RSGB
RadCom Assistant Editor | April 24, 2026
Compiled by G0KYA, G3YLA and G4BAO on 23 April, 2026
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 4 and 5 at times with the result that maximum usable frequencies, or 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 10m but they were generally weak. Checks showed that paths opened up to Brazil, Kenya and Chile on the 10m band using 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, 16 April, no doubt aided by active sunspot group 4420.
Next week, NOAA forecasts that the solar flux index could rise to 125. It also predicts that the Kp index may remain low due to a lack of coronal hole activity. Fingers crossed that we don’t have any coronal mass ejections over the next week.
If this pans out as predicted, 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 usable, with very occasional openings on 24 and 28MHz.
DX to be worked this week includes TX9W from the Marquesas Islands; VP9KF in Bermuda; 7P8WR from Lesotho; C5B, C5C and C5D in The Gambia; D60DX in Comoros; and JD1BMH operating from Ogasawara.
VHF and up propagation news:
Compiled by G3YLA and G4BAO
The strong region of high pressure will remain with us for the next two weeks. So 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 beacons in Norway and Sweden into JO02 on 1.3GHz because of moisture present below the inversion.
However, 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.
As usual, watch for the Kp index going up to 5.
Keeping the best until last, we are approaching the period when Sporadic-E usually becomes a mode of interest.
Work is well underway on a rewrite of the Propquest website, which should be ready soon. This will be the go-to place for the daily updates during the 2026 Sporadic-E 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, which occurred on Friday, 17 April.
Apogee, the Moon’s furthest point from Earth and the point of highest path losses, occurs on Sunday, 17 May.
(Mike Terry/BDXC)
