Propagation giveth ...

Propagation giveth and propagation taketh away. 

In the 21 days since my last posting here I have worked 220 stations. That is about 11 contacts per day.

That hardly describes what has been happening. I do not make 11 contacts every day, and it would be boring if I did.

Instead what happens is that there are hours of nothing happening followed by short spells of intense activity. The radios are on for most of the day while I come and go from the shack while building a Metcalfe cardboard kit. Each time I return I take massive punts on whether I need to be in there or not.

For most of the time the screens and maps are blank, or filled with "local" traffic. Some of this local traffic has to be of interest to me. Some of these people want to to work IO85, though it is not a rare square. To keep me active in these areas I try to keep my annual DXCC list ticking over. This involves me chasing countries in Europe and all over the world. Places like Guernsey and Wales can be as hard to work from here each year as some more exotic "once in a career" places.

So I keep active but there are still long very quiet gaps. 70MHz can be particularly quiet, but then it is only on 70MHz that I really see Sporadic E in action. 4m also keeps me on track to working 144MHz Es. Without 4m Es I would never be ready or pointing in the right direction for 2m Es. Having said that, I have missed all the 2m Es this season, though not for radio reasons.

I am not complaining about the quiet periods. I just want to make it clear that it is not a free-for-all at this time of year. I am happy - if I wanted 20m activity levels I would go on to 20m. No chance of that happening, is there?

For a lot of the time, DXMaps can look like this:-

70MHz DX Maps seen at GM4FVM with  no activity at 10:27 local time on 16 June 2023

Not much point clicking on this image to enlarge, but you can if you like.

It can be like that for long periods. 50MHz might show more activity, but often nothing reaching GM4FVM. It is amazing how small the DX searchlight can be, and how it seems to shine somewhere else.

Some things seems fairly certain. When dealing with a random feature, like where the DX stations are to be found, these factors seems pretty constant. The basic rules (excluding tropo) are:-

1) wherever DX is workable is now, it will not be soon

2) whatever happens this morning will not happen again the same way this afternoon

3) whatever happens today will not happen the same way tomorrow.

So whilst this means that if things are good now you cannot count on that later, at the same time if things are bad now they will be better later. The thing you don't know is how long "later" might be. That what creates the frustration fun.

The opportunities are generally divided into morning and afternoon sessions, and these are repeated tomorrow. So there are gaps overnight and around the middle of the day. At peak summer you get third evening session.

With tropo you tend to get a morning session and then later afternoon into evening and especially around and after sundown. Tropo openings can last for several days. This year tropo openings have been rare anyway. The much more stable pattern on tropo only goes to show how different Es, TEP and 50MHz F-layer propagation are by comparison.

With Es, TEP and 50MHz F-layer there is nothing you can watch for like a pressure chart as with tropo. you just have to take your chance. It opens unpredictably one minute and closes the next. There are websites promoting ideas like thunderstorms and "favourable jet streams" but these always look backwards after the event. They can predict nothing meaningful, only try to explain what you have already missed. At this point of scientific knowledge we are basically on our own with these propagation modes.

So here is what it has looked like here from one extreme to the other:-

a) Days when nothing much happened.

30 May radios on, me in the shack, no contacts at all

6 June radios on, me in the shack, also no contacts at all.

31 May one QSO - mind you it was a nice one to PY2XU on 6m.

7 June was not entirely without result. One contact all day - Jeff G8SEI on 2m. Thanks Jeff.

8 June had no 70MHz activity except D4L, a new DXCC.

11 June also just one contact - 4Z5LA on 6m. 

b) Days with sudden bursts of contest activity 

5 June had the 144MHz FT8 UKAC which produced 13 contacts into 5 DXCC in just 47 minutes.

12 June included the RSGB UKAC 432MHz FT8 contest - 15 stations in 61 minutes covering 4 DXCC.

c) Days with sudden bursts of activity on 50MHz

1 June - I worked seven in US and Canada on 6m in 21 minutes.

2 June - I worked 6 stations in Japan on 6m in 66 minutes plus a new country in the shape of 4L4LW.

15 June Two contacts all day and then a sudden opening produced 9 QSOs into USA in 38 minutes.

d) Days with sudden bursts of activity on 70MHz

29 May - 11 QSOs  which took 86 minutes to reach 5 DXCC and UN7MBH was good DX

3 June - 21 contacts in 10 DXCC in 80 frantic minutes.

Conclusions? No, more doubts.

There is a difference between quantity and quality. 8 June did not produce much activity, but it did provide D4L as a new one on 4m and J35X and J88IH for two new ones on 50MHz. Three new countries across two bands is worth waiting the whole day for. On the other hand, waiting all day when nothing happens is very frustrating. Is a burst of activity lasting an hour or so which produces no new DXCC better?

I don't know the answer to that, but I press on. When you see my charts with lots of contacts in various directions you might think that I am busy working DX all the time.

Nothing could be further from the truth. 

Three weeks work went into this one, even if the statistics ignore the start period and the end period when nothing was worked.

50MHz contacts over 2000km at GM4FVM 29 May to 17 June 2024

There may have been a lot of unproductive time but I reckon that it was worth it.

70MHz contacts at GM4FVM 29 May to 17 June 2024

70MHz has been pretty good really. I have noted several stations I did not hear last year, but who are familiar from earlier years. I think last year must have been pretty poor. So, a bit less silence than last year.

As for prospects for later this year --- who knows but my experience is that the two weeks after the solstice is better than the two weeks before. Let us see.

So far today I have worked ... nothing. Still it is only 14:43. You just never know and the 23cm UKAC this evening might be full of DX.

73 Jim

GM4FVM

Scientific explanations for how Sporadic E happens, and how amateur literature differs (long).

I have not been posting much lately. [What have you been doing Jim?] Well, at this time of year there is not much on the radio so I have been watching Ski Sunday. Isn't  Clément Noël amazing? Why is the Ski Sunday season so much shorter than the ski season?

And now Paris-Nice and the start of the cycling season. Very distracting. Remco Evenepoel, Cian Uijtdebroeks, and all those people.

I just wrote a VERY long piece quoting all the research papers about Sporadic E which I have also been reading. I have been reading research papers because most amateur books and websites say things about Es which are either just plain wrong or full of imaginings about thunderstorms, jet streams, upwards pointing plasma bursts and other fanciful tales.

Mike GM3PPE sent me a good scientific paper and then I turned up another one which together seem to explain the process. Further reading amongst amateur tales made me turn up a third one. So now, rather than using all that material in detail, I will try to set out what I understand. What I understood before was wrong. I can see that now.

I learn that the ionised layer does appear to come from material ionised during entry into the Earth's atmosphere. The E-layer ions last for a remarkably long time before recombining, thanks to being organised by the magnetic field and due their mass being greater than gaseous ions in other layers. The daily pattern of daytime Es during the Summer is driven by solar influenced wind shear. The Es layers descend towards the Earth on a twice-daily air current. There is a wealth of new information in these papers, plus some useful maps.

Here is one of my diagrams. It is an attempt to precis what comes later in the boring text.

Probable Sporadic Es process. Definitely not to scale. (GM4FVM after Arras)

This is a diagram you will need to click on to enlarge, if you want to see the detail. It covers a slice across the ionosphere between about 150km and 80km above ground. The magnetic field would run vertically into the page from above.

What follows replaces the VERY LONG piece with a LONG piece. Sorry, but it isn't easy to summarise.

I will put in the details of the papers at the end. Anything I have taken up wrongly in this piece is my fault.

For this purpose I will try to explain a timeline through the process.

Firstly the iron which will make up the metallic component of the E-layer arrives in the Earth's atmosphere. This is material from meteorites and similar bodies. Most comes from other parts of our solar system but a small amount may come from cosmic dust.

We amateurs are familiar with some of this stuff through meteor scatter propagation. However, many amateurs concentrate their activity on certain meteor showers during the year. These showers allow 5 or 6 days activity per annum. This tends to deflect attention from the fact that the majority of this material arrives at all other times, 365 days per year, 24 hours per day. These are the "random" meteors which hardly souls like GM4FVM and OZ1JXY used to make over 130 contacts entirely outside the meteor shower season.

There have been suggestions that if meteors are involved then the Es season should be influenced by the meteor shower timetable. This only affects Es to a limited extent. The showers produce only a short lived peak in the material arriving and anyway the peak period for arrival of meteors does not coincide with the shower season. Meteor showers are just the short but energetic ones we see and the vast majority are much smaller. In fact these small meteors, called micrometeors, are about the size of a grain of sand. 

Estimates vary but but overall about 25 million objects arrive on Earth each year weighing in total about 15,000,000 kg. The larger of these break up in to small grains. Amounts vary during the year, with a minimum in February and a maximum during Autumn. The amount and energy levels of the arriving particles varies during the day due to the orientation of the observer to the plane of the ecliptic as the Earth circles around the Sun. Amateurs can exploit these variations in meteor scatter propagation but none of it aligns with Es peaks.

These meteors arrive travelling at huge speeds relative to Earth. As they get closer the atmosphere becomes dense enough for friction and chemical action cause them to be heated to huge temperatures. Some are ionised. The ones we are interested in are made up of, or contain, metallic elements - principally iron. In addition to iron, some meteors contain smaller amounts of magnesium, sodium and calcium which also may become ionised. The density of the atmosphere is about right at around 100 to 150km above the Earth for meteors to be heated to the required temperatures. This region thus become a relatively dense layer of ions and we call it the E-layer.

We now have the iron ions (Fe+) and electrons in the right area. What you would expect from something as heavy as a metal is that it would fall to Earth. Even these tiny specks of matter will descend under gravity, though perhaps slowly as the density of the atmosphere increases. 

You would also expect that they would recombine with electrons to convert from Fe+ to Fe. We are familiar with the gaseous ions in the D- and F-layers recombining once the influence of the Sun is deminished at night or during the winter. However, in the E-layer they remain as ions and electrons for long periods. The Earth's magnetic field will exert an influence and tend to organise the two sets of + and - charges along the magnetic field lines. The Fe+ ions are a lot heavier than the gaseous plasma ions in the D- and F-layers and are therefore less likely to wizz around and find electrons. The combination of these processes give enough time for this mass of ioinised matter to come under further influences. The papers reckon it takes between 27 hours and 3 days for the Fe+ ions to recombine.

One of the surprising things to me about this is that the papers suggest that this ionisation takes place by the process of micrometeors arriving on Earth and not from the Sun's energy as in the other layers. I say suggest, as they do not mention solar energy at all as part of the ionisation process. I was wedded to the idea that ionisation in all three layers would be caused by the energy from the Sun. This would explain why Es occurs during the day and mostly during the summer. But apparently not. It matters little though, because the Sun still has a major effect as we shall see shortly. I cling to the idea that the Sun may play a part in keeping the energy level high enough for this story to continue.

The ionised material descends in a particular pattern. What is called "diurnal tides" result in a twice a day air current bringing the layer downwards at a specific rate. Amateurs report a twice a day peak in Es, presumably as the layer passes through the right region for propagation. Other patterns are superimposed on this, including daily- and trice-daily tides, so the picture is not simple.

Next thing in the story is "wind shear". As I understand it, wind shear is a type of turbulence created when a mass of air meets a more or less static object. As a callow youth I looked out the window of my lofty office in Dundonald House, a strangely curved multi-story edifice, and saw the snow falling upwards past the window. Everywhere else it did what you would expect, but here right beside the building it rose and swirled in eddys as if trying to polish the window glass. Not that the air is as dense in the E-layer as it was inside or outside the DHSS office in which I toiled.

The theory here is that the wind shear effect, when present, helps to shape and compress the metallic ion layer into a thin (about 1.3km thick) shaped mass of relatively dense molecules, atoms and electrons. Key to all this is that the wind shear effect is driven by the Sun - which makes Es a largely daytime and summer event. Crucial to it all is that at certain regions the mass of ions becomes sandwiched between eastwards (below) and westwards (above) winds. Although similar conditions occur in both hemispheres, the wind directions in the Southern Hemisphere are reversed in relation to the Northern Hemisphere.

So, many variables are coming into this. Although the quantity and mass of meteors is large it will vary to some extent, the ions are descending and will need to pass through the height we need them to be, they need to stay ionised long enough to create the layer, the diurnal tides need to draw them to the right place and the wind shear needs to be in the right aspect (the papers suggest generally eastwards winds in the Northern Hemisphere, and with an upwards component) to create the layer we need, and reversed winds above. It is surprising it happens at all.

None of this explains the effect we amateurs know as "Winter Es". This is not mentioned in any of the papers I have seen. It may be caused by one of the alternative Es mechanism which create other minor effects. Or it could be explained by the "spillover" theory. Possibly it could just be an aspect of the effect, mentioned in the papers, that Es tends to trail the annual seasonal cycle to some degree. Whatever the explanation, I think that it is important to keep in mind that I find Winter Es is responsible for about 1% of my activity and none of my DX whereas regular Es accounts for the other 99% of the activity and all of the interesting contacts.Winter Es is an odd quirk, but also a very small quirk.

How does the research method used differ from the methods we as amateur use?

The method used in the scientific papers was GPS Radio Occultation (GPS RO or just RO). This involves observing scintillations in GPS radio signals passing through the Es cloud. GPS satellites orbit at about 20200km. For this purpose the GPS signals are not received directly on Earth but are detected by low Earth orbiting (LEO) satellites which orbit at about 2000km above Earth.

Both transmitting (GPS) and receiving (LEO) satellites are outside the E-layer and are, in effect, watching the E-layer from "above" in relation to ground level. Actually they are on either side of the E-layer. As they travel at different speeds to maintain different orbits there are regular windows of about 5 minutes when the GPS signal can be scanned for the presence of an ionised E-layer between them. Any phase changes or multipath interference can be attributed to the E-layers This is not simple though, as other variables in other layers have to be eliminated from the results. However this appears to have been possible.

By using the RO method the researchers are able to observe the Sporadic E layers themselves. We as radio amateurs are only able to observe the results of Es in our log book. Beyond that we can use sites like DX Maps and PSK Reporter (PSKr) to look for patterns and interesting events.

PSKr works by receiving reports from amateurs over the internet and presenting them as lines on maps and other formats. It therefore shows only contacts made, not paths available. It mainly shows data contacts and rarely records beacon reception. Whilst some amateurs can click the box on their software to pass reports on to PSKr, not all do. Many amateurs use directional antennas which limit the possible paths. The results are therefore partial.

DX Maps and similar sites collect data from the DX Cluster and present it in the form of maps and various tables. This information is limited to anything reported to the Cluster, though it includes more reports of CW and SSB contacts plus selected reception reports. DX Cluster has a very helpful map showing the locator squares in which Es layers must be located plus the MUF at that point. This uses a mid point between the path between the reported two stations. This is useful but it a rough estimate, it is historic and it relies on reports - it does not plot the layers themselves.

I use both PSKr and DX Maps extensively. They help me chase DX, but they do not give any clue as to how the E-layer is made up, nor any predictions about how or when the propagation might appear next.

In my view the methods used by amateurs tends to give a distorted view of Es, as of course we rely on other stations being around to receive our transmissions - and for example there are not many in Africa and vanishingly few in the middle of the Atlantic Ocean. The Es map in DXMaps then estimates that the refraction happens mid-way between the stations and shows this as one locator square. This is very helpful but not really scientific.

How does the scientific literature differ from what we read in amateur literature?

The scientific view is that the presence of Fe+ ions and wind shear are the crucial factors in forming a dense thin layer which makes Sporadic E propagation possible. Solar driven winds in the E-layer and the effects of the Earth's magnetic field are also crucial.

Reputable amateur publications give details of the scientific data but steer clear of going further.

Other amateurs have often taken the results from DX Maps, PSKr and other sites and laid them onto weather maps. From this they have come up with the idea that somehow weather systems close to ground play a part in Es formation. As there seems to be no direct relationship between our weather and conditions 100km or so up in the atmosphere they often postulate all sorts of mechanisms without any scientific basis. They then publish this on the Internet as is their right, just as I am doing now. Sometimes their ideas appear in books, society publications and magazines.

The amateur approach creates huge variables because of the indirect and variable nature of the data collection. This is in addition to their often cranky ideas about the influence of Earth weather on the upper atmosphere.

Many amateurs have looked for "triggers" for Es. Unlike the scientists they cannot see the E-layer except where it creates reported propagation for amateurs. I doubt very much if there is a "trigger" involved. The ham literature I have read says that the authors are looking for something they think needs to cause the ionisation in some direction or at a certain time. The scientific papers say that tons of ionised particles arrive every day without any other input and variables in the ionsphere explain the variability. If ionisation is already present, why look for a trigger?

One particular internet piece written by an amateur seems to go right off the path beaten by the scientists. He claims that tools like DX Maps and PSKr give amateurs a reliable way of spotting and tracking Es formation. In my view they only provide a method of tracking the contacts. He reckons that storms and lightning from Earth weather trigger Es. Having looked at the scientific evidence I feel that he is mistaken. All that DX Maps and PSK reporter do is to record some of the outcome of Es filtered through a skewed fabric of random influences.

PSKr often shows just single receptions due to transient effects which are not Es related. DX Maps also shows contacts after they have happened, and only the ones reported to the DX cluster. They cannot show paths which are not reported for all sorts of reasons. They never show potential paths which have not been exploited nor ones that don't exist. Only scientific approaches which, like the ones summarised here, can actually image the existence or not of Sporadic E layers and their location. This is the best way to try to find an explanation for what is happening. This research can show the process involved in creating the propagation in real time as scanned by the satellites.

When well meaning amateurs take charts from PSK Reporter or DX Maps and use them to try to plot Es activity it is almost inevitable that they are using unreliable data. When they go further and try to align this with weather, storm or lightning maps, they are likely to find doubtful patterns. If they go further again and try to predict future Es based on already unreliable information then the outcome is likely to be pretty wide of the mark.

Finally.

Right. Where have we got after all this waffle? There is plenty of scientific evidence as to what causes Es. We as amateurs can use the excellent tools available to us (including PSKr and DXMaps) to exploit this and have lots of interesting fun. By understanding the process by which Es is formed we can develop our learning. As for trying to out-think the professionals - you can try but you might be wasting your time. 

A basic human freedom is that everybody is authorised to waste their time as they think fit. Even me.

Sources.

These are the working links as I write this. Contact me if they do not work and I will try to help if I can.

1) A Global Survey of Sporadic E Layers based on GPS Radio Occultations by CHAMP, GRACE
and FORMOSAT–3 / COSMIC. Christina Arras. 2010 GroForschungsZentrum Helmholtz-Zentrum Postdam. Scientific Technical Report STR10/09

https://gfzpublic.gfz-potsdam.de/pubman/faces/ViewItemOverviewPage.jsp?itemId=item_23022

You can download the entire paper by clicking "full text".

This is a very full (~100 pages) paper, one of the first using the RO method. There is some very good information on how RO works.

2) Examining the Wind Shear Theory of Sporadic E With ICON/MIGHTI Winds and COSMIC-2 Radio Occultation Data. Y. Yamazaki. 2011 Geophysical Research Letters Vol 49 Issue 1.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2021GL096202

 As the wind shear theory was not well proven at this stage this paper concentrated on that matter. These are some interesting maps and diagrams.

3) Morphology of sporadic E layer retrieved from COSMIC GPS radio occultation measurements: Wind
shear theory examination. Y H Chu et al. 2014 Journal of Geophysical Research: Space Physics. Research Article 10.1001/2013JA019437.

https://pdfs.semanticscholar.org › c9a0 › 3c2ab977b9507b019e661904c5a4ebdf6fa2.pdf

A further verification of the wind shear theory. This paper includes many more E-layer maps and diagrams which will be of interest to the amateur.

Senegal on 6m. Not trans equatorial, but still TEP?

 I have been away again. This time to Poitiers in France

GM4FVM in the cafe in the Blossac gardens in Poitiers France (photo Mrs FVM).

This photo does look a bit like one earlier this year in Vught in the Netherlands, though with a different Belgian tipple. Anyway, no radio on this trip. I note that once again, on my second visit to Montparnasse station in Paris, I was stopped and asked for a ticket by an RATP official. I am not sure if it is because of the way I look. Maybe they had intelligence that I might be a ticket dodger. Still, I suppose two visits separated by 35 years is a small sample. I must watch out for this again, as the Metro journey from Gare du Nord to Montparnasse is never easy at the best of times.

What follows has been revised on 12 October 2023 to include updated diagrams. It has been developed into a fuller article and this should appear on this blog later.

Back in Scotland now, on 28 September I worked Elivra, 6W/IV3FSG, in Senegal on 6m.

50MHz contacts at GM4FVM on 28 September 2023

As usual, click the image to enlarge if necessary.

This contact reminds me of the one with TT8SN in Chad on 20 October 2022. This distances are similar - TT8SN is 5084km, while 6W/IV3FSG is 4766. Both are at the southern extreme on the Sahara desert. Both were happening at around the time of Trans Equatorial Propagation (TEP) further south into Africa. That posting can be found here.

At the time I pointed out that the propagation mode behind this contact to Chad was a mystery. Now after another one I feel a bit more certain as to how it happens.

In this recent case just before I worked 6W/IV3FSG I worked EA2AR and F5TMJ (LA3EQ had been worked 10 hours earlier). So there was Sporadic E towards the south of me. Later I heard V51WW in Namibia which was clearly TEP as he is on the other side of the Equator. I heard GM6NX working ZS6NK, so that is further evidence of crossing the Equator by TEP. Also, I could hear Spanish stations working V51JH and V51CO in Namibia. I was also hearing station in the same area when I worked TT8SN last year.

So that seems to sew it all up. There was Es from here to Spain, there was TEP from Spain across the equator to Africa, and presumably Es linking to TEP from Scotland to Africa. Es linking to TEP. Problem solved. That must be how I worked Senegal.

Erm... there is a flaw in this logic. Senegal is not across the Equator from Scotland. It is 14 degrees north of the Equator. Ah but, you say, that is the Geographic Equator. For this purpose we have to consider the Geomagnetic Equator, which is diverted north across Africa. True, but the diversion is not enough to put the Geomag Equator north of Senegal. From what I can see it passes just south of Senegal.

One of the many representations of the Geomag Equator on the internet

None of these images on the internet are too clear. But I conclude that the Geomag Equator passes just south of Senegal, maybe about 12 degrees north of the Geographic Equator.

So if the signal from 6W/IV3FSG was an example of  TEP propagation, it did not cross either of the Equators. There seems to be something in the expression "Trans Equatorial" which suggests to me a crossing of the Equator.

OK, having read various articles, especially those written by James Kennedy K6MIO/KH6, I think I have now got some sort of a grasp of this. Based on his ideas I have created a diagram showing the process.

Generalised representation of classic TEP (after K6MIO/KH6)

This shows the "classic" impression of TEP. Ionisation well up along the Geomag Equator and rises up into the F-layer, forming two "anomalies" or "electron pools" as K6MIO/KH6 describes them. The signal path rises from one side of the Equator, gets deflected twice at the anomalies, and reaches the receiving station on the other side of the Equator (and then presumably extending by Es to reach me). Great for V51WW in Namibia, but not so good at explaining hearing 6W/IV3FSG from Senegal.

However, K6MIO/KH6 does have an explanation of observed propagation effects which does explain both stations being on the same side of the Equator. In this case, I reckon "Trans Equatorial" refers to the effect in the ionosphere as shown by VK4YEH. This type of TEP is decidedly one sided.

K6MIO/KH6 describes the one sided effect as "Single-Lane F2" propagation. In his articles he shows diagrams of many TEP paths which are entirely in the north "Lane" reaching only north of the Geomag Equator. The paths he shows are mostly across the Pacific and several run generally south east to north west, but he also shows one running north east to south west . However, in the text he suggests that they can run north-south. The path to Senegal from me runs north east to south west at azimuth of 201 degrees.

James also says that the two stations must be within about 2000km of the same ionisation peak and if north-south they must be on opposite sides of the lane. Now I have done a little back of the envelope investigation of these figures in relation to my QSO. If indeed Senegal is close to the Geomag Equator (which the internet maps suggests it is) then it is far on the opposite side of the lane from Europe. James' article suggests that the skip points will be between 10 and 20 degrees from the Geomag Equator.

OK, assuming that TEP got the signal to Spain and Es carried it the rest of the way, my calculations suggest that the Senegal-Spain section would be about 3000km and the Spain-Scotland section would be about 1700km. These are both well within the potential of the two propagation modes. All the other conditions in the K6MIO/KH6 paper seems to be met. This looks like "Single-Lane F2" as described in the TEP articles.

K6MIO/KH6 has done proper scientific research and analysis, I have just read his articles. I am no earth scientist. I have used his ideas as the basis for a diagram which I think represents the situation on 28 September when I worked Elvira in Senegal.

50MHz situation on 28 September 2023

I come to the conclusion that Single-Lane F2 is the method of propagation behind both of these contacts - partly by being convinced by K6MIO/KH6's scientific rigour - and partly by ruling out the alternative explanations.

Multi-hop Es looks very unlikely. I hate to write "never", but I cannot think of me ever seeing multi-hop Es at this time of year. Sure, there is Es all year, but outside the peak season (in my experience) it is single hop only. It would need to be three hops for this contact, two would not be enough. Add to that the time which was 19:30 local, and then multi-hop Es at this time of year seems extremely explanation. In July, maybe, but not in late September. Unless of course there is new type of multi-hop Es ....

Ordinary F-layer? I am pretty sure that the southern African stations were TEP and not F-layer propagation. There are  a few signs of what might have been classic F-layer propagation but not enough to convince me that it has happened yet. Of course, TEP is F-layer propagation, but a very different type.

No, given that there was classic TEP and single-hop Es at the same time as this QSO this definitely looks like Es linking to "non-Trans-Equatorial-TEP" or to give it a better name "Single-Lane F2 associated with TEP".

I could say a lot more about Es linking and the distances involved in single-lane TEP, but I will not do it here. Let me just leave this as an idea. The idea is that when there is classic TEP around linking me in Scotland with the far south of Africa, there also seems to be [something] linking me with much further north in Africa. These shorter paths do not cross the equators. I believe that the [something] is single-lane TEP. In believing this I have thought about classic F-layer and multi-hop sporadic E propagation and rejected both as likely candidates.

OK, maybe [something] is another entirely new propagation method which just happens to occur when I hear other TEP. I doubt it.

Just because the path of a contact does not cross the equator does not mean we can rule out that it is caused by a trans-equatorial effect, such as TEP. 

I see this type of propagation posted as TEP. The correct name in the articles is "Single-Lane F2" but as it is associated with TEP I doubt if anybody is going to change their idea of what to call it. So I will continue to post it as TEP for now as it is not classic F2 propagation either. Put another way, I do not believe that these contacts would have happened but for the TEP event which was noted at the same time. 

Bit of a description dilemma there for now.

73 Jim

GM4FVM

Be thankful for what you got

Can it be almost 50 years since I was first licensed? I sat my Radio Amateur Examination in 1974.

Ah, 1974. Simpler times. My revision notes consisted of one book someone gave me when I bought a receiver. And that was before they invented propagation, so no need to learn about that. But more on the days before propagation in a later post. Perhaps.

1974 had a warm Summer and "Be Thankful For What You Got" by William DeVaughn. What a great record for a hot Summer. Long and slow, with an insistent bass line and tight percussion. They don't make them like that any more.

"Keepin' up with Mr Jones? You don't need a loan!"

Despite William's advice I was later to borrow the money to buy an FT-101. Not exactly keeping up with Mr Jones, I told myself, just trying to hear and be heard.

Deary me. I still just want to hear and be heard. Yet, I get flustered when my station does not seem to be performing. I seem to have forgotten Billy's mantra about not to pushing on. I should be more thankful for what I have.

I also get frustrated about propagation which seems to have become "a thing" in the intervening five decades.

And so I was complaining about 6m propagation on this blog as recently as 9 days ago here

"That gap into North America looks very glaring"

but I also said 

"I have in the past worked in that direction into mid-August. There is still a chance."

Does complaining work?

Next day there was an opening and I worked 18 stations in the US and Canada over the space of 50 minutes starting at 13:09. I then had to wait four days until the next opening at 12:10 when in 26 minutes I worked 22 stations across the Atlantic. And two days after that I found the band open at 21:07 when I worked 9 stations in 23 minutes, and the activity only stopped when I realised that I was falling asleep.

US and Canadian stations worked on 50MHz at GM4FVM from 24 to 30 July 2023.

Total opening time was 99 minutes for 49 stations, which on FT8 means being pretty busy. All three openings met my standard for a pile-up, in other words I was not calling CQ but people were calling me and a queue formed to work me.

Perhaps I should complain less and be thankful for what I have got.

I heard somewhere that patience is a virtue. Maybe I should become more virtuous. 

Not so sure about that one. 

"Be Thankful For What You Got" sleeve. Image: Wikemedia Commons

73 

Jim GM4FVM

Ionoscatter opening on 144MHz?

I am not very familiar with ionoscatter propagation. My knowledge has been limited to 

a) it is a forward scatter mode from the D layer

b) it peaks with D layer ionisation, so high summer at mid-day is a good time

c) it does not depend on atmospheric pressure like tropo

d) distances achievable are around 900 to 2000km

e) best frequencies are 30 to 60MHz, though up to 100MHz is sometimes quoted

f) it needs a lot of effective radiated power to work

The interplay between (e) and (f) tends to rule it out for me. At 50MHz I have 200W at the antenna, and on 70MHz it is 50-100W. On the other hand, at 144MHz I can put 200W to the antenna which has a lot more gain than is available on the lower bands. My ERP on 2m is twice what I have on 6m, even with the same power at the antenna.

So the only band I put out a reasonable ERP is above the ideal frequency for working Ionoscatter. I have read about it but I did not think it was for me. So, basically, I have ignored Ionoscatter so far.

As you may gather from this post, this period of overlooking Ionoscatter is now over. Yesterday was 20 June, almost at the Summer Solstice when the day length was 17 hours and 35 minutes here. Not a bad date for Ionoscatter. Mid Summer, mid day, a handy time to be looking for this.

There is an interesting article here  

https://www.qsl.net/oz1rh/ionoscatter/ionoscatter_lecture_2002.htm#_Toc10594132

The first sign I had that something odd was happening was hearing DK1FG working a local station. Now Gerhard is an EME operator with an antenna array with 10dB more gain than mine.  Also he has an linear amplifier with about 6 or 7 dB more than mine so his ERP will be tens of kilowatts more than mine, and probably a lot more. With the benefits of his much taller mast he will have several more dB over me there too, plus he has a superb site. With the advantage of antenna elevation he can also set his antennas to the optimum angle for ionoscatter. Despite all of this, I normally cannot hear him because under normal conditions no path exists. Hearing him yesterday was something of a surprise, working him was a greater surprise.

These were not "normal conditions". The distance between DK1FG and GM4FVM is 1128km, an ideal distance for ionoscatter. To achieve a contact like this we are exploiting one of ionoscatter's key characteristics. Whilst there is a ideal frequency range of 30 to 100MHz, this is not a strict limit. In fact as you exceed those values the losses rise but the propagation continues to work with more path loss until you reach the noise level. So by using an EME capable station at one end of the QSO it becomes possible to generate the sort of power budget which would make ionoscatter possible at 144MHz. Much lower ERP should work at 70 or 50MHz.

DK1FG's mast and antennas (DK1FG's QRZ.com site)

I do not have that sort of station but the path loss arithmetic suggests that a more modest station at one end of the QSO should be able to make ionoscatter work at 2m. From my point of view I decided to treat ionoscatter like moonbounce - I could not work a station like mine at 1000km range, but I might be able to work a superstation.

Actually using ionoscatter on 144MHz proved a bit tricky. Stations were on great circle bearings (unlike meteor scatter or aurora) but signals were patchy with what looked like steep QSB. It took a while to get a complete QSO. In line with the idea that around mid day would be best, I worked DK1FG at 11:55 and then worked four stations up to 14:22. I also failed to complete with one station and worked another one which may have been tropo.

144MHz contacts at GM4FVM on 20 June 2023

I have put 100km circles on this map to show what happened next. The following QSO was with F5RZC. Jean-Francois also runs a powerful station but he is "only" 642km away and I can work him under slightly raised tropo conditions. I am pretty sure that this was a tropo contact, and although not very strong, it did not show the peaky QSB shown by the other contacts.

After that I worked SM5DIC (JO89 1197km), OH6KTL (KP02 1506), SM1HOW (JO97 1270) and SM0DJW (JO88 1240). I failed to complete with OH2FNR (KP20 1641). These are all good VHF stations with better antennas, receive pre-amps and power levels than I have.

So why am I rambling on about how much better stations these are? Because that is what is needed for ionoscatter. It would not be required for a tropo contact during a tropo lift at these distances. All the signs are there for ionoscatter, and this is reinforced by the operators sending postings to the cluster indicating that this was ionoscatter. 

I suspect that the contact with F5RZC was tropo. There was no other tropo around and it did stand out as unusual. However, it appears to be too close for ionoscatter. The others look more certain.

Could I do this again? Can I use it on 6m and 4m where is might be more effective outside the mid-Summer mid-day window?

P.S. During similar conditions today I caught this screen grab which shows the distinctive patterns on the waterfall. Tropo would have shown long slow QSB and strong signals, this shows patchy weak signals.

Set against this, I seem to have forgotten several days of nice tropo since the last posting. The high pressure collapsed, the tropo went away and that is why I noticed the ionoscatter.

73 Jim

GM4FVM

Sporadic E and geomagnetic storming.

This is what Solarham (see sidebar for a link) stated:-

"Geomagnetic Field and Aurora - Past 24 hours : Storm."

This suggests to me that an aurora is possible though there was no enhanced propagation of that type noted at GM4FVM. There were however some auroral contacts by stations to the east of me.

This is what I have termed in the past a "geomagnetic disturbance short of an aurora". And frankly these are the ones I am really interested in.

What there was turned out to be a lot of Sporadic E propagation.

Once again this posting is about the close correlation between disturbed solar conditions and enhanced Sporadic E events. I say "once again" as that was the theme behind eleven postings on this site dating back to 2015. You cannot say I have not been banging the drum about the fact that I use sites like Solarham, NOAA and NASA to predict likely Es openings, and then I switch to the magnetometers of the Norwegian stack, GM4PMK and STEREO to monitor the events as they unfold (links in sidebar). 

One of these postings, in 2017, was titled "Using aurora warnings to predict Es". I think it is clear what I am doing. Meanwhile my national society the RSGB continues to bleat on about Jet Streams and make predictions based on terrestrial weather which simply miss entire events.

Therefore you may already have noted that for years and years I have been pointing out that Es is often to found when there is geomagnetic disturbance. You may already be bored by this. Still, here I go again with an even bigger and more conspicuous set of events.

During the peak Es season, say in June, it is not easy for me to see the link because there is just too much Es around which may hide the opening. On the other hand during the least Es activity, say during February, increased activity on the Sun may not open a band which is firmly closed. 

As radio amateurs what we are hoping for at other times is for enough energy to be imparted to "push the ionosphere into producing a Sporadic E opening". My words.

I often see these openings most clearly during the shoulders of the season. April and early May plus late August and September. That is when I believe that geomagnetic storms show that they can produce unexpected Es. At other times it is no so clear but I have posted occasions when I noted that it happened.

There was no Es worked here between 11 August and 17 August. No Sporadic E here at all for a week. The Es season seemed well and truly over.

Then on 18 August a geomagnetic storm reached us, which in my book indicates that Es may be just around the corner. Solarham had issued a warning well in advance.

It is difficult to work out which day the results of the coronal mass ejection might arrive and a second event warning was issued the following day - actually a multi-event warning.

So there were in fact several events on the sun which sent mass ejections earthwards. They generally pass first with a shockwave and then later with a geomagnetic storm which I believe set off the Sporadic E events.

The following image from the GM4PMK magnetometer show the first storm followed by the second shockwave.

GM4PMK magnetometer readings for 18 August 2022

What I would have expected during a period when the planetary index reached K5 as seen here would be an Es event. And here it is as seen at GM4FVM:-

50MHz contacts at GM4FVM on 18 August 2022

My first contact was at 13:09 but it really started to hot up at 19:05 and continued to 20:23. 9H1TX was a new DXCC on 50MHz and a new square for me. After the shockwave I decided to pack it in as that seemed to have ended the event, but I expected things to carry on the next day, which turned out to be the case.

I started on the 19th at 06:00 and the contacts continued until 09:47.

Here is the map of contacts on 6m for both days:-

50MHz contacts at GM4FVM on 18 and 19 August 2022

So in a period less than 24 hours I worked 43 stations on 6m, in 36 squares and 14DXCC. ODX was SV3AUW in KM17 at 2770km.

The PMK magnetometer did not show much effect on 19th but the ionisation from the previous day seemed to continue. Perhaps one of the clearest signals of what what happening was given by Solarham which showed the planetary index at K5 coinciding with the times of the opening.

Solarham storm warning and K index on 17 to 19 August.

It seems to me that Sporadic E openings like this are more likely to be related to geomagnetic storm conditions than purely to the K number. Of course those two are closely related but from what I have observed disturbed conditions seem more likely to produce Es than even strong but steady streams heading from the Sun. The proton and X-ray recordings also seem very reliable indicators of useful events on the horizon, as shown in previous postings.

So what causes Sporadic E?

Nobody really knows.

The ARRL handbook refers to possible metallic particles in the E layer and to wind shear. It seems likely to me that the particles become ionised under the influence of solar streams and form a layer located by the Earth's magnetic field. Once suspended it seems inevitable that movements in the atmosphere below the fixed layer (wind shear) will organise and enhance the layer. That is what I make of the ARRL handbook's explanation and it seems to make sense to me.

Reference to metallic particles is sometimes linked in the literature to these molecules having their origin in meteors. This theory does not relate to the ionisation created when we amateurs use scatter propagation during meteor showers. There appears to be no link between meteor showers and Sporadic E. The particles possibly implicated in Es are likely to be from the random accretion of material by the Earth which becomes ionised and formed into the E layer by the processes set in train by the geomagnetic disturbance. That is if meteoric material is involved at all - this seems to be speculation (like so much about Es).

During the peak Summer season there is enough ionisation in the ordinary course of events produced by UV and other radiation for openings to occur regularly. I see a pattern that during the Autumn and Spring geomagnetic disturbances can produce enough additional ionisation to cause periodic openings when otherwise things are quiet.

And as predicted on Solarham  on 17 August, the arrival of several solar steams over a number of days was likely to produce several openings as this table shows:-

Solarham forecast for 3 days plus results for previous days.

The pattern of raised K number shows a close correlation with my log book. Es occurred when the K level rose to 4 or 5.

I cannot continue to report on the events of these repeated disturbances so I will summarise the four days up to the end of play on 21 August. During those four days I completed 100 QSOs into 25 DXCC and 72 squares, compared to the previous four days when the total was zero. That was just on 6m, I worked some on 4m too. Before that there was a week with no Es here. Once the event is over, be it today or another day, no doubt there will be a week with no Es, and geomagnetic activity will eventually subside. In my mind that means 6m Es is closely related to geomagnetic activity.

I have been posting about these openings being related to geomagnetic disturbances on this blog for years. It has stopped surprising me and now I use the signs as predictors. I do not use the other much touted "predictions" produced by the great and good of our hobby, largely because I find that they do not work.

I believe that Sporadic E is caused by a combination of many factors so a simple explanation may never be found. This mechanism seems to have some effect, but I am pretty sure that it is only part of the story. However, I cannot ignore the coincidence of these events and this result:-

50MHz contacts at GM4FVM 18 to 21 August 2022

It is not certain exactly how this works, so I just accept that it does. However, one thing I am pretty sure of. Earth wind systems such as the Jet Stream seem to have no relation to Es openings as seen from GM4FVM. I have looked into the Jet Stream theory for a long time and whilst there may be some connection it looks to me that Jet Streams have no "cause and effect" relationship with Es and have no part to play in their predictability. On the other hand, I got the first warning of these openings on 14 August. That satisfies me that, at least in Spring and Autumn, keeping a watch on disturbed solar conditions is a good guide to finding Sporadic E openings.

73

Jim

GM4FVM and Aurora

Now That's What I Call A Tropo Opening (Number 115)!!

Hot on the heels of the Es opening, along came a Tropo one.

With the UK experiencing a long hot dry spell, another high pressure system arrived from the Atlantic to cause more scorched grass at GM4FVM.

As predicted in the last posting, where I reported DX in the shape of hearing Belfast Coastguard again, even more DX came along with the first reporting here of Holyhead Coastguard in Wales. Ah, a new ... well ... whatever you call VHF marine band DX. And for a time the entire VHF marine band was filled with Danish and Norwegian coast stations which are a bit harder for me to identify.

Amateur radio was also the beneficiary of all this enhanced propagation. Things had hardly begun when the RSGB UKAC 432MHz contest took place on 9 August. Conditions were a bit better than normal but my time at the microphone was limited and I worked only six stations. Maybe only six, but they were stronger than usual.

Dick, GM4PPT in IO75 asked "where have you been?", the answer to which should have been "hiding behind the Southern Uplands range of hills". The path between here and PPT is very tricky even though it is only 153km. My log, which is not very accurate when it comes to contests, suggests that it is eight years since I worked Dick, and it takes a lift to make it possible on 70cms. 

Contest ODX was as GI6ATZ in IO74 at 296km. Notable was a strong signal from GM4TOE in IO87 at 200km. Although I regularly work Barry on 1296MHz, this appears to be the first time I have ever worked him on 70cm. So things were a bit better on the evening of 9 August and everything in the pressure charts pointed to the next few days being open to possibilities.

By 10 August the 144MHz band as seen on PSK Reporter was beginning to look more like 80m:-

144MHz as seen on PSK Reporter at 20:38 on 10 August 2022

Over the four day period of the lift the bands opened in different directions on each day. For this purpose though I am looking at the whole period as one opening.

144MHz contacts at GM4FVM 10 to 14 August 2022

This is a pretty presentable set of results - 28 QSOs in 18 squares. 8 DXCC on 2m in four days is not shabby. The ODX of SM6BUN at 1028km in JO78 is good. Perhaps because I am getting used to fantastic results then just very good ones do not excite me as much. Let me just say that these days if I do not work SP or OM in an opening like this I feel a bit let down. That is crazy of course. This opening was characterised by lots of contacts over four days, other ones have fewer contacts and shorter durations, but they have better ODX. You cannot win them all, though I would like to.

Perhaps the results on 2m were influenced by the fact that I was concentrating on 70cms.

432MHz contacts at GM4FVM 10 to 14 August 2022

I spent more time on the 70cm band, and the result is that the map looks very like the 2m one. The openings covered the period of the "Euro FT8 contest" on 70cm as well as the RSGB UKAC 70cm FT8 contest too. That helped, but most QSOs were outside the contest. The contest certainly increased the QSO numbers to 59, as several stations worked me a second time during the Euro contest (and one three times to include the RSGB Contest too). Then there were several QSOs with G0BIX testing various things which brought up the totals again.

As is often the case during a tropo opening, ducts formed. Sometimes these can be long lasting, and sometimes very short lived indeed. The ducts create very strong signals in both directions but they are usually limited to small areas at each end of the path.

As an example of a powerful short lived duct here is a screenshot of my contact with PA3FWV on 11 August. I called CQ, and after the first call PA3FWV came back to me. We exchanged reports at +19 and +23dB.

 

 

Contact between GM4FVM and PA3FWV on 11 August 2022

I had heard nothing from PA3FWV before calling CQ. I have heard nothing from him since. I only heard him during three 15 second transmissions which were all during that one QSO at +19, +20 and +20. I have never heard him during any other lift. He had never heard me before. This was his first GM contact on 70cms. So this duct made possible a contact at very considerable strength between two stations who have no history of being able to work on 70cms, even during previous routine tropo lifts. 

I had not worked a station for 15 minutes before the contact with PA3FWV - that was SM6VTZ - and I did not work another one for 15 minutes afterwards - that was PA9R which gave me a -19dB report. The contact with PA3FWV stood out as a real indicator of the power of a tropo duct. It was completely out of character with the rest of the opening, as ducts so often are.

It would not be a tropo lift for me these days if it did not involve 23cm.

1296MHz contacts at GM4FVM 10 to 14 August 2022

Six QSOs, five squares, three DXCC, and an ODX to OZ2ND in JO46 or 690km. OZ1FF chipped in with a not inconsiderable 612km. You might think that is pedestrian but I loved it. I always say that raising operations to a higher band doubles the points for each QSO. And "points mean PRIZES" (whatever that means).

As so often on 23cm, OZ2ND and F5APQ are my targets. 690 and 605km on 23cm are quite respectable distances. Of course, when I started on 1296MHz I never expected to get anywhere near that far.

The path to Niels Erik is pretty straight forward - across the North Sea.

Path to OZ2ND from GM4FVM

On the other hand, reaching Jacques, F5APQ, is a lot more difficult

Path to F5APQ from GM4FVM

As usual you can click on any of the images to enlarge if you need to.

To get to F5APQ my signal has to pass over the headland near me, over the Northumberland Hills, across a stretch of sea past Sunderland, then over high peaks via the North York Moors, over the Humber Estuary, then over hills separated by The Wash, finally crossing the English Channel to France. This is a far more complex route than crossing the North Sea but not so far either. Or maybe the path to Jacques is just as long because it is indirect (see paragraphs below)

So working these two station make up two different challenges. The longer distance to Niels Erik is the easier to do, and I work him more often. Working Jacques is quite a task and although it happens less often it is just as pleasing when I can do it. While the hills to F5APQ are all under 400m, the route is bumpy and more obstructed than the flatness of the North Sea. Both tasks have their own issues and I enjoy hearing either station. To work both is a real pleasure.

Another anomaly which affected both 70cm and 23cm is that several station reported was that beam headings were not what we would usually expect. This may explain how it is possible for me to work F5APQ despite the difficult terrain. G0BIX on 70cm, G4ODA on 23cm and F5APQ (both bands) reported getting the strongest signals when beaming further East than expected i.e. towards the North Sea. This was at times when fog and Haar were being seen over the North Sea at GM4FVM, and strong Continental marine stations being received on VHF. 

Clearly it is possible at times to avoid the hilly overland paths (such as the one to F5APQ?) and find a longer but stronger path (reflection or duct or some other scatter mechanism?) by beaming towards a high pressure system off the main path. I knew this might be a factor on 23cm but I never expected it to work on 70cm. I need to learn more about this and try it more often.

The trick, it seems, may be not to beam towards a station when I hear it. My natural tendency is to assume that the direct path will be the strongest. I have had to learn that this is not necessarily the case with meteor scatter, and maybe not during tropo lifts either. 

And then it was over. Atmospheric pressure at GM4FVM started to fall. Rain fell to the benefit of the fruit and vegetables in the garden and to the detriment of radio conditions. Everything returned to normal. If it was not for normal I would never appreciate a lift.

The balance of activity I get by running both low VHF (50 and 70MHz) for Sporadic E etc. and high VHF, UHF and low SHF (2m, 70cm and 23cm) for tropo etc., means that there is often something happening. If you throw in my occasional EME activity then I usually have something to do, or something is about to happen.

This year I have hardly been present during the Perseids meteor shower. I have had a few contacts on 70MHz, particularly to Mek LA/SP7VC, but more on Mek in a later post. I even briefly ventured onto 2m meteor scatter when I heard DH8BQA. In general though I have been busy elsewhere.

That is it for now. Tropo followed Es. Time for aurora to follow Tropo? Or maybe an F layer opening to Australia on 6m?

73 Jim GM4FVM

When is a 50MHz opening really a 50MHz non-opening?

I am a great one for watching the Internet for opportunities to work DX.

Many sources of intelligence are used at GM4FVM, Solarham, PSK Reporter and often also the excellent DX Maps.

DX Maps is very useful on three counts. It has contact maps so that I know where to point my antennas. Then secondly the MUF Sp-E map is derived from that information and it shows the predicted maximum usable frequency for locator squares over Europe. This means that I can see Es developing and, perhaps more importantly, fading. And finally it shows lists of QSOs reported and also allows me to post formatted reports myself.

Here is a map showing all the activity as reported to DX Maps

DX Maps showing all reported 50MHz activity on 2 May 2022

Despite this there was no sign at GM4FVM that the 50MHz band was open.

When I went into the "Select Options" tab on DX Maps and chose "Only DX-Cluster" this was the map which resulted, which was much closer to what I was observing from here.

DX Maps showing "Only DX Cluster" on 2 May 2022

The difference between the two maps is, broadly, that the standard map shows anything reported (which includes automatic uploads), whereas the second one shows entries made by amateurs manually posting things to the Cluster. Not all of the manual postings to the cluster are for actual QSOs, some report simply stations heard, usually unusual ones. However, most of them are QSOs. On the other hand, the upper graph contains dozens and dozens of automatically generated reports many of which are simply single decodes.

The thing about this time of year on 50MHz is that there are a lot of stations calling CQ but not many having contacts. So these CQs get picked up and reported automatically by stations normally on receive. There is nothing wrong with this, but it tends to clog up the reporting system. Just decoding a single FT8 message (most are FT8, but not all) does not make a QSO. Not only is the E layer very unstable at this time of year, there is also the Eta Aquariids meteor shower which often generates these single decodes, plus of course random meteor pings.

Just selecting "Only DX-Cluster" often makes a dramatic difference. The effect can be seen on the "List" section of DX Maps which shows the postings in tabular form. Here is the latest one and as usual with images here you can click on it to enlarge the text.

DX Maps List on 4 May 2022.

When I clicked "Only DX-Cluster" every one of these red automatic entries disappeared to be replaced by a list of manual postings in black type. Basically, everything recorded had been a single decode and in one case the same signal decoded on two frequencies at the same time. As far as I could see nobody  was actually having a two way contact. Changing to manual postings suggested that, rather than several contacts every minute all over the Continent, there had not been a QSQ recorded for more than twenty minutes and the ones that were had been largely concentrated in a single area in Germany.

DX Maps is not the only site affected by this effect - PSK Reporter is too. In fact PSK Reporter is affected even more because you cannot switch it to "Only DX-Cluster". In that sense DX Maps adds a very useful ability to screen out almost all these one-off reports. Of course there will always be the odd one-off report, often due to random propagation enhancements, possibly caused by cosmic ray ionisation, orbiting objects, meteors, aircraft scatter etc. They can be quite fun to see on the higher VHF bands, but they never seem to last long enough to work someone. If only. I still reply to a few just "to be sure".

The very useful MUF Sp-E chart on DX-Maps seems to always include all the reports and you cannot screen out the "red" ones. It works very well when there is only really Sporadic E and not the random meteor scatter pings we are getting at the moment.

It is very handy to see the one off ones too, but it is easy to get carried away and think that there is an opening when there isn't.

For the record there have been a few short Es openings on 50MHz at GM4FVM but nothing on 70MHz yet. 

As for 144MHz Sporadic E, well that will have to wait until ... (who knows?).

73

Jim

GM4FVM

The drama of 144MHz Sporadic E, and how I nearly gave it all up.

Here's the thing about 2m Sporadic E ("Es"), it is very dramatic.

I was sitting here on Sunday 11 July 2021 at 15:59, musing over my previous successes and failures during previous attempts to work 2m Es. I was ready for an opening, but so far it had not happened.

For some time I have been learning how to apply my hardware set-up to try to be prepared for 2m Es openings. For instance, on 8 July I had been ready and I worked  IK8BIZ, IK6DTB, EA2Z, EA5TT, IU4CHE, IZ7UMS, IZ7UMS, IZ8OFO and IK0IXO in an hour long whirlwind of 144MHz Es. Key to this was that I was forewarned by activity on 70MHz.

That was common enough for me not to mention it on this blog at the time.

Just to put some context round this, my time trying for 2m Es from here had a very poor start. On 10 June 2011 I worked EU7AA on 2m, a distance of 2070km, and my only 2m contact of the day. It came as a complete surprise at the time. Of course I knew it was 2m Es because I had knowledge of 2m Es from before we moved here, but I was still in the dark about how to manage that aspect of VHF propagation. Looking back at the log, I had worked two stations in Estonia minutes before on 70MHz. If that was today I would have been watching 2m and be ready to pounce.

At the time I looked at "Make More Miles on VHF" and that site, which was focused on 2m Es, suggested that I might find three or four 2m events in a year, and those were almost entirely located in the Mediterranean or over the Alps. None of them came anywhere near Scotland. This seemed to me like an unpredictable means of propagation now that I had relocated north to GM-land. I decided not to go looking for 2m Es, and indeed I thought very hard about giving up on 144MHz entirely.

After that I did not work any 2m Es for four years, until three Italian stations popped up in June 2015. Those were the only Es contacts that year too. Make More Miles appeared to be correct - 2m Es was something that was welcome but not predictable enough to spend time looking for.

So what I was sitting here mulling over was - what has changed now that I think I can rely on finding multiple openings each year? I pulled out some facts. Up to that point in July 2021, the years so far has produced 55 2m Es contacts into 11 countries and 35 squares, with a best DX being IT9GSF at 2333km. 

2011, one QSO, 

2012 zero, 

2013, zero, 

2014 zero, 

2015 three, 

.... (must work these ones out)

2020 22, 

2021 so far, 55 (make that 77 by the end of the day, see later)

Then, to interrupt my pondering, up popped S58P to start a 90 minute 2m QSO-fest.

144MHz contacts (all over 1050km) at GM4FVM on 11 July 2021

22 QSOs in 8 countries. Dramatic or what?

If I include two tropo QSOs with GM and G, that brings me to 10 countries worked in just over an hour. Unlike 2011 I was prepared for this to happen and I reacted quickly.

DX Maps looked like a bad nosebleed (I have been having a few of those lately), so many stations were in the mix ...

144MHz on a 15 minute slice on DX Maps on 11 July 2021

And just to backtrack, I was interrupted by this opening. I had been musing on how much more common this has become. Basically I was analysing while I was waiting for it to open, when it opened.

Returning to my earlier thinking that day, I had done this map before the opening started.

144MHz Es contacts at GM4FVM 1 January to 10 July 2021

Not a bad map and it excludes the contacts in the first map above.

So has 2m Es got easier since 2011?

I know that I have mused about this before.

The subject came up in an email conversation with Andrew, G0JCC, and I suggested that FT8 is a big factor. He raised several things which affect 2m performance as well. These included better radios and better antennas. Also more information like DXMaps and alert emails. Certainly we did not have those before. He is correct.

Another key factor Andrew reckons are better receivers. He and I both have mast head preamps. Although their influence may be smaller on 2m than on 70cms or 23cms, they still help a lot. Correct again.

Everybody's setup will be different and will be affected by these many of these factors to a greater or lesser degree. In my case things that go with the grain here are using FT8 and more use of the lower VHF bands.

I doubt if FT8 really makes much difference in terms of distance reached, but getting us all listening on and calling on the same frequency has made a huge difference for me. And so has much more activity on 6m and 4m which makes predicting 2m Es so much simpler.

Since speaking to Andrew I have signed up for a 2m Es alert. I did it at www.gooddx.net who also do my 4m alerts. I was stuck in the past thinking that 2m Es was not for me.

Back in 2014, with no 2m Es worked since 2011, I almost gave up on 2m entirely.

Now in 2021, my analysis of previous successes on 2m Es this year was interrupted by another big 2m Es opening.

And during the opening on 11 July, I was called by Thomas SV8PEX. That would be a new country, and Thomas is 2406km from me, so a contact would also be a personal best on 2m Es. Of course I called him many times. We did not complete a QSO.

210711_161600   144.174 Rx FT8    -20  0.8 1752 GM4FVM SV8PEX JM99
210711_161618   144.174 Tx FT8      0  0.0 1750 SV8PEX GM4FVM -20

Later Thomas emailed me. He is as keen to work me as I am to work him. He confirmed what I had thought, that there was a large tropo duct in the Adriatic Sea, and that must have connected to the Es event. He said that he was hearing me for a long time, but he could not get through the pileup (!!!).

Maybe another duct, at either end, may make this possible eventually. My best 2m Es DX is still 2333km so it is not totally inconceivable. However, earlier in July I had emailed G0JCC with my view that working SV from here was "not practical". Clearly, once again, I don't know what I am talking about. Or maybe all those factors have changed my mind.

Still, SV8PEX heard me, and I heard him. That is good, but not a QSO. Next time, maybe.

I think that 2m Es is easier than it was, thanks to all these factors. However, it is still the ionosphere which calls the shots. However good your equipment, you still need nature to co-operate.

And, of course, I have my superior intellect to help me outwit the Laws of Physics.

Plus my often mentioned modesty and humility.

73

Jim

GM4FVM