Propagation News – 15 November 2015

| November 13, 2015

We’ve had another week of disrupted HF conditions, thanks to an ongoing high-speed solar wind stream. The K-index hit six on the 10th and five on the 11th showing severe geomagnetic storming.

The maximum usable frequency over a 3,000km path has yo-yoed this week, being as low as 19.7MHz at noon on Tuesday, but hitting 33MHz on Wednesday. In other words, you had to keep a close eye on the bands as conditions changed quite quickly throughout the week.

Looking at next week, the 18 and 21MHz bands may provide good to excellent DX openings during daylight hours. The period from noon to late afternoon may be best, but both bands are likely to close soon after sunset and remain closed until some time after sunrise the following day, unless the solar flux is very high.

If the solar flux index remains higher than 100 or so, good DX may also be possible on 28MHz during daylight hours.

Next week, the solar flux index is predicted to be in the range 100-110, with continuing unsettled geomagnetic conditions, especially around the 17th according to NOAA.

VHF and up propagation news

We are in an unsettled weather pattern for the next week as Britain finds itself on the edge of areas of low pressure. The main centres of low pressure will be passing by to the north-west of the UK, which means that northern Britain will be quite windy at times. Even in the south, some stronger winds are possible as smaller lows track quickly east across southern England.

This points to poor VHF/UHF tropospheric conditions and the best prospect of DX will be on the 5.7 and 10GHz bands from rain scatter in any heavy showers. Remember that in the winter months, showers are more likely around the coasts.

For meteor scatter enthusiasts, next week brings the Leonids, the first of the three big winter showers. It has a short peak between 17 and 18 November. The Leonids has produced some of the greatest meteor storms in history. On the morning of 17 November 1966, visual meteor rates were as high as thousands per minute during a short 15 minute period, so be prepared for an intense but short shower.

For EME operators, the Moon is at the lowest declination at the moment so next week, moon windows will increase. The path loss will decrease as the Moon comes in to perigee—its closest point—a week tomorrow.

Category: GB2RS Propagation News