RSGB
GB2RS News Team | October 9, 2025
We finally got rid of the high-speed solar wind stream, which caused havoc on the HF bands. But we are not out of the woods yet!
Last week saw the Kp index hit 6.67 on 2 October, and it was often up around 4 or more. Even though the Kp index eventually reduced, the ionosphere took its time to recover and things were not back to near normal until Tuesday 7 October.
Meanwhile, the solar flux index decreased to 131 by 8 October, so the HF bands were hardly humming by this time.
DX on the 10m band was hard to find. Openings to Europe were commonplace but longer paths were not so good, with only weak North American stations being heard later in the day.
A minor G1 geomagnetic storm watch was in effect for 48 hours from 7 October when at least one faint coronal mass ejection was predicted to pass the Earth. Only minor C-class solar flares occurred during the week, but that didn’t help too much.
CDXC members were reporting DX, such as V85T in Brunei on 15m and A52G in Bhutan on 20m – both using CW. However, there was not much to work on the higher bands. Southerly paths were a little better with 5X2I in Uganda reported on the 17m band using FT8.
Next week, NOAA predicts that the solar flux index will be in the range of 130 to 140, but it is also predicting geomagnetic disturbances today,
12 October. After that, the Sun may quieten a little with a maximum Kp index of 2 for the rest of the coming week before more geomagnetic disturbances. The Kp index is forecast to be 4 or 5 during the weekend of 18 and 19 October.
VHF and up:
The coming week is dominated by high pressure, either over the UK or near enough to influence the propagation and provide a prolonged period of Tropo weather.
It’s probably worth mentioning a few ground rules about Tropo operating.
Firstly, large areas of high pressure can produce widespread lift conditions due to the strength of the elevated temperature inversion 1 to 1.5km above the ground. The longer the high lasts, the lower this descends, so limiting maximum distance across the centre of the high.
Try beaming around the edge rather than across the centre. Secondly, there may be surface temperature inversions at night or in foggy weather, and these will provide temporary enhancements. Thirdly, the clue for a good ‘radio’ temperature inversion is the presence of fog or layers of cloud which give a better moisture contrast and ducting prospects.
One last point. Try other modes like SSB or CW rather than sticking to repeaters which can get very crowded in lift conditions.
There is no rain scatter in the frame this week and the Draconids meteor shower has just passed, so back to random activity on that front. On 8 October the Sporadic-E graphs at propquest.co.uk showed that there had been occasional spikes up to 5MHz or so. This may liven up the 10m band if we get any more. There have been a few weak auroral events but nothing too exciting.
For EME operators, the Moon’s declination is still increasing, reaching its peak today, 12 October, so long Moon windows and high peak elevation continue. Path losses are rising again after perigee on the 8 October.
144MHz Sky noise will be moderate to low for the coming week.
(Mike Terry, UK/BDXC)
