HF News
Last week’s HF propagation was dominated by the effects of a high-speed stream from a large coronal hole on the Sun.
This pushed the Kp index up to four and five at times with the result that MUFs were lowered. The ionosphere struggled and often the MUF over a 3,000km path was below 21MHz.
Yes, there were some openings up to 10 metres, but they were generally weak. Checks showed that paths did open up to Brazil, Kenya and Chile on 10 metres FT8, but the signals were well down in the noise and barely workable.
Get used to this as it could be the norm for the next few years!
Meanwhile, the solar flux index increased to 116 by Thursday the 16th, no doubt aided by active sunspot group 4420.
Next week, NOAA forecasts that the SFI could rise to 125. It also predicts that the Kp index may remain low due a lack of coronal hole activity. Fingers crossed that we don’t have any CMEs over the next week. If this does pan out as predicted then we could have some decent HF conditions over the next seven days. Yes, the MUFs may be lower, but 14, 18 and perhaps 21MHz could be very usable, with very occasional openings on 24 and 28MHz.
DX to be worked this week includes TX9W Marquesas Islands, VP9KF Bermuda, 7P8WR Lesotho, C5B, C5C and C5D in The Gambia, D60DX Comoros and JD1BMH Ogasawara.
International Marconi Day is on Saturday the 25th, so a good opportunity to work places around the world associated with the inventor’s work. In the UK, look out for GB4LD (the Lizard), GB0IMD (Weston Super Mare) and GB2GM (Poldhu) among others. These may be workable on 40m from the UK as long as the critical frequency gets high enough. Paradoxically, the further you are away from the stations the better, due to be being outside the skip zone.
VHF and up
The strong region of high pressure will remain with us for the next two weeks or so and hence Tropo should be considered a first-choice mode for a while. The main criteria for the quality of any resulting Tropo is moisture. This is because moisture is a component in the calculation of the refractive index of the air.
High pressure usually produces dry air above any temperature inversion, but we may not always get the moisture below the inversion. The end of last week was good with reports of LA (Norway) and SM (Sweden) beacons into JO02 on 1.3GHz because of moisture present below the inversion, but if the dry easterly wind returns it may not go so well.
Meteor scatter should continue to be uplifted by the declining Lyrids meteor stream, which peaked last week, and rain scatter is off the menu since the charts are dominated by high pressure systems. Aurora is showing as occasional weak alerts, but apart from the odd fluttery signals on the LF bands, nothing too interesting at the moment, so as usual watch for the Kp index going up to Kp>5.
Keeping the best until last, we are approaching the period when sporadic-E usually becomes a mode of interest. Work is well under way on a rewrite of the Propquest website, which should be ready soon, and will be the go-to place for the daily updates during the 2026 Es season.
EME now and the Moon is moving into a lower noise position. Declination is high, but falling, and path losses will increase as we move away from the Moon’s perigee, its closest point to Earth, on April 17th. Apogee, the Moon’s furthest point from Earth and the point of highest path losses, occurs on May 17th.