Propagation News – 11 June 2023

Solar activity has remained at low levels over the past few days with only minor C-class and one M-class flare detected. The majority of these small flares were produced by active region 3327 in the southeast quadrant.

But a large number of sunspots means we are at a high risk of M-class or even higher flares over the next week.

HF conditions for last weekend’s Field Day were good and most teams put in good scores. Sporadic-E wasn’t too evident on HF, but there was plenty of F-layer DX to be had and luckily an anticipated geomagnetic storm never materialised.

The Kp index remained low for the whole weekend, apart from a brief excursion to Kp4 late on Sunday evening, which only lasted until the next three-hourly update.

Next week the Space Weather Prediction Centre thinks the solar flux index will be in the range of 140 to 155, with 155 coming much later in the week. We may expect some geomagnetic disturbance over this weekend, with the Kp index perhaps reaching four on Sunday 12 June.

Looking further ahead, the 18 to the 21 June is predicted to be unsettled with a maximum Kp index of five.

We really are into a period of summer HF propagation now, which is characterised by lower maximum useable frequencies during daylight hours, but higher MUFs during night-time.

According to Propquest, night-time MUFs over a 3,000km path are staying well above 14MHz and even 18MHz all night. You may even find DX on 21MHz up until midnight. So don’t write off the HF bands after dark as you may get some surprises.

VHF and up 

Sporadic-E produced some remarkable conditions early last week with 50MHz FT8 QSOs made with Australia during the day and afternoon, and evening openings to the Caribbean, Central, North and South America on FT8 and CW.

Caribbean signals were still being copied at 2200UTC on some days.

The 5 June produced QSOs for many on 70MHz including S01WS in Western Sahara. We are still in the peak Sporadic-E season, so it is well worth keeping a check on band activity via the various clusters or simply listening, particularly in the late afternoon.

The current weather setup is quite typical for this time of year and can be remarkably persistent. Although there have been suggestions of unsettled thundery weather arriving, it may be a brief visit and rather limited in extent. Some eastern areas stay close to the high pressure which becomes more dominant again throughout next week.

This means that Tropo will still be a component of the coming week’s propagation, especially along North Sea coasts, although this will tend to favour northern Britain as the week progresses.

The thundery weather could introduce rain scatter, especially to southern and western areas, and these storms should be easy to track in view of the light upper winds.

Recent solar conditions, as detailed in the previous section, continue to provide propagation variety with chances of aurora plus the usual mention of random meteor scatter.

Moon declination is still negative until Monday, and, as we are past perigee, we will have lengthening Moon windows and rising path losses. 144MHz sky noise is low all week.

Category: GB2RS Propagation News