Wednesday, 12 February 2020

Sporadic E thanks to a kind sun.


Sporadic E on 11 February, who could have predicted that ???
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Before I start can I mention that the BBC's excellent "In Our Time" programme featured a talk on Solar Wind recently? The general idea of the programme is that a generalist egg-head who knows little about the specific topic (always played by Melvin Bragg) surrounds himself with three of the best academic experts on the subject, and they all try to tease out the detail for the audience in about 45 minutes. There is also a short round up at the end after the programme itself is finished..

You can find the podcast here:-
 https://www.bbc.co.uk/programmes/m000dg9n

Whilst it is not about radio propagation there is a lot of information in it. The science strand of these programmes can be quite interesting, especially for downloading to a phone and keeping for waiting for trains etc.

You can also find it on the BBC Sounds app.
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As many of you will know, I am very sceptical about the claims that we can predict Sporadic E using Jet Stream data. The Jet Stream, high speed winds high in the atmosphere may, I concede, play some part in the Sporadic E story. As for them being predictive - I just do not believe it. What evidence I have from here suggests that the predictions are just plain wrong.

For the past few weeks, the RSGB VHF predictions service (and the HF one too) have been predicting the likely path of Sporadic E openings using the Jet Stream predictions and they have been spectacularly inaccurate. No, wrong was the correct word for this. They just did not happen. This week they once again said that there would be lots of Jet Stream energy available, and I thought "so what?". This is interesting, but it does not help me with what day to be ready, where to point my antenna. Anyway, for the past few weeks, nothing has happened anyway.

Much more interesting for me was Solarham's prediction of disturbed geomagnetic conditions on 11 February.
3 day K-index prediction from NOAA as shown on Solarham
As usual, click to enlarge images if necessary.

Solarham (link on side bar) had been using the NOAA K-index predications to issue this warning a couple of days in advance, which meant I was ready.

A K number of 4 might suggest a weak aurora, but it was the prolonged spell of level of 3 during the day of the 11th which interested me.

It is time perhaps for me to return to stating my own theory about unusual Es events. Rather than pinning any credence on the Jet Stream I find that enhanced geomagnetic activity seems to fit in with most out of season Es events. I have a general vague term for this "enhanced geomagnetic activity short of an aurora" to describe when the K level rises. This gets me on aurora watch, but if the level never triggers a full aurora and I find myself listening to Sporadic E instead.

I have been banging on about this for years - here in 2017 ...

http://gm4fvm.blogspot.com/2017/12/using-aurora-warnings-to-predict-es-and.html

Thus the 11 February event looked like just the thing.

I had to go out twice during the day and so missed a lot of contacts. I also got so involved in 6m and even 4m activity that I missed a lot of QSOs on 10m, but here are the day's contacts again with labels this time:-
All contacts (28 to 70MHz) at GM4FVM on 11 February 2020

Over an operating period of 5 hours and 38 minutes I had 53 QSOs (all on FT8) into 12 DXCCs accounting for 38 squares. ODX was UW5ZO in square KO30, a distance of 1984km.

This is pretty much what I had expected. On many days of high Jet Stream energy, I look for Es and find nothing. When there is a day of enhanced geomagnetic activity I looks for Es and find a shed load. I am not saying that the Jet Stream has nothing to do with it, I am saying that Jet Stream predictions are no use in predicting what might happen, whereas solar activity often is.

Dealing with the bands, as usual with Es, action tends to start here on 10m and work upwards:-
10m (28MHz) contacts at GM4FVM on 11 February 2020
Early in the morning I was finding that the openings on 6m were very short and moving around geographically, so many failed to complete. I could get callsigns and reports, but not RRR so they failed in terms of duration being less than a minute long before moving somewhere else. On 10m they were long enough to complete. Later on in the day, when 6m and 4m became more stable I mostly sat and watched 10m as the activity rolled along. I could have made twice the number of contacts on 10m that I actually attempted, if my attention was not diverted elsewhere. It was on 10m that I worked my ODX for the day, to UW5ZO. This was early on - Es is best when the ionisation is weakest.

I devoted more attention to 6m, hoping to test out my recently installed antenna. Whilst signals were strong at times, up to +17dB, they tended to fade quickly, so more gain might extend the operating period long enough to complete the contact. So far so good. ODX was 9A2DI in JN95 (as it often is) at 1870km. I had 32 QSOs on 6m in just under 4 hours,  working 11 DXCC and 25 squares.
6m (50MHz) contacts at GM4FVM on 11 Feburary 2020
32 QSOs producing 25 squares shows how variable this opening was. Most of the time there were only two or three stations heard at once. As it moved around without much of a pattern, the stations changed location. Some of the French stations were there for a long time, as were some of the Balkan stations, whereas the Germans and Czechs stayed only briefly.

Only rarely do these events stray onto 4m. I think this is partly due to the low activity on that band, but also the trend for small pockets of territory to be covered as you get higher in frequency (which gets much more pronounced on 2m). Both these factors mean that your chances of picking out an active amateur are lower. However, I still did have some success:-
4m (70MHz) contacts at GM4FVM on 11 February 2020
Of course there are a lot fewer stations active on 70MHz. I was heard in Spain, which surprised me. I was pleased with that performance from the new antenna. 3 QSOs on 3 DXCC and 3 squares, of course. ODX was HA7WFN in JN97 at 1733km. Just to prove me wrong, he stayed on my waterfall for half an hour. Maybe the variation is not so much in which area is covered, but how wide the area of coverage. Perhaps as the area of ionisation varies this changes the stations we hear. So a station at the centre would stay on the propagation zone for longer than one at the edge. I have no firm evidence for this, I just wonder.

During Summer Es, the common type, sometimes you can just about see the effect of the Sun moving in relation to any point on the Earth (well, the Earth rotating really). The Es tends to move, as you might expect, East to West as the Sun does. People talk about "Es clouds drifting", but there are no Es clouds in that sense, and whatever you call them they don't drift anyway. The very way Es clouds work is that they are trapped layers of ionised particles, so by any definition they do not move much. During this event there was not much sign of any pattern. Probably the ionisation was popping up wherever the geomagnetic effect was strongest.

This was a good Es opening worthy of a Summer's day, when you might have expected it. That it happened in mid-February is interesting. It happened during a period of raised, but not very high, geomagnetic activity. Higher geomagnetic activity might have triggered an aurora and this posting would be different. Lower geomagnetic activity, well, that would just be another day when the weathermen would be spouting about Jet Streams, and nothing would have happened at all.

That is my theory, and I only have my blog to put it forward. Others, with the might of a national society and weekly prediction broadcast on amateur radio frequencies can put theirs forward in their way. Quite possibly we are both wrong. There could be 101 reasons why this event happened, but I know I could be wrong, I state it is just a theory, whereas others claim to have the answer.

Science moves on by rejecting old theories. It is bad science if you only look at events when they happen and ignore what is going on when they don't happen. It is bad science when you only look at what happens near you and not at what happens elsewhere. And it is bad science when you take your own speciality, however good you may be at it, and apply it's solutions to problems which have many and varied causes.

And finally...

As the Jet Stream theory enthusiasts are talking about a weather phenomenon in the North Atlantic, you would not expect to see Es activity enhanced in different parts of the world by such events.
Activity on 6m on 11 February 2020 on PSK reporter

It seems this event produced effects in the other parts of the world which use 6m, even during the night when VHF activity is usually very low. Is the Jet Stream around our UK shores responsible for all this?

73

Jim
GM4FVM

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