Propagation News – 26 November 2017
The Solar Flux Index remained in the 70s last week, reflecting the continued absence of sunspots. Geomagnetic conditions were unsettled at the beginning of the week, but improved as the effects of a coronal hole passed. We were left with a mixed bag of HF propagation, with fair conditions at times and poorer ones at others.
Highlights were the J5T DXpedition to Guinea-Bissau, and the Polish TO2SP DXpedition to St Barthelemy, with many radio amateurs filling much-wanted band slots. Other DX stations were on the air from around the world as they prepared for this weekend’s CQ Worldwide CW contest. Speaking of which, conditions seem likely to be fairly settled on Saturday, 25 November, but another earth-facing coronal hole looks as though it could threaten the ionosphere on Sunday, 26 November.
Saturday might be the best day for working DX in CQ Worldwide, whereas Sunday may be a little more unpredictable. If our prediction is correct, and solar matter impacts the Earth, there is the possibility of an initial HF enhancement, but then declining maximum useable frequencies as the K-index rises. Otherwise, expect 20 and 15 metres to be the main HF bands for DX, with good 10m openings being very thin on the ground.
Recently, some days have also seen some sporadic E responses on the ionosonde data, which can make a difference for local near vertical incidence skywave activity on 80m in the evening, when the foF2 ionisation is usually insufficient for inter-G nets. Since this may be related to jet stream activity, and there will be plenty of that this week, it’s certainly worth a check. You can monitor the ionosphere using the daily graphs available on www.propquest.co.uk.
VHF and up
The charts in both the primary longer-range models seem to be locked into a low pressure story for next week, which can mean quite windy and often colder weather too. There is little of cheer for the VHF/UHF bands in this pattern, except perhaps the odd bit of rain scatter as showers run down the coasts on northerly winds. Both models do suggest a build-up of higher pressure to the west of Ireland later next week and this may give some prospects for tropo as we move into the following week. But otherwise it is looking like thin pickings for weather-related propagation this time.
However, we are now into the build-up to what is often one of the better meteor showers of the year. The Geminids has a broad peak, culminating on 13 and 14 December, but there are normally many meteors throughout the shower period giving useful reflections. Unlike many meteor showers the Geminids is associated with the asteroid 3200 Phaethon, rather than a comet.
Minor shower Puppid Velids also starts around the end of this weekly report, with a peak around 9 December. Moonlight may affect shower visual sightings, but will not affect radio reflections. Talking of moonlight, the Moon is waxing gibbous this week with the half moon this evening, Sunday, and the full moon is next Sunday.
As we move into the latter half of the week the moon-path degradation is very low and better suited to smaller EME station operations. For those early birds, the morning moon will favour paths to the west, whilst the early and later evening moon will be better for paths to the east of the UK.
Category: GB2RS Propagation News
