venerdì 10 febbraio 2017

Propagation News – 12 February 2017

Last week, the hoped-for settled geomagnetic conditions materialised, but could have been better. After Monday, the K-index settled down to one or two for the rest of the week.

HF conditions have been variable, rather than outstanding. There have been some 15 metre openings at times, but 20 and 17 metres have been more consistent. The lower bands, such as 80 and 40 metres, have also been proving how good they can be in the winter, offering DX at times.

The daytime critical frequency has been reaching around 6MHz, meaning 40m is open to slightly longer skip of 500 to 1,000 kilometres. Sixty metres has been better for daytime inter-G contacts. The estimated nighttime MUF over a 3,000km path has been staying above 7MHz through the night.

Next week, the solar flux index is predicted to remain in the 70s, moving higher towards 80 around the eighteenth.

Geomagnetically-settled conditions should continue until around the fourteenth, when the K-index is predicted to rise to four, due to recurrent coronal hole activity. But this should be relatively short lived.

We will be moving towards springtime HF conditions in a few weeks, so make the most of the better low-band conditions while you can.

VHF and up:

With high pressure over the North Sea and the nearby continent, we might expect some enhanced tropo conditions on paths across to Denmark and northern Germany later this weekend, but nothing major.

Some weather models bring the high a bit closer at the end of next week. This may limit the tropo by lowering the temperature inversion and bringing very dry air from the continent, degrading the inversions’ ability to generate tropo. So, a slightly better week than last, but much of the time there will be no major tropo event.

Even with poor tropo conditions, it’s worth investigating the VHF, UHF and GHz bands. There are always DX opportunities at VHF and above using aircraft scatter—up to 800km if you have the right equipment to take advantage of short duration paths. Digimodes or fast CW are required.

We are in the winter minimum of meteor activity, but there are still opportunities for random meteor scatter contacts around dawn, when the Earth is rotating into the flux of meteoric particles.

Moon declination is falling, going negative on Tuesday, and losses are increasing. With apogee only a week away, the best conditions for EME contacts will be early this week.