Propagation News – 27 January 2019

| January 25, 2019

This week we did get a new sunspot group, which pushed the solar flux index to 71 and the sunspot number to 18, reflecting one group with eight spots in it. But, as predicted last week, incoming matter from a solar coronal hole resulted in an elevated K-index and poor HF conditions on Wednesday, the 23rd. Because of this, maximum usable frequencies were depressed and struggled to reach much more than 14MHz at times. Late Wednesday afternoon even saw 40m closing early.

Despite a continued K-index of four on Thursday, MUFs did manage to recover slightly and signals were heard on many HF bands. This included an opening around Europe and out as far as Israel and Cyprus on 10m FT8, which may have been due to a pre-auroral enhancement.

There were other highlights during the week. Andy, M0NKR reported working E51DWC on the South Cook Islands on 20m CW on Monday afternoon at about 5.30pm, which just goes to show you shouldn’t write the bands off.

Next week NOAA has the solar flux index remaining at 71, with generally quieter geomagnetic conditions, at least until the Thursday, the 31st. This may then herald three days of unsettled conditions due to a recurrent coronal hole.

As always, don’t neglect the upper HF bands, especially at the onset of a geomagnetic storm, as these can often bring short-lived openings on the higher HF frequencies.

VHF and up

It’s shaping up to be another rather flat week for tropo, although it’s always possible to get some limited surface ducting in the early mornings with this cold frosty weather and patchy fog. Much of the coming week is dominated by low pressure and, at times, brisk winds, which will rule out traditional tropo options. That probably leaves, like last week, just a few chances of some rain scatter on the GHz bands. Snow however does act as a very good scatterer on these bands.

Keep a watch for the other exotic modes, like out-of-season winter sporadic E or some auroral QSOs. What about trying some flat condition path checks to see how your station is doing, by calibrating against a selection of beacons or repeaters, so that you have a baseline to compare against when the high pressure systems do return? Incidentally, you could even try a late New Year resolution to activate CW on the VHF/UHF bands. You never know, flat conditions can provide more than you think.

Moon declination is negative again and reaches minimum next Saturday. Moon windows will shorten as the week progresses and maximum Moon elevation will be in the early mornings, so it is a week for EME early-risers.

We are still in the doldrums as far as meteor showers go with just a couple of minor ones in February and March until the April Lyrids.

Category: GB2RS Propagation News