RSGB
By RadCom Assistant Editor
March 27, 2026
After last weekend’s HF disruption, the latter half of the week was fairly settled.
Last weekend, the Kp index rose to 7, sparking visible aurora around the UK. The disruption continued, on and off, until Tuesday, 24 March, when the Kp index fell below 3 again.
The disruption was caused by a solar wind stream that had a Bz pointing south and reached speeds of more than 600km/second. The south-pointing Bz meant it was more easily coupled with the Earth’s magnetic field, hence the disruption.
Meanwhile, the solar flux index has picked up, rising from being in the 100s to hit 140 on Thursday, 26 March.
This, combined with a lower Kp index, has helped the ionosphere and we saw better maximum usable frequencies, or MUFs, over a 3,000km path later in the week.
But the threat of more geomagnetic disturbances has not gone away. Two large coronal holes are now Earth-facing and threaten to push the Kp index up once again.
NOAA predicts that the Kp index could rise to 4 on Monday, 30 March, and 5 on Friday and Saturday, 3-4 April.
The solar flux index is predicted to fall into the 130s and 120s again during the coming week, although this is still enough to provide good ionospheric propagation.
This may be your last chance to work the CY0S Sable Island DXpedition off the coast of Nova Scotia, which ends around Tuesday. 31 March.
Other DX stations to work this week include S21WD in Bangladesh, OX3LX in Greenland, CE0Y/DJ4EL on Easter Island, YJ1JXZ in Vanuatu, XX9W in Macao, T31TTT on Kanton Island and V4/SP9FIH from St. Kitts.
To recap, March and April are good months for North-South HF propagation, although we may see MUFs fall slightly with 10m band openings becoming rarer, at least until the Sporadic-E season starts in May.
VHF and up propagation news from G3YLA and G4BAO:
The current period of rather more changeable weather will continue to be the main weather pattern during the rest of the month.
However, with a large area of high pressure to the west of the UK, there will be times when the weather feels more settled and possibly with a hint of tropo briefly just before midweek.
For the rest of the time, active weather fronts will bring occasional bands of rain or showers with the possibility of some rain scatter for GHz operators.
Spring is always a good time to keep an eye on aurora since the geomagnetic disturbances are more likely around the equinox.
The Kp index, which describes the state of the Earth’s magnetic field, increases at times of potential aurora. So remember that once the Kp index gets above 5, it’s worth monitoring the bands for signs of fluttery or raspy signals.
Meteor scatter is still under the influence of random activity. As we head into April, we are getting closer to the next important meteor shower, the Lyrids, toward the end of the month.
Sporadic-E is currently in a dormant state so we are not expecting that to feature much in reports for another month. However, if you feel the need to check, use the comprehensive 10m beacons distributed around Europe to see the state of the upper HF bands for early signs of Sporadic-E propagation.
Last week was a busy one for EME with the Dubus 5.7GHz activity and the
CY0 and T7 DXpeditions are being worked by many.
Moon declination starts the weekend high, dropping to negative on Tuesday, while path losses continue to increase towards apogee on Tuesday, 7 April. 144MHz sky noise is low all week.
(Mike Terry, UK/BDXC)
