Propagation News – 19 April 2015

| April 17, 2015

The last week saw some very unsettled conditions in terms of geomagnetic disturbances, just as we predicted. The 14th, 15th and 16th were particularly bad, with the planetary K index hitting five and the solar wind speed exceeding 600 kilometres per second, sparking reports of visible aurora.

The solar flux index leapt up to 155 on the 16th, thanks to a number of sunspot groups appearing on the western limb of the sun. NOAA has the solar flux index forecast for next week in the range 115-135, but it could go higher than this. Continue to expect unsettled geomagnetic conditions with a strong risk of solar flares and associated coronal mass ejections.

On International Marconi Day, the 25th, your best bet to work the UK-based stations is probably 40 metres, 7MHz. If 7MHz doesn’t work for you, after dark, revert to 80m or 3.5MHz. There will be lots of Italian stations to work and 20 metres, 14MHz, will be the best band during the day. Look at 7MHz after sunset. To work the stations on the east coast of the USA and Newfoundland, again, 20m or 17m, which is 18MHz, are optimum.

VHF and up propagation news

The long run of high-pressure dominated weather is set to continue, although there are indications of a more unsettled theme at the end of the week.

The main area of high pressure will be focused near northern Scotland and this will mean the feed of air across the country, especially in the south, may be dry and less likely to produce good lifts despite the high pressure. However, there are indications that some moister air will flow around the top of the high at times, so it is definitely worth checking the VHF/UHF bands for enhanced conditions.

The Sporadic-E season is under way now and may provide openings on 10m and 6m on occasions during the week. Late morning and late afternoon are the best times to look.

For EME, throughout the coming week the sky temperature is relatively low, but with degradation rising as the moon moves away from the earth towards its apogee. The Moon will be highest in the sky on the afternoons of the 22nd and 23rd.

For meteor scatter enthusiasts the Lyrids meteor shower will peak on the night of 22 April, through to the morning of the 23rd. This is the first significant shower of the spring season.

Category: GB2RS Propagation News