Propagation News – 8 March 2020

| March 6, 2020

The VP8PJ DXpedition to South Orkney Islands has now finished, with the last active day on 5 March. The DXpedition resulted in many UK stations putting South Orkney into their log, on all bands and modes from 160 to 15 metres, with a few reports even of 10m contacts.

This was a good example of how ionospheric propagation can be hard to predict as some of the paths looked very difficult if not impossible. But over a week-long period there were times when signals were able to get through, if only for short periods. It also showed how localised HF propagation can be, with some stations in the UK hearing them, while 100 miles away there was nothing.

Solar figures-wise, the week ended pretty much as it started with zero sunspots and a solar flux index of 69 to 70.

The week was mainly settled geomagnetically, apart from the night of Saturday, 29 February and Sunday, 1 March when the Kp index rose to four. This was due to a solar wind stream from a coronal hole on the Sun, which we predicted last week. Luckily, this was pretty short-lived and after it struck the Kp index fell back again to one or two, representing more settled geomagnetic conditions.

NOAA predicts that next week will be pretty similar to last with zero sunspots and a solar flux index around 70 to 71. The US Air Force predicts fairly quiet geomagnetic conditions with a Kp index around one or two.

At the time of writing, a small coronal hole has appeared on the Sun’s equator, which should become geoeffective this weekend. Another polar coronal hole is also growing towards the solar equator. This means that any solar matter from these holes could impact the Earth some time over the weekend or early next week. If it does, expect a possible short-lived pre-auroral enhancement followed by a general reduction in the MUF as the Kp index rises.

Don’t forget that next weekend is the Commonwealth Contest with CW HF stations on from Australia, New Zealand and Canada, as well as exotic locations such as Mauritius, the Cayman Islands, Belize and the Turks and Caicos Islands.

VHF and up

March is usually a month of typical spring gales and storms with the main Atlantic jet stream across the British Isles. Next week’s forecast is therefore not unexpected, and the main theme is a very changeable one with quite strong winds at times and periods of rain. No surprise then, that there is little prospect of high pressure and tropo for the VHF/UHF bands.

What’s left is a challenge for microwave operators to seek out some rain scatter from fast-moving scatter points in this train of lows and fronts crossing the country.

Also, if you have heavy local rain between you and the QO-100 satellite, look out for a reduction in signal strength from the transponders. This is due to the scattering effect of the water droplets causing blockage at the GHz band downlink frequency.

The strong jet stream will also produce some small opportunity for out-of-season sporadic E, probably towards the south into Spain or Italy.

Moon declination goes negative on Wednesday so the best peak Moon elevation will be in the early half of the week. Tuesday is perigee so, with path losses at their lowest, it’s still a good week for EME. 144MHz sky noise is low for the early part of the week but climbs slowly, reaching 750K a week today.

The small Gamma-Normids meteor shower peaks next Saturday, but with a zenithal hourly rate of just six, it’s nothing to get excited about, so keep looking for random meteor scatter QSOs around dawn.

Category: GB2RS Propagation News