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Propagation News – 14 March 2021

The bulk of last week saw settled geomagnetic conditions. Wednesday saw the Kp index at zero for much of the day, which is unusual. This was mainly due to a lack of disruptive coronal holes on the Sun’s surface, so the solar wind speed was mainly below 400 kilometres per second. The Sun was relatively spotless and at the time this report was being prepared, region 2807 was disappearing around the Sun’s edge, while region 2808 was appearing around the North-Eastern limb. Another tiny spot has appeared around the middle of the visible disk, but it doesn’t appear threatening and is likely adding very little to the solar flux index.

The highlight of the week was probably the ARRL DX SSB contest last weekend, which saw plenty of stateside stations being worked. Chris, G0DWV said he worked California on 20 and 40m, plus Washington and Oregon. In fact, the only two states he didn’t work on 20 metres were New Mexico and Utah.

A slender coronal hole, reaching up to the solar equator, looks like it could cause some disruption this weekend with the Kp index predicted to rise to four. NOAA predicts the solar flux index will rise from 70 on the 14th to 76 on the 21st. Don’t expect the quieter geomagnetic conditions to continue though. It will probably be a roller coaster ride next week, with the Kp index predicted to climb to five on the 18th and 19th.

We said that it would be nice to have some more sunspots for this weekend’s 84th annual Commonwealth Contest, but it looks like we could be disappointed. But don’t despair, it is not unusual for stations from around the world to make an appearance, including many from Australia, New Zealand, Canada, the Caribbean, and more. The bonus is that there is no competition from DX hounds in non-Commonwealth countries.

VHF and up:

A stormy end to this week, but signs of another spell of high pressure next week. Stormy weather with its rain and blustery showers could be useful for some rain scatter on the GHz bands. The intensifying high should bring Tropo back on the menu as the week progresses and will also mean some quieter weather to repair any antennas that have suffered in the recent gales. This particular spell of high-pressure weather extends from the south-west, so it probably has moist air trapped under the inversion compared to a cold air high from the north and this could produce better Tropo conditions.

We are still in the doldrums regarding Sporadic-E, but we are moving towards the spring months and April, and especially May, can bring some early Sporadic-E events, especially for those using digital modes.

Moon declination goes positive tomorrow so Moon visibility windows and peak Moon elevations will increase as the week progresses. As we approach apogee on Thursday, path losses will reach a maximum then start to fall again. There are no significant meteor showers until the Lyrids, which peaks on the 22nd of April, so pre-dawn continues to be the best time for random meteor scatter contacts. (rsgb.org)