Propagation News – 14 April 2024

| April 12, 2024

The Sun is still looking a little bare, but the solar flux index has climbed back to 131, as of Thursday 11 April, with four active regions. The promise is that things will improve, especially as we will soon see the return of active region 3615, which was the source of numerous M-class and one X-class flare on its last rotation.

Things have been a little sparse on the higher HF bands, with only FT8 being audible or visible on the 10m band at times. Having said that there has been some good FT8 DX to be worked on the 10m band, including Angola, Malawi, China, Japan, Taiwan and the Solomon Islands.

During the recent solar eclipse event there were also a lot of US stations on the 10m band using WSPR. These included Bob, K6XX in Santa Cruz, California, who was copiable in the UK at around 1850UTC. This just shows how effective WSPR is as a mode on an otherwise quiet band.

There have been some early signs of Sporadic-E on the 10m band using digital modes, including some brief openings to Scotland from eastern UK. We can expect these to improve as we head towards May.

Next week, NOAA predicts that the solar flux index will be in the 140 to 150 range with a maximum Kp index of three. If this is correct it means that HF conditions will be roughly the same as last week.

VHF and up

The weather patterns are showing signs of change after being stuck for quite some time, and the main beneficiary will be VHF operators seeing a chance of Tropo returning to the bands.

The initial unsettled weather over the UK, with high pressure fixed over the continent, will take us through to the middle of the coming week.

Thereafter, a high will develop to the southwest of Britain midweek and drift northeast across the country, although some models take the high on a more southerly track. In either event, there should be some useful Tropo in the south and possibly northern areas too. This may be limited to southwestern areas for Tuesday’s 23cm UK Activity Contest, but will hopefully be more supportive of the 4m UK Activity Contest on Thursday.

Meteor scatter is worth a look next week since we are approaching the 21 and 22 April peak of the Lyrids shower at the end of next weekend.

The quieter solar conditions have taken aurora down the table, but it’s still good practice to watch out for, if the Kp index goes above five.

Gigahertz-band rain scatter certainly drops down the league table next week as high pressure probably takes over.

As we said earlier, the next big thing is the start of the 2024 Sporadic-E season, which slowly comes to life during April for the 10 and 6m bands, especially on digital modes, whereas the real shift up in gear often comes during May. As mentioned last week, it’s worth updating your list of beacons in your rig’s memory while it’s still quiet.

For EME operators, Moon declination is at maximum this weekend, ending the 14 April, so there will be long Moon windows. We are past perigee, so path losses are rising again. 144MHz sky noise is moderate this weekend then low for the rest of the week.

Category: GB2RS Propagation News