venerdì 28 dicembre 2018

Propagation News – 23 December 2018

As this report has to take you up until Sunday, 6 January 2019 we can’t guarantee complete accuracy, but we’ll try to predict conditions for the Christmas period.
The solar flux index is pretty easy as it looks like it will remain at or near sunspot minimum-like conditions. The SFI will be in the range 69-72 with no real surprises. Geomagnetic conditions will in general be settled although NOAA predicts an elevated K-index due to coronal holes around the 29th and 30th, and again on the 3rd to the 6th.

We may expect some winter sporadic E, with reports of 10m short-skip openings to Europe being received already. Otherwise, this is the time for low-band openings, with the winter solstice giving us the long, dark nights that favour 160 and 80m propagation. Forty metres can also often throw up some choice DX, especially in the late afternoon.

We’ve just heard that OF9X is on from Finland again over Christmas, featuring three operators aged 18 or under. According to, 20 and 30m may be optimum for a contact during the day, moving to 80m at night.

And finally, a reminder that Santa Claus and his ham radio elves are on from Romania and are fielding the largest team of activators in all the districts of YO. All you have to do is contact at least three different YP-XMAS call signs and they will be able to issue an electronic award directly from Santa Claus. HF propagation to Romania is optimum on 20 metres during the day, but falls back at night. Forty metres, or more likely 80 metres will be the best bands for contacts after dark.

VHF and up:
It looks like tropo for Christmas, all because of a large high that will develop over the country from Christmas Eve onwards. This will bring a temperature inversion, which is good for tropo, and it will cover a large part of the UK and continent. The temperature inversion changes the refractive index of the air over a short vertical distance and leads to a duct forming that can cause signals to travel long distances with low degradation in signal strength. Unlike sporadic E, which is a rapid transient propagation mode, tropo is capable of providing long-lasting openings. So if Santa has brought you a new VHF/UHF radio for Christmas you could be in for a double treat with lots of activity to add those new squares into the log book.

The short but intense Quadrantids meteor shower peaks around 0200hrs on 4 January so you’ll need to be a night owl to hit the peak zenithal hourly rate of 80.

The Moon reaches maximum declination this Sunday and perigee on Monday so it is a good week for EME.

As a matter of interest, there is talk of a possible Sudden Stratospheric Warming event later this month when the winds in the stratosphere change dramatically over a day or so. This can lead to colder weather about two weeks later. Additionally, this change in the wind regime in the stratosphere may become part of an out-of-season pattern, which can favour winter sporadic E. It’s always worth a check over the Christmas and New Year period for short skip on 10m and 6m openings.