Propagation News – 22 November 2015

| November 20, 2015

This week has been a bit of a mixed bag in terms of HF propagation. The early part of the week saw reasonable openings on 18 and 21MHz, although a continuous K-index of around three due to the high speed solar wind stream, took its toll. The VK9WA Willis Island DXpedition was even audible on 40m with a simple dipole around teatime on Wednesday.

But overall, DX signals were never brilliant and the bands had a tendency to be noisy.

Very late on Wednesday evening plasma from a coronal mass ejection arrived on Earth, pushing the K-index to five. As a result Thursday saw the bands noisier still, although the maximum useable frequency at noon remained around 26MHz according to the Chilton ionosonde.

Next week we expect more of the same with the solar flux index in the range 105-115. The K-index is expected to be in the range two to three, showing reasonably settled geomagnetic conditions that may bode well for next weekend’s CQ Worldwide CW contest.

As ever, be prepared for a sudden elevated K-index due to the effect of the high speed solar wind, which can be difficult to predict.

VHF and up propagation news

Things are looking flat for VHF/UHF propagation again next week. The charts suggest low pressure will not be far away from the north of Britain with strong west or south-westerly winds at times. There are unlikely to be any significant tropospheric openings to get excited about, but last week saw some good rain scatter propagation on the gigahertz bands.

With strong shower activity around coastal areas, and along the English Channel on some days, there will be scope for more of the same this coming week. Unlike summer thunderstorms, which can be very heavy and slow moving, winter showers are often fast moving in the strong upper level steering winds. Up to 30 to 50mph is possible, so you’ll need to track your dish to keep up with them. They are also shallower, so you’ll need to be closer than is the case with the deep convection of summertime.

The Leonids meteor shower is over so it’s back to early morning random QSOs for meteor scatter enthusiasts, while we wait for the major Geminids shower in December.

This is a good week for EME operators, with the Moon reaching perigee, or its closest point, losses will be low tomorrow and increasing declination means moon windows will be long.

Category: GB2RS Propagation News