Propagation News – 21 June 2020

| June 19, 2020

We had another week dominated by sporadic E HF contacts. Ten metres has been open daily to Europe and often until very late at night. There have been reports of USA and Japanese FT8 contacts from the UK during the day, continuing almost to midnight. By Thursday signal levels appeared to be dropping off at first but, by 1100UTC, Canada and the USA was rolling in via multi-hop sporadic E.

Many people have been heard saying that HF propagation is taking off and that the Sun has woken up again. The truth is that sporadic E is not due to sunspots, and as we head towards July and August we can expect the sporadic E openings to become less frequent. On this subject, the Sun has been very quiet with zero spots and an SFI of below 70. There has been an absence of coronal holes, other than at the Sun’s poles, which has helped keep the Kp index down to two and below.

F2 layer propagation is suffering from the summer doldrums, although there have been virtually daily reports of Jim, E51JD on South Cook Islands being worked on 20m SSB.

Daytime critical frequencies remain in the range of 4 to 5MHz, but are tending to be slightly higher just after sunset. This means that 20 metres may be remaining open to DX until nearly midnight local time. And it does suggest that 30 metres might remain open to DX all night. This is not unusual, as it is due to a change in ionospheric chemistry in the summer, with higher MUFs at night, but lower MUFs during the day compared with winter.

This weekend marks the Summer Solstice, traditionally a time when F2-layer DX is harder to come by. But with the sporadic E season well under way there is still plenty to keep HF enthusiasts happy.

VHF and up

As we said in the HF section, we are still firmly in the midst of the sporadic E season and the savvy operators will be keeping a constant watch for sporadic E, starting on 10m and working up to 2m as an event develops. To save spending a whole day on it, we would also suggest looking mid-morning and again late afternoon or early evening. In most years, openings can still occur into the first week of September, but from now onwards the openings become less frequent, hence the need to develop your own early warning routines to make sure none are missed. Check daily blogs to get some hints.

It is likely to be a mixed spell of weather throughout the coming week with elements of high pressure at times giving occasional tropo, especially across the North Sea and south across Biscay. Remember tropo paths are usually quite long-lasting, so there’s no need to rush like you do with sporadic E.

The other half of the mixed weather types involve heavy showers, sometimes thunderous with hail too. This is all good news for the microwave operators, giving a chance of some rain scatter propagation. The only way to work this on a day-by-day basis is to have some idea of where the showers are; there are many good online radar displays to help you with that.

Moon declination reaches maximum on Monday and is positive all week. Path losses are falling and 144MHz sky temperatures are low from tomorrow.

Continue looking for the best meteor scatter conditions around local dawn and take advantage of the continuing high activity levels due to many people still home working.

Category: GB2RS Propagation News