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HF News
As we enter October, I think it’s time to get excited about HF again. Some of the best HF conditions can occur this month as MUFs rise. It might take a couple of weeks to get going, but it will, I promise – there’s a good reason why the CQ Worldwide SSB contest is held in October after all.
Solar conditions have been surprisingly calm. The solar flux index has been ranging from 90-100, but geomagnetic conditions have been quiet, with the Kp index usually around one to two. We had a brief excursion to Kp=4 on September 26 and 27, but this was relatively short-lived.
Daytime MUFs over a 3,000km path have been touching 25-28MHz at times, but we can expect this to improve over the next few weeks. As long as the SFI can stay around 100 we should see some transatlantic paths opening up on 28MHz, but they may not be as good as previous years. Ten-metre openings at the start of this month may be fleeting and unreliable.
What we do have is a massive coronal hole on the Sun’s equator, which could send the Kp index up this weekend as solar plasma impacts the Earth. Keep an eye on solarham.com for updates. If this comes to pass, expect lower MUFs and poor DX for a day or two.
DX to be worked this week includes 5W0AF (Samoa), 9T0MD (Democratic Republic of Congo), JW6VM, JW7XK and JW9DL (Svalbard), 7P8JL, 7P8LZ and 7P8TR (Lesotho), 6O2M (Somalia), C5R (The Gambia) and FW1P (Wallis and Futuna).
NOAA predicts that the SFI this coming week may bottom out at around 90, before rising again, perhaps reaching 100-102 by next weekend. As mentioned earlier, we can expect the Kp index to rise, perhaps hitting four on October 5 to 7. After this, it should settle to a more reasonable Kp=2 for the rest of the week.
VHF and up
The autumn season is typically a mix of still, quiet weather with high pressure on the charts and, in contrast, a few days later deep Atlantic lows roll by with wind and rain. The coming 10 days or so will follow that script and offer a mix of propagation modes for the VHF/UHF fraternity. The Tropo conditions will dominate in the south and should probably be in control up to the middle of next week. Northern Britain will have activity from weather fronts and possible rain scatter for the GHz bands, which becomes more general from mid-week onwards.
The autumn season is also a prime time for aurora, so keep that mode on the ‘to do’ list and be aware of changes in the Kp index to values higher than Kp=5. Meteor scatter is mostly in the realms of random activity.
Lastly, a surprise mention of Sporadic-E, which for CW and SSB modes, is pretty much done, but last week on Thursday 24th September there was some activity for FT8 within Europe. This was mixed in with Tropo paths, so it was difficult to pinpoint the exact mode being used without looking at detailed measurements from radiosondes and ionosondes. The end result is that ‘out of season’ may still produce Es for digital modes, but it’s probably a rare occurrence.
EME now, and the Moon is at maximum declination on Friday the 2nd of October, so Moon windows are at their longest and peak Moon elevation is at its highest. Path losses are low after perigee on October 1st, but will start to increase. 144 MHz sky noise starts the week moderate, dropping back to low for the rest of the week.