Propagation News – 22 September 2019
We had a relatively settled week, with the Kp index remaining at or below four. The high-speed solar wind was the reason for the K-index increase, but it didn’t significantly degrade HF propagation. We are seeing a change to more autumnal HF conditions with north to south paths opening up quite regularly. The summer doldrums are also now fading as we see an increase in daytime critical frequencies. This is probably the best month for working into the Southern Hemisphere.
A 10 metre FT8 opening at around 1500UTC on Monday saw the Falklands Islands being very workable. Mike, VP8NO and Bob, VP8LP were both active on the mode, giving many people a chance to get VP8 in their logs. South American stations active this week on 15 and 10m last week FT8 included Argentina, Brazil, Columbia and Paraguay. It does seem that a lot of DX stations have moved to FT8 and FT4 for contacts, a mode that works well under poor conditions due to its lower required signal to noise ratio. So if you haven’t tried it why not give FT8 a whirl? The Chilton ionosonde shows that daytime MUFs over a 3,000km path are now exceeding 18MHz and even touching 21MHz at times. There are also signs that limited sporadic E openings are still occurring on 10 metres.
Next week, NOAA predicts the solar flux index will remain pegged at about 68, with zero sunspots. Geomagnetic conditions will remain mainly settled, at least until the weekend of the 28th and 29th, when the Kp index may rise to six due to a solar coronal hole making its return after its transit around the Sun’s surface.
VHF and up
The coming week is looking like almost the exact opposite of last week. The high pressure systems will move away east by the start of this weekend and allow Atlantic lows to dominate the weather over the country for much of the coming week. This means any tropo at first to the east across the North Sea into the Baltic will soon fade and we’ll be left with unsettled, wet and rather breezy weather. As for propagation, there will be a chance of rain scatter on the microwave bands for Tuesday night’s Super High Frequency UK Activity Contest.
Other modes are always worth a look, even the odd fleeting bit of sporadic E on 10m perhaps. But it also worth mentioning that the autumn months are always a good time to be alert to the prospects of aurora.
The Moon reaches maximum declination tomorrow, and perigee on Friday, so EME conditions should be good all week with falling losses. Sky noise on 144MHz is mainly falling, but this coming Saturday the Sun and Moon are close together in the sky from mid-morning to moonset, so noise levels will make EME very difficult apart from for GHz band stations with very narrow antenna beam widths.
The daytime Sextanids meteor shower, with a zenithal hourly rate of five, peaks this coming Saturday, but is not a very big one. Continue to check the early hours before dawn for the best random meteors.
Category: GB2RS Propagation News
