2 June 2025 Aurora

I am not sure how to define DX. Obviously it depends on the band in use. As a generalisation I might define it as stations I can contact which I would not usually be able to reach. This handy definition covers those situations where the activity is low as well as places where the propagation usually prevents a contact.

During the auroral opening from here on 2 June 2025 my understanding of this was a bit stretched. Some of the closer at hand stations I might have worked on a slightly raised tropo day. On or two I might have scraped through to on flat band conditions, but the result would have been scrappy. However, yesterday they were not just workable but they were all out loud on the loudspeaker. I might add, distorted and muffled on the loudspeaker --- but definitely loud.

There was plenty of early warning of this aurora.

Solarham warning of likely auroral activity on 1 June 2025

Despite the shockwave arriving on 1 June, the main effects of this strong solar event did not produce the desired result here until 2 June. I was listening on 1 June and it seemed as if I had missed the action, but the NOAA predictions showed activity extending over three days.

NOAA predictions for 1, 2 and 3 June 2025 made on 1 June 2025

It is quite possible for there to be a high K number at one stage but for the polarity to be moving north, in which case no enhanced conditions apply, and then for the polarity to head south and the band to open later. As it turned out, the magnetometers continued to see-saw during 2 June and conditions suddenly improved.

GM4PMK magnetometer on Mull, showing 2 June (top) and early 3 June (bottom)

I first tried 50 and 70MHz after around 11:00 without result. I could see people making contacts but there was not much happening here. I sometimes look at the FT8 waterfall while beaming at about 30 degrees, and if that shows dispersed traces something is happening. I could see MM5DWW on Orkney ranging in and out of auroral propagation on 50MHz. Sometimes I could copy him on FT8, other time his signal was wide and sounded auroral.

I could not raise anyone on either 50 or 70MHz. However, I had been watching DXMaps and I saw that various Russian stations were making contacts on 144MHz via aurora. Oddly they were posted as JT65 but the text said they were Q65c. They were also appearing on PSK reporter as Q65. So, more in hope than in expectation I went to the frequency they were listed as using (144.116MHz) and tried calling. No result. 

Due to the rotation of the Earth relative to the Sun, the effect of the aurora varies over time. This produces the "auroral oval" which is like a collar around the poles which varies in thickness. Usually the oval is thinnest in the mornings and as the Earth rotates the thicker sections appear to the north of me. In this case due to the high level of solar activity the ovals were predicted to be thicker than usual and therefore strong, but I still needed to wait for the widest portion to approach my part of the world.

Prediction for auroral oval for 1 and 2 June 2025

Note that these predictions made at around 05:00 show the aurora extending well down into the United States, while GM is at the back of the globe where a thin to non-existent thickness of aurora exists. In such situations there is nothing for it but to wait for the Earth to turn and bring a thicker part of the oval into my area of operations. This often happens in the early afternoon. Note also that the oval is very large, so this was clearly a major event.

It is often possible to wait of a thicker part of the oval to arrive, only to discover that the polarisation has gone against me by then. On 2 June, though, it went well.

I was listening on 144.116. This seemed an odd choice, but that was where the Russian activity was. Having said that I decoded nothing to start with. About to give up I heard something on the loudspeaker. Pursuing this, I had to turn the beam from my usual 30 degrees to 54 degrees before I found PD1BHZ calling CQ. After that contact I worked 16 stations on Q65-30C, all with the characteristic distorted auroral sound. These were 5 x PA, 4 x G, 4 x DL, and one each of EI, OZ and ON. Best DX was to Ronny DL1RNW in JO62, at 1039km. The event ended here at 17:15.

144MHz auroral contacts at GM4FVM on 2 June 2025 

Map made using  K2DSL mapping. As usual click images to enlarge if necessary.

Whilst none of this involved excessive distances, it was still very interesting. Most contacts were between east and south suggesting that the oval was indeed wide. Usually in smaller events the oval is further north and contacts tend to be more northerly. Also for the same reason the azimuth was further south than usual, between 40 and 54 degrees,whereas usually 30 degrees or less is what I find best. The benefit of reaching this area is that there are a lot more stations than to the north where I more often work.

DX, to me, is not solely determined by distance. These were stations I could not have expected to work so that is good enough for me. 

All in all an interesting opening. Although the predictions suggest the chance of another event today, I am not sure. It is that type of uncertainty which makes VHF DX-ing interesting. 

 73 Jim

 GM4FVM