venerdì 16 giugno 2017

RSGB Propagation News – 18 June 2017

Last week, the solar flux index stayed steadfastly in the mid-70s. After Sunday the 11th, geomagnetic conditions were also reasonably settled, with the K-index mainly around one or two.

The big HF news this week has been the ongoing sporadic E openings. These have affected all the HF bands, but are particularly noticeable on 10 metres. A sporadic E cloud over the UK on the 9th resulted in G0KYA in Norfolk even working Mike, G4XRR in Weymouth on 10m SSB. This is very short skip, even for a sporadic E opening.

Next week, NOAA predicts the solar flux index will be in the low 70s, but geomagnetic conditions may be unsettled this weekend due to a series of coronal holes. Conditions should be more settled as the week progresses.

Apart from sporadic E openings, do keep an eye on 14MHz, especially during late evening, as the band often throws up some interesting DX via F2 layer openings. In summer, 20m stays open much longer than in winter and can often be better in the evening, once D-layer absorption has died down.

JT65 is also proving very popular for DX, especially for amateurs who can’t put up extensive antennas or who prefer to run low power.

VHF and up:

Early next week will be dominated by high pressure, lasting until at least midweek. The main emphasis is for the south of the country to be closer to the high initially, but in one model this transfers to northern Britain by the end of the week. This will offer many areas some summer tropo conditions and, in particular, fair prospects within the UK overnight and first thing in the morning until the daytime heating breaks down the surface temperature inversion. The bias of the high to the south should also offer some paths from southwest Britain across Biscay to northern Spain.

The point of doubt in the coming week would appear to be the security of the high after midweek. One of the models brings in a showery trough, and eventually a slow-moving area of low pressure, which could mean thunderstorms and some rain scatter on the GHz bands if it turns out to be correct.

As we said in the HF report, June is high season for sporadic E. There have been some good openings in the last week and should be again next week, although as the high builds, prospects may quieten down a bit.

EME prospects improve this week, with declination going positive today and losses falling as the week progresses.

The June Bootids and Beta-Taurids meteor showers are active this week but the zenithal hourly rate, a measure of the shower’s meteor rate, is fairly low from both.