

The weather models are showing a mainly high-pressure week and therefore there should be some good prospects for tropo. Since the high does not have a great source of moist air underneath the inversion, the tropo may be less than ideal. However, the position of the high over this weekend may allow better tropo conditions across southern Britain and across the Channel into France. The north and west of the UK are going to be close to fronts on several occasions next week, and on Monday a weakness in the high may allow a few showers to develop and bring some rain scatter on the GHz bands. One of the models does break the high pressure trend and bring a deepening low past north-west Britain in the second half of next week with further rain scatter possibilities.

We have seen a good number of sporadic E days in the last week, especially for digital modes, but CW and SSB have produced results too. The position of the jet streams suggests that Scandinavia, the Baltic and northern Europe may be the preferred regions of interest next week. Check the beacons and clusters for signs of activity, and keep QSOs short, since conditions can change suddenly from an easy 5/9 to lost in the noise.

We should see the start of the Arietids meteor shower this week lasting from 22 May until 2 July, peaking on 7 June. Moon declination is increasing again, going positive on Monday but this coincides with apogee, so path losses are at their highest. 144MHz sky noise is low apart from Friday afternoon where the Sun and Moon are close to eclipse. (rsgb.org)