Propagation News – 10 April 2022
We had another week of high-ish solar flux numbers, but this time we had relatively settled geomagnetic conditions that really allowed the ionosphere to play ball for radio amateurs.
The week started well with the SFI above 140, which then declined as the week went on and was at 117 on Thursday. The maximum Kp index was four on Sunday and Monday, which then declined to one and two as the week went on, before going back to four on Thursday. It looks like the faint CME generated by a filament eruption on the 3rd of April did not reach Earth, which was a bonus.
A new report from NASA has confirmed that Solar Cycle 25 is racing ahead of the official forecast and the gap is growing. Sunspot counts have now exceeded predictions for 18 straight months. The monthly value at the end of March was more than twice the forecast, and the highest in nearly seven years. The Solar Cycle Prediction Panel predicted that Solar Cycle 25 would peak in July 2025 as a relatively weak cycle, but instead, the cycle is shaping up to be stronger.
Conditions have been quite good with many reports coming in of DX on the HF bands. John, G4BAO reports that 10m has been rocking this week. There have been daily morning openings to Asia and Australia, plus South America and the Caribbean later in the day.
And Chris, G1WSA reports 20m QSOs with N3SJL and then VK7RG. The interesting part is that Chris was only using a short Diamond HF20FX 1.2m whip on a mag mount on his car.
Next week, NOAA’s prediction has the solar flux at 115 for most of the time, perhaps rising to 120 as the week progresses. A small Earth-facing coronal hole might spell unsettled geomagnetic conditions this weekend, and NOAA forecasts unsettled geomagnetic conditions for the 11th and 12th with a predicted Kp index of four.
So possibly more of the same next week – try to make the most of the good HF conditions.
VHF and up
Last week ended with a cold northerly wind, but with developing high pressure for the weekend a chance of some Tropo, although in cold and often dry air like this, it is rarely very effective.
As we move into the new week a slow-moving front drifts across the country from the Atlantic with some rain and perhaps a hint of rain scatter where the front breaks up into showery bursts of rain in southern Britain. The rest of the week will be largely controlled by slack ridges of high pressure, despite a temporary weak front reaching northwest Scotland for a time.
The weak ridging probably develops further into the Easter weekend with a region of high pressure over the country. Some models hold the new high farther south over France and may allow further fronts to edge into Scotland.
The usual bonuses of random meteor scatter and aurora are still in play given the right circumstances, as is the arrival of some early Sporadic-E as we move into the second half of April.
This could be aided by a very busy upper air pattern offering plenty of jet streams, which can be associated with Es formation regions. Check out 10m first and then 6m, especially for data modes.
Moon declination is at maximum this weekend and declining as the week goes on, so again, Moon windows are long and peak Moon elevation will be high. Apogee was last Thursday so path losses will decrease throughout the week. 144MHz sky noise is low all week, reaching a minimum of 174K on Monday.
Category: GB2RS Propagation News
