Propagation News – 17 June 2018
It was more of the same last week with virtually zero sunspots, but some sporadic E to keep us amused on HF. We say virtually zero sunspots as a group had just appeared over the sun’s limb, pushing the sunspot number to 16 as the time of writing. This represents 10 for the single group and six for the number of visible spots in that group.
On Thursday afternoon the solar flux index was just 74 as the sunspots have not yet moved into an earth-facing position to have any real effect. NOAA doesn’t think they will not do too much for HF propagation, estimating the maximum solar flux index as 75 on Thursday, the 21st. The good news is geomagnetic conditions are predicted to remain fairly settled this week with a maximum K-index of two.
As we head towards the summer solstice the upper HF bands are remaining open later, which is the norm. The Chilton ionosonde suggests that 20 metres may be remaining open on 3,000km paths until around 11pm. But with the current low solar flux you may find 30 metres more reliable after dark on distant paths.
Meanwhile, sporadic E continues to impress, but may decline slightly as we head into July. So make the most of it. For those not familiar with sporadic E, it can generate very strong, localised, but often fleeting openings on HF up to 2,200km on all bands up to 10 metres. Also look out for rarer multi-hop sporadic E that can take your signals even further afield, as we’ll discuss in the VHF section.
Don’t miss the sporadic E openings, as it may be some time before we see reliable 10m band propagation again once the season has ended.
VHF and up
It looks as though there will be plenty of opportunity to talk about tropospheric openings during the next week, but northern Britain will have to cope with occasional periods of low pressure and stronger winds. On the positive side this may offer some rain scatter on the microwave bands. It is worth checking for this over this first weekend, even in the south where we may have some heavy showers around.
Back to the tropo now, and as a new ridge of high pressure builds in across southern Britain during next week, it will be a good option for longer VHF/UHF paths across Biscay and across the southern North Sea.
Stations in the far south-west should be alert for those rare but exciting openings down to EA8 and D4 if this tropo couples in to the Azores duct system.
Sporadic E is still in full season, and last week saw many QSOs from the UK into the Caribbean on six metres on both digital and CW. With the Atlantic jet stream over the country and a strong upper ridge over the near continent, there are good reasons to hope for some sporadic E into Europe and at times across the Atlantic. It may well be the turn for paths to Scandinavia as the jet stream over the UK moves over the Norwegian mountains by mid-week. If time is limited, check on 10m and 6m late morning and early evening.
June is one of the best periods of the year for meteor activity, so keep looking for meteor scatter in between the sporadic E openings.
The moon’s declination goes negative on Thursday, and the Moon is heading away from us again, but EME conditions will continue to be good throughout the week.
Category: GB2RS Propagation News
