Once again the sun looks pretty spotless, apart from one tiny smudge. As a
result, this week saw the solar flux index drop below 80. We’re beginning to
sound like a stuck record, but ongoing coronal hole activity pushed the K-index
to five on Wednesday 22nd. Noisy electrical storms across most of northern
Europe didn’t help the bands either.
Next week the USAF predicts the
solar flux index will be in the range 70-80, with the potential for unsettled
geomagnetic conditions on Saturday the 2nd and Sunday, 3 July. As the solar flux
index at sunspot minimum doesn’t fall below about 66, this gives you some idea
of the current state of the sun.
As it is mid-summer we can’t expect
fantastic HF conditions either, with lower maximum usable frequencies during the
day, compared with the autumn and winter, but higher MUFs at night.
If you want a challenge, try
listening for the Alexanderson alternator at station SAQ in Grimeton, Sweden on
17.2kHz CW at 0900 and 1200UTC on Sunday, 3 July. The Twente SDR on the web can
cover 17.2kHz, or you can hook an antenna up to your sound card and use some
specialist software. Amateur station SK6SAQ will also be active on 80m SSB and
40, 20 and 15m CW during the day.
VHF and up propagation
news:
Sporadic-E may be poorer next week
as the main Atlantic jet stream activity has already migrated north, leaving
much of central Europe under a much slacker pattern. The absence of active jet
streams over Europe probably means that one of the main sporadic E triggers,
gravity waves, may be missing or reduced. These waves propagate up from the
turbulence of the jet stream at 12km height to the E region at 120km.
This absence will make sporadic E
hard to come by except perhaps for the more northern paths across to Scandinavia
where the jet stream may be slightly more active.
Next week we will find a big high
with a very large east-west extent just north of the Azores and covering much of
the Atlantic. This could give some interesting tropo paths down the western side
of Europe from the UK to Spain and Portugal and onwards to the Canaries or Cape
Verde.
It may also be a tempting week for
those seeking the more unlikely options of transatlantic tropo. This is very
much a long shot, since there are fronts involved which can easily break any
ducts.
Moon declination goes positive on Monday and losses are falling
with perigee on Friday, so EME conditions will improve as the week
progresses.
RSGB
