Propagation News – 4 October 2020

We had yet another week with zero sunspots and poor conditions. Matter from a solar coronal hole pushed the Kp index to six late on Sunday, the 27th, with corresponding detrimental effects on the ionosphere. The solar wind stream climbed to above 600km/s with the Bz component of the interplanetary magnetic field periodically pointing south. This meant that the solar wind could more easily couple with the Earth’s magnetic field, allowing matter to enter the ionosphere.

Maximum useable frequencies (MUFs) struggled to get past 14MHz on Monday while the geomagnetic storm continued. In fact, it took until Thursday for conditions to subside and even then the Kp index fluctuated between two and three.

But there was DX to be had, especially for paths that didn’t pass through the poles. Laurie, G3UML reported working Kamil, S79KW and Ravi, S79VU in the Seychelles on 20m SSB on Tuesday afternoon. And Carl, HS0ZOA in Thailand was also heard on 20m around the same time. This bodes well for HF over the coming month, which should see HF conditions improve thanks to a change in the ionospheric chemistry as we move from summer to autumn.

Next week NOAA predicts a solar flux index of 70, representing zero sunspots. There is always a chance that something could appear over the next seven days, but activity still remains quiet.

Geomagnetic conditions are predicted to be quiet, with very little coronal hole activity. A maximum Kp index of two is indicated, at least until Sunday, the 11th, when it could climb to three.
VHF and up:

We have another week of predominantly unsettled and, at times, wet and windy weather coming up, so tropo will be hard to find. The weekend offers a slow-moving area of low pressure over the country and although it eventually edges away to the east by midweek, it could give some very windy weather and certainly periods of heavy rain. So rain scatter on the GHz bands is the mode of choice once again.

A brief ridge of high pressure may transit the country on Wednesday and Thursday for a touch of tropo, but will soon be replaced by another slow-moving low over the country by the end of the week and a return of rain scatter conditions.

Time to fire up the EME kit again as we have positive Moon declination peaking on Friday giving long Moon visibility windows. Path losses are high and we are more than a week from perigee, but 144MHz sky temperatures are low to moderate all week.

October is a busy month for meteor scatter enthusiasts, with three meteor showers this week alone. The largest, the Draconids with a zenithal hourly rate (ZHR) of 10 on Thursday, the Southern Taurids with a ZHR of five on Saturday and the Delta Aurigids with a ZHR of two next Sunday. For more details of these showers, and other VHF related information, look at the excellent Make More Miles on VHF at mmmonvhf.de. (rsgb.org)