Propagation News – 11 February 2024

A large sunspot region has been turning into an Earth-facing position and now looks like it could be threatening. Active region 3576 has already emitted a couple of low-class solar flares but could be poised for even more.

An M5.1 solar flare was detected around region 3575 on the 7 February as well. Updated imagery shows that an associated coronal mass ejection, or CME, was likely however, due to the location near the Sun’s south-west limb, it was directed mostly away from Earth.

The solar flux index remained high this week, hitting 190 on the 6 February before dropping to 188 on the 8 February. Geomagnetically, the Sun has been behaving itself with a maximum Kp index of only three on Sunday the 4 February.

But all eyes will be on active region 3576 next week as it could upset the apple cart.

Meanwhile, daylight maximum usable frequencies over a 3,000km path remain in excess of 28MHz, which is good for HF.

Next week, NOAA predicts that the solar flux index may decline to be in the range of 160 to 170. Geomagnetic conditions are also predicted to be settled with a low Kp index. Although, as we said earlier, that could all change if we have a violent solar flare and associated coronal mass ejection from region 3576 or any of the many other sunspots.

 VHF and up

Unsettled weather describes the pattern for the coming week, including some colder weather mixed in to provide snowfall for some areas, particularly in northern areas. This characteristic weather type will mean little chance of Tropo during the period.

Other propagation modes of interest might be even harder to find, unless you are thinking of rain scatter, which could be useful for a few suitably-equipped stations on the GHz bands. Other modes, such as meteor scatter or aurora, are also looking a bit thin. There is always the chance of some random activity, unlike Sporadic-E which is in its late winter lull that usually lasts until April for the 10 and 6m bands.

For EME operators, Moon declination is negative and rising, going positive on Monday 12 February. So there will be higher peak Moon elevations and longer Moon windows throughout the week. Path losses were at their lowest at perigee on Saturday 10 February.

144MHz Sky noise is moderate to low.

Category: GB2RS Propagation News