venerdì 6 luglio 2018

Propagation News – 8 July 2018

The 2018 Baker Island DXpedition has now concluded. As we said last week, the path from the UK to the Pacific is a difficult one, but plenty of UK amateurs did manage to make a contact with KH7Z. Twenty and seventeen metres did indeed prove to be the best bands, but on the whole it was only better-equipped stations with beams and linear amplifiers that made it. There were some exceptions – Ian, G4IIY in Cumbria managed the contact with 100W CW to a quarter wave vertical. With a solar flux index under 70 and a polar path it was never going to be easy, but a low K index representing settled geomagnetic conditions helped a lot.

A small equatorial coronal hole became Earth-facing on Thursday the 5th, so we can expect the possibility of unsettled geomagnetic conditions on Saturday 7th and Sunday the 8th. Otherwise, NOAA predicts settled geomagnetic conditions for the rest of the week. The solar flux index is likely to remain around 68 for the first half of the week as the sun remains spotless, but is predicted to rise to around 75 in the latter half.

F2-layer MUFs continue to struggle much above 18MHz on 3,000km paths during the day, but can remain above 7 and even 10MHz at night. We can expect to see continued Sporadic-E, which can bring short-skip on all HF bands at times. Do keep an eye on 10 metres for Sporadic-E openings, especially the CW beacons that run from about 28.160 to 28.325MHz. And if in doubt, call CQ – you never know who might come back!

It’s another week of high pressure, with a few minor adjustments to the weather maps. This may provide plenty of Tropo during the coming week, especially around the coast and across sea paths. Remember that the best time for overland tropo propagation is from sunset, and overnight until just after sunrise the following morning, so get on the bands after supper and before breakfast for the best chance of DX openings.

There will be a few showers in the next week, especially in the south and west, but these will be fairly well isolated, so any microwave band rain scatter options will be limited.

Sporadic-E is still available through July into August, and perhaps early September in some years, although it can be a bit fickle. Using the clusters and web sites, such as dxmaps.com or ON4KST.com, is a great way to get a flavour of activity and the paths currently on offer. The best times are usually late morning and late afternoon/early evening.

There are no major meteor showers this week, so get on early in the morning for the best random meteor scatter conditions. It’s worth noting that with tropo, meteor scatter and to some extent Sporadic-E, DX on VHF and up suits those who have to do a normal working day!

The new lunar month is under way again, with positive and rising declination and falling losses up to the Moon’s perigee on Friday morning. But be aware that the sun is close to the Moon early on Friday, so solar noise levels will be high. That said, it is a good week for EME.