Propagation News – 7 April 2024
Looking at the Sun on Wednesday 3 April, you might be forgiven for thinking we are near sunspot minimum!
With a near-total lack of sunspots and a solar flux index of 112, the solar disk was looking pretty bare. Compare that with just two weeks ago when the solar flux index was sitting at 209 on the 23 March.
But never fear, there seems to be some activity coming up. Two active regions, AR3627 and AR3628, have just rotated into view, but in the meantime make the most of the geomagnetically-quiet conditions.
10m propagation is still holding up, although you may find that the band opens a little later in the morning and shuts earlier in the afternoon. The 4X6TU and VK6RBP IBP beacons were both audible at 0945UTC on Thursday the 4th, while China, Japan, Mongolia and Thailand were copiable on 10m FT8, even with a lowish solar flux index.
Higher HF band propagation from the UK has moved from favouring North America to north-south paths, notably to South Africa and South America.
Next week, NOAA predicts that the solar flux index will rise a little, perhaps starting at around 135 and finishing at around 150. Geomagnetic conditions should be reasonably quiet with a maximum Kp index of 3, unless we get a coronal mass ejection that could send it soaring.
As always, keep an eye on solarham.net for current conditions.
VHF and up propagation
There have been reports of trans-equatorial QSOs on 144MHz from Southern Africa to the Southern Mediterranean, but here in the UK we can only dream due to our northerly location.
The next period of weather is unfortunately shaping up to be the same as most of the recent ones, dominated by low-pressure systems driving active weather fronts across the British Isles.
It means that Tropo conditions seem unlikely to feature much through to the end of the coming week. Rain scatter for the GHz bands remains the mode of choice with help from some heavy April showers. Meteor scatter options are still best with random meteors before dawn, but we are getting closer to the April Lyrids shower later this month, so not long to wait now.
The solar conditions have subsided a little recently, but we remain in scope for further activity, especially since April can be one of the more active months for aurora. Watch out for fluttery signals on HF or VHF bands, use the various clusters, or save the frequency of one of the northern beacons in your rig’s memory.
In fact, this is a good time to suggest updating your list of favourite beacons on the 10, 6, 4 and 2m bands since they’ll be useful for the upcoming sporadic-E season too.
It’s a good time to take an early look at the sporadic-E prospects before it gets properly busy.
Some background rules which may help are to use propquest.co.uk to see where the jet streams are, since Sporadic-E propagation is often associated with turbulence in regions of jet stream activity. Then look for a relatively low Kp index. The other main rules are related to timing. Usually, there are two windows of opportunity, one in the morning and a second in the late afternoon or early evening. However, at the beginning of the season, these are approximate.
Sporadic-E starts on the lower bands like 10m and, if strong enough, will gradually extend to the higher bands. The 10 and 6m bands are probably the ones to check this month.
For EME operators, Moon declination goes positive again on Sunday, which is also Moon perigee, its closest point to Earth, so we’ll see lengthening Moon windows, increasing elevation and low path losses. 144MHz sky noise is low until Monday’s total solar eclipse, then moderate for the rest of the week.
Category: GB2RS Propagation News
