Propagation News – 10 November 2019

| November 8, 2019

We had a more settled week, geomagnetically speaking. The Sun was a lot calmer, with a lack of coronal holes and fast solar wind to disrupt the ionosphere. We also had a sign again that Solar Cycle 25 is on its way. A tiny sunspot, numbered 2750 and belonging to Cycle 25, appeared in the Sun’s south-east quadrant. It didn’t last long before vanishing, but it is a sign that the minimum may be coming to an end. Another tiny spot also appeared, this time belonging to outgoing Cycle 24, but it too was short lived. Solar activity should remain at very low levels in the short term.

The solar flux index was in the range 69-71, but there was HF activity to be had if you searched hard enough. VP6R, on Pitcairn Island, D68CCC on Comoros and VK9NG on Norfolk Island were all active, and Guam, Oman, Mauritania, The Philippines and Japan were all spotted on 20m FT8. showed that the maximum useable frequency often exceeded 21MHz over a 3,000km path during daylight hours, often getting close to 24MHz.

Next week NOAA predicts the solar flux will continue to be around 67. Geomagnetic conditions are predicted to remain settled with a maximum Kp index of two. Quiet conditions should continue until 20 November, when a fast solar wind from a returning coronal hole should push the Kp index to a maximum of five.

VHF and up

It’s another unsettled look to the charts for the coming week, with a general low pressure feel to things. This means that rain scatter should be on the list for those on the GHz bands.

High pressure is very hard to pin down next week with a large high near the Azores, so according to the present charts tropo won’t be much in evidence. Sometimes these unsettled patterns can produce very rapid development of lows, and one such model run does indeed show the potential for a deep low over the country at the end of next week from Thursday night into Saturday. If this remains the plan as we get nearer, then it’s worth keeping up to date with the forecasts from midweek, especially regarding wind speed.

There are two meteor showers to look out for this week. The Northern Taurids on Sunday, then one of the major meteor showers of the year, the Leonids, peaking overnight from the 17th to the 18th. The Leonids is well known for producing meteor storms, the last one being in 2001. These storms are best seen when the parent object, comet 55P/Tempel-Tuttle, is near perihelion, its closest approach to the sun. Unfortunately it appears that the Earth will not encounter any dense clouds of debris until 2099 so don’t expect fireworks!

Visible peaks of around 15 meteors per hour can be expected and there will be much improved meteor scatter conditions.

Moon declination is increasing, reaching maximum a week on Sunday, so there’s plenty of EME time this week. The Moon is not long past apogee so losses will be high but falling. 144 MHz sky temperature reaches a peak of 500K on Friday.

Category: GB2RS Propagation News