HF News
Last week was characterised by a falling solar flux index. Over the past week it has gone from 116 to 100, but the good news is that we have only had one M-class solar flare in that time and a multitude of lesser C-class flares that haven’t amounted to much.
As a result the Kp index remained low, certainly below four other than one excursion to 4.67 on the 12th.
This means propagation has been stable rather than outstanding. But as the winners of the WRTC last week showed, it was still possible to make 5,800 QSOs in 24 hours. An analysis shows that the best scoring band was 20m, closely followed by 15m and 40m. The predominant mode was CW.
Maximum Usable Frequencies over a 3,000km path have been topping out at around 19-23MHz at midday, according to the Dourbes DigiSonde.
Major DXpeditions to be worked this week include RT25AA (Arctic Legends IOTA DXpedition), TY5FR (Benin), VP5G (Turks & Caicos) and HP1/LA5IIA (Panama).
20m remains good for contacts across the Northern Hemisphere during daylight, while 15m offers better opportunities for north-south paths.
Next week NOAA predicts that the SFI may increase, perhaps up to 135. Geomagnetic conditions are forecast to be good for the first half of the week, but a Kp index of four is forecast for the 22nd and 23rd, so expect declining MUFs and poorer HF conditions around Wednesday and Thursday. There are currently no coronal holes to worry about.
Note that the RSGB’s IOTA contest takes place on July 25th and 26th.
VHF and up
The coming period of weather feels very much like what we’ve been getting in the last week or so. High pressure dominates the chart, and since it’s placed just west of Britain, this implies a north-westerly flow over the country, with a chance of Tropo for many areas.
Last week saw Northerly paths worked from UK up to OY, LA and SM on both 144 and 432MHz.
The high pressure part of the story suggests not much, if any, rain to speak of and therefore rain scatter is unlikely.
The auroral prospects are not especially great in radio terms. There are about three meteor showers currently giving a broad period of activity for meteor scatter operators and providing long-lived ionisation as fuel for sporadic-E.
In view of the links between Es and jet streams the upper air jet stream patterns suggest favouring paths to the southeast into the Balkans round to the northeast and Scandinavia for Sporadic E. Don’t ignore the options for multi-hop paths into the Far East in the morning on 6m and later in the day to the States, which have been very good lately.
For EME operators, Moon declination is falling again and we passed perigee on the 13th of July so Moon window lengths will shorten and path losses increase. 144 MHz sky noise is low, increasing to moderate next Thursday.