venerdì 4 novembre 2016

Propagation News – 6 November 2016

Last week, the solar flux index remained in the mid to high 70s, but HF propagation was once again dominated by variable geomagnetic conditions. The first half of the week, which included the CQ Worldwide contest, was very unsettled with the K index at high latitudes peaking at seven. This drove down maximum useable frequencies and impacted a lot of potential DX contacts.

The second half of the week was a little more settled as a large coronal hole on the sun rotated away, but the K index was still four at times.

We should now see more settled geomagnetic conditions, at least until around the 8th or perhaps the 11th, depending upon which model you believe, when the K index will climb once again.

This is not expected to have much effect on LF, MF and HF over 2,000 to 3,000km paths, but may cause a reduction in signal levels particularly on longer, more northerly, paths that may persist for two or three days.

Otherwise, this is now a prime time for HF propagation, with worldwide contacts possible on all bands up to around 21MHz, with occasional openings on 12 and even 10 metres.
If you want a challenge, you still have a few days left to work the Six-Gs groups on Chatham Island who are operating as ZL7G.

After some welcome Tropo last week, we start this week with a low pressure system over the North Sea and a showery northerly across much of the country. Apart from a chance of some rain scatter on the Gigahertz bands, the VHF/UHF prospects seem likely to be uninspiring at first.

Soon after the weekend, we should find high pressure building back in across north-west Britain and this will gradually migrate to southern areas, leaving space for low pressure and a brisk westerly wind to reach the north again by the end of the week. During this period, as the high moves south, there is a prospect of some limited Tropo, especially in the south and across the near continent.

For meteor scatter enthusiasts, start preparing for the major shower for this month – the Leonids. It peaks on Thursday, the 17th, at around 1030UTC. Otherwise, it’s back to early mornings for random contacts on the low VHF bands.

Moon declination is at a minimum today and losses are high, but reduce as the week progresses, dropping to a minimum next Sunday.

Moon windows continue to lengthen as declination becomes positive again.