sabato 30 giugno 2018

Propagation News – 1 July 2018

As predicted, the geomagnetic K-index hit five last week, although it wasn’t until early morning on the 26th. Conditions then settled as the week progressed. The US Space Weather Prediction Center has the K-index remaining low for the week commencing Sunday, 1 July, so make the most of the settled geomagnetic conditions. Due to a lack of sunspots, the solar flux index may struggle to break 70 this week and may even be in the high 60s.

On a brighter note, the KH1/KH7Z Baker Island DXpedition in the Pacific is underway. While it is not an easy path from the UK, especially in summer, there are opportunities for a contact this week. Forget about the low bands as we have no periods of mutual darkness. It looks like 20m, 17m and 15m are the favourite bands. There is a slight possibility of a brief long-path opening on 12m or even 10m on long path in the early evening. Best times, in terms of maximum probability, are 1000UTC short path on 20m, 1900UTC long path on 17m, and 2000UTC long path on 15m. As both the short and long paths pass through the poles, look for quiet days geomagnetically with a low K-index. Needless to say, this is going to be tricky, but may be doable with higher power and a decent antenna. And don’t forget to try FT8, as they are trialling the new DXpedition mode.

VHF and up:

It’s another week with roughly the same set of weather charts, so expect tropo to be the mode of choice. Any sea path will perform well. Remember, the land paths are only usable under night-time conditions and early in the morning before the daytime heating destroys the temperature inversion.

Very often the UHF and microwave bands will perform best, so give them a try as well. Let’s hope that the recent excellent conditions stay around until next weekend’s VHF Field Day.

It’s another no-show for rain scatter, except for the extreme south where there is a risk, no more than that, of isolated thundery showers. That again leaves our high-summer mode, sporadic E, to play with. Like the past week, there will potentially be DX openings that make use of the meandering jet stream across northern latitudes to support paths to the Far East and North America. The more typical single hop paths within Europe are always a possibility and will depend upon the positioning of the ‘weather triggers’, which can be checked daily on

The Moon’s declination is negative until Friday and losses are still high. EME windows are for insomniacs this week, with the Moon up in the small hours and getting later as the week progresses.