HF News
We had another mixed week of HF propagation, with a Kp index of six one day and then three days later a Kp of less than one.
The index hit 6.33 on the evening of May 4th, sparking aurora and poor HF conditions. But by May 6th it was back down to 0.67. So you can see why it is hard to predict what HF conditions are going to be like with ionospheric propagation being driven by the geomagnetic status rather than the solar flux index.
According to the CDXC Slack group, DX worked over the past week included TZ4AM (Mali) on 10m CW, T31TTT (Central Kiribati) on 12m and 15m FT8, XQ6CF (Chile) on 17m CW, VP8A (Falkland Islands) on 60m CW, 3B9G on 20m CW and TL8BNW (Central African Republic) on 40m SSB.
So there is DX about if you hunt for it. Interestingly, all the above, bar T31TTT, were on southward paths, perhaps reflecting poorer conditions on polar paths at times due to the elevated Kp index.
Next week, NOAA predicts that the SFI will remain around 115-130 with calm geomagnetic conditions for the first half of the week. However, unsettled geomagnetic conditions are forecast for May 15-18 with a possible Kp index of five.
With five sunspot groups visible on the Sun’s surface, and active region 4419, the source of two X-Flares on April 24, now about to turn back into Earth’s view, it is anyone’s guess what could happen next!
As we enter mid May we are getting closer to summer HF conditions. So Sporadic E on the higher HF bands, lower MUFs overall, but perhaps 14MHz staying open all night, are all features to watch out for. Look out too for 10m openings to Southern Africa around midday and paths to South America during early and late evening.
VHF and up
The current period of weather seems to be a mix of weak high pressure and low pressure systems vying for dominance. Therefore, it implies mix of radio conditions will share our attention, with weak Tropo from ridges of high pressure, but no big highs on the chart; and frontal rain- bands or heavy showers bringing a chance of rain scatter for the GHz operators.
The prospects for meteor scatter may remain elevated for a while since we have only just passed the peak of the Eta Aquarids on Wednesday May 6th, and remember the early morning hours tend to be best for meteor activity in general.
The aurora alerts have continued to provide a glimmer of hope, but mostly for weak enhancements, so look for a value of Kp=5 or greater and signs of ‘watery’ sounding signals on the HF bands before turning the VHF beams to the north.
As we move into the early part of the Sporadic-E season, it will become the mode of choice for us during the next few months. The general rule is to check for the two main periods of activity in mid-morning and again late afternoon/early evening. Listen for strong signals on 10m from Europe and then as the event develops the higher frequency bands will open up too. In a strong event 2m can even show up sounding like 20m, but early season events tend to favour 10m and 6m.
EME now, and the Moon is past minimum declination and increasing, giving lengthening Moon windows and increasing peak elevation. Path losses are decreasing now after apogee on May 4th. 144 MHz sky temperature is low all week until Saturday the 16th when the Sun and Moon are close in the sky.